The problems associated with time travel cited in the video are as follows — Luke

Great summary, thanks. All packed into less than a minute to boot.

1. Time is not a physical object that can be moved or manipulated. It's simply a measurement of the progression of events.

The video author seems also to presume presentism, implying that time itself would have to be re-wound (and the entire universe with it) in order to 'go back', rather than time being left alone and just the traveler going somewhere.
In non-presentist terms, it would require a discontinuous, or non-timelike worldline. Well, the worldline is just an abstraction, so it being discontinuous is not in itself a problem Several people have proposed valid methods to do (forward) time travel utilizing discontinuous worldlines.
Anyway, I have a problem with number 1.

2. The laws of physics, including the laws of thermodynamics, make it impossible to go back in time.

Not at all. But it presumes a self-contradictory version of dual-presentism, that the universe causality is made to go backwards (less entropy) but real time continues to go forwards.
Fact is, my abrupt appearance in 1955 would not violate entropy laws at all, nor would it violate thermodynamic law. It makes a hash of causality, but that's not brought up in this point.

3. The idea of travelling back in time would violate the laws of causality, meaning that an effect cannot occur before its cause.

This one has teeth, but is worded wrong. Causality doesn't say an effect cannot occur before its cause, it says that the effect (information travel) cannot occur outside the future light cone of the cause. The future light cone is physical and objective (not frame dependent). The plane of simultaneity (referenced by the word 'before') is frame dependent and an abstraction, at least it is under Einstein's theory. It isn't under presentism of course, so that assumption yet again.
Anyway, yes, backwards (not forwards) time travel would violate causality laws, if they're valid laws.

4. Time travel raises numerous paradoxes, such as the grandfather paradox, in which travelling back in time and changing a past event would alter the present and create a contradiction.

Closed time loops are allowed under relativity, but like several other things, that doesn't mean there are any at a classical scale. Time travel isn't itself paradoxical.
Also, what did grandfather ever do to deserve this abuse? If you want to illustrate the paradox, go back 5 seconds and kill yourself, or otherwise disable the machine, which would probably happen anyway with a 2nd machine materializing right in the same place.

5. Even if time travel were possible, it would require immense energy and advanced technology beyond our current capabilities.[/quote]This is nonsense. 'If impossible thing, then [arbitrary unfalsifiable conclusion]'. The energy requirements are meaningless unless a method to do it is proposed.

Point 2 says that time travel is impossible due to the laws of physics

Mostly point 3 that actually says that, seemingly the only point that isn't straight up unbacked conjecture.

Late in 2024, Bob enters his time machine for the first time and sets course for the year 1990.

A nit: He has to set his course for an event, which has 4 coordinates, not just one. Pretty much all the fiction (except xkcd) seems to forget that. Everything moves, but it is always assumed that the machine will reappear at the same map-location as it left despite the motion of stars, planets, etc. OK, Dr Who doesn't work that way. It's a car, and it travels in space as much as time.

However, I will argue, there must be two (or more) parallel timelines in order for time travel to make sense. The timelines branch off into two or more timelines following the first time travel event. Let's call them timeline A and timeline B. Timeline B differs from timeline A only by the addition of the time traveller (and all that causally follows).

OK, the 'spawn a new timeline' explanation. Yes, that avoids the grandfather thing, but doesn't resolve the physics violation of the machine in the first place, in particular, what caused the 1990 state with two Bob's in it.

On the original timeline (A):
1980(A) - Bob(A) is born
1990(A) - Bob(A) has the inspirational idea for time travel technology
2024(A) - Bob(A) builds his time machine and travels to 1990
2025(A) onwards - the world continues on its course of the original timeline (A)

And apparently Bob fails in his effort to destroy the bad thing resulting from his technology.

On the second timeline (B):
1990(B) - Bob(B) arrives in his time machine.
...
However far-fetched this may seem, it does not violate causality and leads to no apparent contradictions.

Um, that's a blatant violation. 'Old Bob' in 1990 is not the result of an antecedent state. If 2024 is the antecedent state, then the rest of this new timeline is not the result of that other antecedent state.

They stay exactly 1 meter away from each other for eternity. Is there time? — Philosophim

Well, you said 'for eternity', which implies time. But I agree that there is no meaningful time without change of some sort. You speak of an observer, but observing at all cannot take place.

To further your example, the particles need not remain a fixed distance apart. In a 2-particle universe, the distance between them is meaningless, as is rotation, so there is no need to state that they remain a meter apart, or remain in a given orientation.

Lets say the particles are a little misshapen — Philosophim

Now you go too far. A misshapen particle is not just a particle, but a collection of them. A misshapen particle has extension, and if it has extension, the distance between the particles becomes a meaningful multiple of that extension.


As for the OP

It is still the case that, if the universe had a begining (Cosmic Inflation, the Big Bang) then there was a time T0 where things existed and did not exist in any prior state. — Count Timothy von Icarus

It is not necessarily the case since eternalism suggests no such thing, as your seem to realize:

As I understand it, this problem is one of the things that makes eternalism popular. It would seem to solve the problem by saying that only what exists, including all moments, exists without begining or end. I find eternalism as a whole problematic for reasons that would make this post too long, so this never appealed to me. — Count Timothy von Icarus

OK, so it's a problem for your chosen interpretation of time. Einstein's relativity theory assumes eternalism by assuming the existence of spacetime. There are alternative theories that are more along the lines you suggest, but those theories took almost another century to be fleshed out, being in denial of the big bang, black holes, and other things that fall out of relativity theory.

So yes, even the eternalists have a problem if they assert that the universe is real. How does one explain the reality of whatever one declares to be real? It is sort of the 'why is there something and not nothing?' question. You have to answer that as well, even given your chosen interpretation of time.

But the point where the moving wheel touches the road is not a fixed point on the rim — Agree-to-Disagree

Ah, gotcha, and that made me re-read the way the OP was worded, and I think your take is more correct than the way I saw the question being asked.

The answer varies with starting assumptions. — frank

Trying to figure out which starting assumption (unstated) would reach an one (but not all) the other answers. For instance, I could assume that circle B is rotating, or that circle A is slipping, but either assumption leads to any of the answers being possible.
I'm also from a physics background where rotation is absolute, not something that is frame dependent.

The video does explain that. — Wayfarer

I didn't watch the video, so I'm just commenting on what is shown in the still shot. Surely the makers of the test selected one of the five answers as being 'correct', and surely somebody must have guess that selection, either in ignorance or in realizing that the correct answer isn't an option. The title suggests that this answer is selected by nobody, which is implausible.

If you insist that you can travel into the past or future in your imagination — Corvus

I never said anything about imagining. The comment to which you are replying was a reference to your pressumption of presentism. LuckyR seems to presume it as well:

Time travel exists, but only to the future, never the past (since, as stated) there is no "past" to travel to. — LuckyR

I personally don't insist that there is no "past' to travel to. I give equal ontology to all of spacetime, not just one 3D slice of it. Reverse time travel (as typically envisioned) is not possible because it would constitute transfer of information outside of somebody's future light cone, something which relativity forbids, and something which has never been demonstrated .

Strictly speaking there is no tomorrow in reality.
...
There is only "Now" for the whole universe and its members.

Your opinion, not mine. "Tomorrow" is a relative reference, sort of like (one km to the east). There is no objective location that is 'one km to the east', but relative to any given reference location in a place where 'east' is meaningful, there is.

What you call tomorrow is in your imagination as a concept or idea.

I am not speaking as an idealist when I made the comment. To me, 'tomorrow' is just as real as 'one km east of here'. All of Einsteins theories presume the same, but it is admittedly a presumption. There are alternatives to his theories that don't make this presumption, but they came almost a century later.

It's fine to presume such things, but a topic about time travel seems to require that the 'destination' exists in order for you do deny your ability to get there. You can't argue that it can't be done because only the present exists, because there's no way to prove that opinion.

But the point where the moving wheel touches the road is not following the path of a cycloid. It is a point moving in a straight line at the same speed as the car is moving. — Agree-to-Disagree

All this is wrong. A point on the rim of a rigid not-slipping wheel IS folling the path of a cycloid (not well depicted in the drawing which shows the path coming in from an angle instead of vertically), and is very much is stationary relative to the road, not the car. The axle is moving at the speed of the car, and no point on the wheel is ever stationary relative to the axle while the car is moving.

Am I reading your comment wrong? It seems you're just asserting things that are obviously wrong.

A thought problem along similar lines (or curves): "The SAT Question that Everyone Got Wrong" — wonderer1

The reason everyone gets it wrong is because the correct answer (4) isn't one of the options. It isn't because nobody can figure it out correctly. I've had that problem on a different test (not multiple choice) and got it right, as did a fair percentage of others.

It would be recreating the past in the future. — LuckyR

Recreating a piece of some past state. Indeed, this isn't time travel being described.
I can build a new 1928 Studebaker, even giving it the same serial number as one made in that year. Has that car time traveled or is it just a new thing? I satisfied the conditions of the OP by doing so. Is it even a Studebaker if I built it instead of the defunct company?

There's several physics violations made by the OP, mostly that the state of some system can be fully measured (violating Heisenberg uncertainty), counterfactuals, and violations of entropy, the latter of which can be fixed by recreating a finite state, just a system in a box, not everything.

The question for the OP scenario then becomes, how is the thing created in the box you? Suppose you recreate a 'you' while you're still around, outside the box. Clearly the created thing in the box is not you. Nothing has 'traveled' into the future.

That said, yes it has. If you look at the state of Earth in 1990, you'll find me there. Have I time traveled to 1990? It seems I have. The statement presumes there is a 1990 in existence to examine, which pretty much means presentism is abandoned, which says only today exists.

You cannot travel into a place where the destination doesn't exist. We are all nailed into the present until deaths under the universal law. — Corvus

This is what I mean. Corvus seems to assume presentism with this statement. The whole notion of time travel seems to assume otherwise, that there are 'other times' available as valid destinations.

Impossibility of time travel seems to be one of the universally necessary truth. — Corvus

Funny that you will nevertheless travel to tomorrow. I plan to see you there.
People talk about time dilation being time travel. It isn't any different than doing the same thing sitting still. You get to 'the future' either way, assuming you live long enough to get to the target destination.

On a different note, closed time loops are valid solutions to Einstein's field equations. So are tachyons, and nobody has any reason to suspect either actually exists anywhere, but it isn't mathematically impossible. They don't for instance violate things like the grandfather paradox, and don't require branching of timelines.

No it doesn't. See my other argument in that post: — Michael

OK, we're at an impasse. I did see the argument, and it begs, and you don't see that. We can both just repeat our stances forever.

1. A foo is a four-sided triangle
2. Foos are a metaphysical impossibility
3. Therefore triangles, if they exist, do not have four sides — Michael

This is yet again a begging argument. The whole purpose of the argument is to somehow determine how many sides a triangle has, which means we need to start from an agnostic position of not knowing. You don't do that. Step 2 says that Foos are impossible, which you cannot demonstrate unless you beg that triangles have something other than 4 sides.

The analogy is also poor since the Foo and the not-4-sided triangle are not physically identical.

The other issue isn't a begging one, but seems to hinge on another sort of fallacy.

We can conceive of something that is physically identical to us not having consciousness, therefore it is metaphysically possible for something physically identical to us to not have consciousness, therefore consciousness isn't physical. — Michael

So I can conceive of a universe that is physically identical to ours, except momentum being conserved isn't the result of supernatural intervention. A rock, in the absence of an external force acting on it, could continue at its velocity indefinitely without help from the supernatural entity carrying it, or however that works. Therefore it is metaphysically possible for something physically identical to us to not require the magic, therefore momentum isn't physical.

That I do believe leverages the same logic, but I don't know the name of the fallacy. Never mind the fact that I also leveraged the begging of the magic. This example was meant to point out the fault in concluding that momentum (or anything of your choice like say mass or a clock running) isn't physical.

Step 1 doesn't define consciousness. — Michael

It doesn't define what it is, but it blatantly defines it to be something not physical. You've not refuted this in any way.

Here's a different argument:

1. A p-zombie is physically identical to us but has no consciousness

No different than before. This is the same statement, stating right up front that consciousness is non-physical.

2. P-zombies are a metaphysical impossibility
3. Therefore consciousness, if it exists, is physical

3 doesn't follow from the prior statement. 1 asserts that consciousness exists, so 3 cannot say 'if it exists'. 3 should read 'consciousness exists, and is not physical'. It follows directly from 1 and line 2 is superfluous.

The argument is valid.

It isn't. 3 directly contradicts 1, regardless of the actual nature of consciousness.

Line 1 is just a definition. — Michael

A begging definition then.
1. A p-zombie is physically identical to us but has no consciousness[/quote]

Physically identical implies that the difference is non-physical. 'We' have something non-physical that the physically identical zombie doesn't. That's very much begging the conclusion. I mean the conclusion is drawn by step 3 without any additional unreasonable premises.Step 1 defines consciousness to be supernatural, and step 5 asserts that we have it, per that definition. How is this possibly not begging?

So I attempted to interpret this in a non-begging way, allowing consciousness to be a physical process. In that case the p-zombie would not by physically identical, but rather some physical difference rendering him unconscious,and an unconscious person does not plausibly behave like a conscious one. It would be like asserting that you with all your senses cut off (not to mention voluntary motor control), would still be able to function without anybody noticing the difference.
Under physicalism, both the conscious and unconscious people would behaves as their physical circumstances dictate. Somebody behaving as his physical circumstances dictate does not imply that he is not conscious, at least not until the argument is accepted, but it is fallacious.

An unconscious being is not a metaphysical impossibility, but I do notice that nothing in the 6 points mentions the fact that the zombie behaves like the conscious one, with no way to detect the difference. It doesn't take a medical professional to detect the difference between a conscious and unconscious person. They're in different physical states, so they might be physically identical except for whatever states render him unconscious, such as say sleep or anesthesia.

My apologies for replying to days-old posts, but I've been otherwise occupied.

The argument is that:
1. A p-zombie is physically identical to us but has no consciousness
2. P-zombies are not a metaphysical impossibility
3. Therefore consciousness, if it exists, is non-physical
4. Therefore either physicalism is false or nothing is conscious
5. We are conscious
6. Therefore physicalism is false — Michael

This argument seems to depend on consciousness having zero benefit or purpose. It would never have been selected for since it brings zero benefit. The argument makes somewhat more sense if one is in denial of evolution of course.
The p-zombie can function identically without the consciousness (as I do). It reports the same experience (except I don't in this conversation because I've been stripped of the vocabulary necessary to do so). So line 3 should be "Therefore consciousness, if it exists, is undetectable". It seems to be more of an argument for epiphenomenalism.
Lines 1 and 5 beg the conclusion, making the argument fallacious. I claim I am not 'conscious'. I would be lying if I said I was.

If physicalism was true, the non-conscious being would make the exact same argument as above, per line 1, demonstrating that the argument carries no weight.

We can conceive of something that is physically identical to us not having consciousness — Michael

This also begs the conclusion.

External stimuli such as light and sound stimulate its sense receptors, these signals are sent to the brain which then responds by sending signals to the muscles causing it to move in the manner appropriate to navigate the stimulus. — Michael

How do you know that this isn't a description about how you work? I mean if it was, then by definition you would not know it, so I guess I am asking how you would report that you know that this isn't a description of how you work.

P-zombies have no free will. Everything they do is a physical effect of prior physical causes. — Michael

How do you know that you have this sort of free will? Given many definitions of free will (that your choices are not the result of physical causes), I agree with your argument above. But then this zombie has no idea why anyone would benefit from that sort of free will. It sounds like a curse.

I think they're impossible too. — flannel jesus
Impossible because conscious experience is physical ... — Michael

By your definition it cannot be. You've made that very clear.

I wouldn't say impossible, but it's ludicrous to think there would be a couple of p-zombies carrying on, what to us would appear to be a deeply personal heartfelt conversation, while in fact their conversation is simply meaningless noises they are making for no reason. — wonderer1

Only because the language forbids using half those words for what the zombie is doing. It very much claims 'heartfelt', 'meaningful', etc, but they're apparently all lies. The zombies doesn't know that they're lies.

I am simply explaining that “I believe that I am a p-zombie” is false if he is a p-zombie and irrational if he’s not. — Michael

On that note, I present this:


One of these is a duck. It swims, quacks, and avoids predators. The other is a p-zuck, which does none of that by definition. It simply behaves as its physical circumstances dictate. No more.

It is impossible by any test to tell which is which.
The duck quacks, and reacts to a quack noise by another. The physical circumstances of the p-zuck dictate that it produces a series of air vibrations that the duck interprets as a quack, but the 'quack' statement as understood by the duck is false because that which produced the vibrations does not quack.
The duck also is not sure if it is itself a p-zuck since it cannot tell the difference and as far as the duck can tell by any test imaginable, it also behaves as its physical circumstances dictate. So it's potential conclusion either way is not irrational. It truly doesn't know. Neither does the p-zuck, but what it is doing is not 'concluding' or 'believing' and it cannot communicate its conundrum because it has no available language by which it can express what its physical circumstances are dictating.

I would say, if your claim were true, it would be a revolutionary finding — hypericin

It wouldn't be a finding at all. If it was true, nobody (not even I) would know for sure. Of course, I'm sure that 'knowing' things (and being 'sure') are all forbidden. But I do have whatever it takes to pass an interview for a technical job, even if it isn't knowledge. I have claims of it on my resume, all false apparently.

Apologies to RogueAI for somewhat hijacking this topic. It's about p-zombies still, but not much about having children. I have no way of knowing if my kids are conscious or not. Not sure if a new topic would cover any ground not already covered.

You could just say “I am a p-zombie”. — Michael

Most of us don't know it. It isn't easy to tell until you get a glimpse of the bit being missed, sort of like having your vision restored after cataracts have reduced you to near grayscale levels.

You’ll need to explain it in these terms. — Michael

Hence my attempt with the car, which very much is aware of its surroundings, but 'aware' is perhaps one of those forbidden words. It all smacks of racism. They basically degraded black slaves by refusing to use human terms for anything related to them, using cattle terms instead,.It made it easy to justify how they were treated. "Cows don't feel pain. Neither do p-zombies. It's not immoral to set em on fire."
I'm sorry, just because we're not conscious in the Chalmer way doesn't mean we don't hold beliefs. I refuse to withhold perfectly understandable terms when no alternatives are offered.

I don't agree with this. "so he says he feels pain, not knowing that it isn't real pain". That's an epistemic issue, not a truth issue. For any x, if x is not feeling pain/hurting, and x says it is feeling pain/hurting, x is wrong. X is saying something false. — RogueAI

I didn't say the statement "so he says he feels pain, not knowing that it isn't real pain" was true.
I said the statement, "pain hurts" is true regardless of what utters it.

But this isn't true for you. — RogueAI

That's just using a language bias to attempt a demonstration of a difference where there isn't one. A Roomba cannot be conscious because you define 'conscious' to only apply to humans. That doesn't demonstrate that a pimped-out Roomba isn't doing the exact same thing, it only means that the Roomba needs to pick a different word for the exact same thing, and then tell the human that he isn't that sort of conscious because he's an inferior human.

That's the sort of argument I see coming from everybody. The word is not legally applied to you, therefore you you're not doing what the chosen race is doing.

But belief is a conscious mental activity. P-belief/p-consider is incoherent. It's missing a necessary condition for anything that remotely resembles believing and considering. — RogueAI

What is the computer doing then when it processes data from a camera pointed at a table. The computer 'concludes' (probably a forbidden word) that there is a table in front of the camera in question, and outputs a statement "there seems to be a table in front of the camera". You say it's not a mental activity. I agree with that. That usage of "mental activity" only applies to an immaterial mind such as Chalmers envisions. So OK, you can't express that the computer believes there's a table there, or that it concludes that. How do you phrase what the computer does when it does the exact same thing as the human, which is deduce (presumably another forbidden word) the nature of the object in the field of view.
If you can't provide acceptable alternative terms, then I'm sorry, the computer believes there's a table there. Deal with it.

The answer is that it would behave as its physical circumstances dictate. — Banno

So I claim I'm doing. But how would you express what the p-zombie does when it correctly identifies the table in front of it that it cannot 'see'?

We don't behave this way — RogueAI

I do, and you don't. So why are we indistinguishable (except for me deciding to stop imitating the language you use for that which I cannot ever know)?

I don't have a computer algorithm in my head. My head does not implement a Von-Neumann architecture, even though I'm capable of simulating one, and a Von-Neumann machine is capable of simulating me. None of that is true of you. The lights are out for me, but I don't know it since I've never experienced the light and had that 'ooooohh' moment.

By definition they behave as we do. This includes belief. — hypericin

Well, per Michael, this includes false claims of belief. I'm doing something that I think is belief, but Michael says it's by definition false.

When humans say "pain hurts" it's true. When a p-zombie says it, it's not. — RogueAI

No, it's true by definition, regardless of what says it. The p-zombie might not feel actual pain, but says he does anyway since he very much detects the undesirable sense of injury, and he has no actual reference to what true pain feels like, so he says he feels pain, not knowing that it isn't real pain, just an interpretation of sensory data.

And, I'm not so sure a p-zombie would say that. Why would they lie?[/quote]Lies are intentional. The p-zombies doesn't know. I only suspect because there's something missing, something many others find obvious, but not all.

Wouldn't they just be confused about what "hurting" is?

You're definitely confusing me when y'all say there's a whole vocabulary that I'm not allowed to use, and without giving me replacement words. So I use the words.

I assume you are telling the truth when you say "pain hurts"

It is truth, but 'hurts' to me is just detection of signals of injury. It's not like I lie and don't actually get this sensory input. But the extra bit, that which I would be totally unaware except for people talking about how obvious and inexplicable it is, only the talk of that makes me aware of something more that should be there.

Perhaps they have desires and urges we're not aware of. — RogueAI

I would hope so. They invented sex after all.

Does pain hurt? Does it feel bad? — RogueAI

Yes, but any p-zombie or human would say that. It's not a question that distinguishes the two cases. I've been taught that 'hurt' and 'feel bad' are appropriate ways to express the state of my information processor when it detects signals originating from nociceptors. Most self-driving cars don't have these, so in that sense, the car is a poor example.

Not sure what having children has to do with being conscious. Things have been having children since eukaryotes, which arguably are not particularly conscious.

1. “I consider myself to be a p-zombie” is false because you are a p-zombie and so don’t believe anything. — Michael

OK, 'belief' is one of those things reserved. It is not appropriate to say that a self-driving car believes that steering onto the soft shoulder at speed would be a poor choice. Different language must be used.
All that said, the statement "I consider myself to be..." does not use the word 'believe'. If you equate them, then you really need to pony up a generic word that applies to cars and such which consider some judgement to be 'true'.
But a p-zombie making the same statement would be one of truth, even if the phrasing is designated to not be allowed by you.

The statement “I consider myself to be a p-zombie” is only true if you are not a p-zombie and so no rational person can believe themselves to be a p-zombie.

OK, so it's false, only because the actual p-zombie is not allowed to use the phrasing. The p-zombie differs on that ruling.

It is a thought experiment, it is an open question whether it is believable or not. — hypericin

Belief in it is critical to the argument. The p-zombie apparently isn't allowed to 'believe', so there's seemingly no position from which an actual p-zombie can argue his case.

Chalmers is full of descriptions of all this miraculous stuff that isn't physically possible. It's so obvious to the people actually conscious (his definition), leaving people like me wondering what the miracle is. There's nothing inexplicable. No hard problem, so the conclusion is that Chalmers experiences something I don't, something that cannot be conveyed to me, which is sort of like trying to convey the experience of seeing red to Mary. I can pick red out of a box of crayons by sight, as can a robot. Mary was never given a chance to, so I'm not sure if the analogy is apt.

I cannot think of anything I can do that a machine cannot. Chalmers has access to something that obviously is out of reach of the machine. The conclusion is that I'm missing what he experiences.

Are you conscious?. — hypericin

I react to data from my senses. So yes, I am conscious in the same way that a self-driving car is conscious of the traffic around it.
No, not conscious in the Chalmers sense, something more, something that machines cannot have. I've looked for the 'more' part, the part that is inexplicable, and find only the automaton.

I find it very hard to believe. — hypericin

Then the P-zombie argument falls flat because it is unbelievable that something could behave identically externally without that extra thing on the inside. The argument hinges on not being able to tell. So you must believe.

Do p-zombies ever look like they're in pain, or sad, or happy? — RogueAI

They'd act very different if they didn't look like that. As said in terminator, I sense injuries. The data could be called "pain.". I react in a way that attempts to minimize that pain, sometimes quite irrationally. The face expressions? Those seem to come from subconscious places to which I have no direct access. A sleeping (unconscious) person will still wince in pain given certain stimuli.

P-zombies don't have urges or emotions, so why would they reproduce? — RogueAI

They're supposed to be indistinguishable, so yes, they would display urges, emotions, and children. I consider myself to be a p-zombie. OK, my kids are a bit off the curve, but I display emotions and talk about qualia, mostly because I learned the language from you non-zombies, not because there's that inexplicable extra bit that seemingly defies 'physical explanation'.

Parfit, Personal Identity wonderfully covers the topic from a metaphysical point of view, but it seems you're looking more for sources discussing the biological origins of one's sense of identity.

Please show how "all points on a two dimensional surface that are equidistant from the center"
and these exact same points form four straight sides of equal length in the same two dementional plane. — PL Olcott

First you've mentioned 'straight sides'. Also first you've mentioned a 2D plane. This comes back to my point, which you predictably have totally missed besides it being emphasized multiple times: State your premises, because the assessment of 'impossible' or not depends on them.

I can still do it despite these new definitions.

On the surface of the Earth, — magritte

Tip O' the hat to magritte, who actually paid attention to my point, and similarly did not see a restriction to Euclidean space, which is interesting because our universe is not Euclidean, so it's not an obvious assumption to make. One can draw a square circle on the 2D closed plane of the surface of (an idealized) Earth. It would have four equal length straight sides.

changing the subject to the not logically impossible — PL Olcott

I think only a mod can change the subject of a topic, so it is safe.
So yes, just be more careful when selecting your logically impossible thing, because so far none of them has qualified. Then, having found some suitable impossible requirement, in order to make your point in the subject line, you need to come up with a scenario that lists it as a requirement. That was also missing in the OP. So let's say for argument sake that a square circle (suitably defined) is impossible. What argument would plausibly list that as a requirement?

It is logically impossible to draw a square circle because it must be perfectly round AND not round at all with four equal length sides. — PL Olcott

Not logically impossible. I suppose it depends on your definitions, and 'is perfectly round' is a poor definition of a circle. More like 'all points on a two dimensional surface that are equidistant from the center. Given that and 'four equal sides' (and maybe four equal angles to eliminate a rhombus) as a square, it is not logically impossible.
Relativity theory ran into that. It proposed something logically impossible, except to somebody who is willing to drop some obvious but unstated premises.

It is clear that the impossibility of creating a CAD system that can correctly draw square circles places no limits on what computers can do.

The inability to do an impossible thing isn't a limit? What is 'impossible' if not a limit?

It is less clear that requiring a program H to report on the behavior of another program D that does the opposite of whatever H says is a logical impossibility when we see that program H1 can correctly say what D will do.

Godel showed that the program H cannot solve the task to which it is put. You seem to know this since you reference the halting problem. I was just discussing this very thing in another thread.

So the when the {halting problem} requires a program H to always say whatever program D will do includes programs that do the opposite of whatever H says this is requiring the logically impossible, thus the same as requiring a CAD system to correctly draw square circles.

Again, I don't find it logically impossible. All you need is to prevent access of H to the inputs of D. This again illustrates the fact that you've presuming conditions which have not explicitly been stated, same as the square circle.

I am talking about creating a perfectly round thing that
cannot be round because it has four equal length sides,
thus a logically impossible square circle. — PL Olcott

Agree, squaring the circle is an exercise in what can and cannot be constructed with a compass and straight edge. But the thing you list as impossible can be done, even without drawing a rhombus, which fits your definition of a square.

Just cut the circle (without moving anything) into four 90 degree arcs. Make them a different color if that helps to visualize it. There you go. Perfectly round figure that is also a figure consisting of four equal length sides. That was really trivial. Point is (the important part): Don't be so hasty to declare something impossible.

First, the robots that beat humans at rock, paper, scissors 100% of the time essentially cheat (that is they don't have any "thinking" algorithm) — LuckyR

I disagree about it not thinking, but yes, it leverages its far faster reaction time to see what the human hand is going for and bases its choice on that. For that to work, it must think, and very quickly. It would be instructive to put the robot in front of a mirror.
It takes far less thinking to just pick a seemingly random choice, and quite a bit more to learn its opponent's habits and begin to anticipate subsequent moves.

As to robot vs robot, since there is no "data" to enter into the algorithm to truly predict what the other robot will choose, the programmer has used some other way to come up with a choice.

Well, the data is that it knows exactly how the other robot is programmed, and thus it knows that its choice is determined. But the programmer knows the task to be mathematically impossible, leaving him with nothing to attempt the task.

If one knows what the algorithm is, one can reproduce it.

But the robot does know its opponent's algorithm, and is nevertheless incapable of predicting its outcome. That's the point I'm trying to make: illustration of the difference between determinism and predictability. You seem to see it.

As to pondering leading to different choices with the same input, I agree with you that humans commonly use the same analysis based on memories, emotions, objective variables such as price etc, however the priotization of the numerous variables leading to different choices in essentially identical situations is a common human experience.

That it is, but the antecedent states are never the same. Something critical is different when a different choice is made. Humans cannot be aware of that because they're never get to do anything twice. An antecedent state is never repeated. So the common human experience is of not always choosing the same thing, which, coupled with a naive assessment of identical antecedent state, results in what others have called 'the illusion of freedom'.in choice. Perhaps this is what you're getting at. The 'other factors' is simply antecedent states that are not identical. A huge factor is simply memory of the last time this choice came up, and wanting to not do the same thing all the time, hence picking a different ice cream today because you remember vanilla from last time.

If what you imagine is going on in the Black Box of human decision making was actually true, when faced with a decision between two choices of equal merit, humans would be unable to make a choice, yet we do every day.

Humans don't freeze in that scenario. It's called a metastable state, and we have a very fast mechanism to break such states, as is necessary for survival.
It comes up frequently in electronics, say a race between the Jeopardy buttons to indicate the one contenstant that pushed his button first. What if it's a tie? The circuit cannot freeze nor can it pick both. A metastability breaker is put in to resolve the condition. Mathematically, the task is impossible, but the resolution hammers the probability of continued metastability down to super low probabilities.

Maybe you can guess what sort of field I work in based on some of that.

Well the programmer of the robot can predict with 100% accuracy what his robot is going to choose. — LuckyR

Can he now? Maybe if the program is really trivial, making no attempt to work out what the other robot would do. Otherwise, you need to back that statement up.

He can of course just do a test run and see what it outputs. Given identical antecedent states and a deterministic algorithm (both were specified), then it has to do that each time. But that isn't the programmer 'predicting' anything. It's past tense at that point, not a prediction of the future, but it is a prediction in terms of future runs, that it must output the same thing as all prior runs.

The machine of course cannot win at rock paper scissors. It by definition has to fail despite the fact that we programmed it to work out what the other robot will pick (paper say) and choose a winning output (scissors) instead. Despite it knowing the antecedent state of its totally deterministic opponent, it is incapable of making that prediction. Hence the story illustrating the difference between determinism and predictability.


For the record, they have robots that they trot out on talk shows and such, that play rock paper scissors against humans. It has a hand as its output. Each iteration effectively starts at the same 'antecedent brain state' and are fully deterministic. They win every time, but they never pit one against a similar robot, at least not on camera. It is entertaining as a human to try to beat it. Are humans so lacking in free will that a simple robot can predict you every time? No, it doesn't work that way. It's more of a illustration as to why machines are better at some tasks than are humans.

Unless his program notes (accurately) that the three options are equally probable and therefore it chooses randomly.

These are deterministic algorithms. A computer has no instruction for randomness, so no, there is no equal probability. Neither do you have such a randomness amplifier, even though creatures would have evolved one had there been any survival benefit to it.

As to the factor, lay persons call it thinking" or "choosing". I'm not much into labels.

I think the word 'pondering' went by. Anything (human, machine, whatever) can do that much even under hard determinism, so thinking" or "choosing" only lets you make a better choice. It isn't what is going to make it possible for an antecedent state leading to many possible resultant states. You seem to conflate a good choice with a free one. Your choice is not free by the definition you give.

Again, there are very few options available. One is that multiple resultant states are chosen, and then a truly random selection is made between them. So held the feeble old lady across the street, or take advantage of the feebleness and snatch her purse. You, being a good person, want to help her, but you also want the choice to be free, so you 'roll the dice' instead, and it picks 'mug her' this time (but not every time). So glad you have that free will.

The other option is possession. Your body/brain wants to mug her, but a supernatural demon has possessed you and makes your body (in violation of natural law) help her across the street instead. The demon is now responsible for the actions of your body, and not your own criminal brain, which is safely shoved into some kind of epiphenomenal state, lacking the free will to act out its evil intent. For this to work, somewhere natural law has to be violated, severing the intent of the brain, and instead reacting to something with no natural cause. It should be pretty easy to spot such an organ.

I’d love to hear the details of this trivial experiment. — LuckyR

You have a machine that is entirely deterministic and classical: It executes instructions, and its purpose is to win rock-paper-scissors. Make it as simple or complex, slow or fast as you want. Its opponent is an identical robot, and both of them know that. The way the program works is to predict what the other robot will do (something that is completely determined ahead of time) and play the output that beats that.
That's a demonstration of deterministic vs predictable.

If a Determinist can’t use his Determinism to predict outcomes, what is the practical value of this Determinism?

Who ever claimed that the view had a practical value? I suppose its value lies in the fact that true randomness doesn't come into play, a priority that ranks high in some people's opinion, notably Einstein who was quite vocal about his distaste of randomness (and non-locality).

You are still evading my question, trying to steer things to another track.

How can you believe in free will when you cannot identify the 'other factors' that allow more than one potential outcome to a given antecedent state? Or is this one of those faith things where you believe in something that you think sounds desirable when in fact you have no evidence for it? (for both having it, and for it being a good thing to have)

One explanation of this is that initial conditions Determine decision making but we just don't currently know those conditions with enough detail. — LuckyR

Doesn't work, per Godel. One can know the initial conditions perfectly and still not be able to predict the outcome. Pretty trivial to set up an experiment that illustrates this. Determinism or not is an unknown. Predictability is not an unknown.

Yes, there are things we don't know, and that's where belief comes in. But many go way too far and claim to 'know' that their beliefs are true.

Your post seems to have been entered mid-sentence.

You may be unimpressed with those who I have conversed with before (which is entirely reasonable) yet at least when they state a contrary opinion or fact those represent their beliefs. — LuckyR

If they state a contrary opinion, sure, since opinions are often based on beliefs. I try not to let my beliefs clutter a topic that isn't mine. I've been known to attack posters expressing beliefs in line with mine if I think their reasoning doesn't hold up.
I cannot figure out your stance. I can suspect it, but as I said, you seem really reluctant to identify the other factors that make multiple outcomes a reasonable likelihood, or why that would be preferable to a method that chooses best each time. So not sure if you're really happy to reply to my queries, which is OK, since again, it ain't my thread.

could you please enlighten me with what you're referring to above. — LuckyR

What, the different definition? I've mentioned that a few times. My choices are free if I'm the one making them, and not something else making them for me. Rabies was one example. I consider myself free willed because I'm not rabid, with my will being bent to the purposes of the Rabies instead of to my own purposes.
This is a pretty thin definition of free will which has nothing to do with determinism but it has not just a little to do with being responsible for one's actions. If I'm rabid, am I to be held responsible for trying to bite somebody?

It is my opinion that the best choices are made with classical methods, that is, not involving true randomness, which cannot make any decision better. Randomness is not to be confused with unpredictability. The latter might be very advantageous certain situations.

Well, since in your view, Determinism can have antecedent state X leading to many possible resultant states — LuckyR

Well, under MWI it can, but I never said MWI was my view, so the above comment seems to be just something you made up. Bohmian mechanics is the only other prominent deterministic interpretation and state X cannot lead to different resultant states according to it.

I am somewhat amused that you're stumped as to what additional factors might be responsible for multiple resultant states that are not "randomness", yet you provided one yourself. Namely traffic patterns when deciding when to cross the street. — LuckyR

Ah, so your 'other factors' are simply antecedent states of something other than the brain. Yes, hopefully all decisions are based on such things, else sensory organs would be pointless. But if you include all antecedent states and not just the brain ones, then under determinism 'antecedent state X leads to' only one resultant state (not an actual choice by your assertions), and under non-determinism, it still leads to only one resultant state unless either randomness or some physics violation goes on, the only two choices I could think of.

The street crossing example was simply an illustration of how an antecedent brain state (your words) can easily result in different choices being made, even if the universe is utterly deterministic.

Bottom line, I have previously conversed with Determinists who do believe 1) it's all about the antecedent brain state, — LuckyR

OK, the street crossing example pretty much shoots that idea down, but I seriously doubt a determinist would make any such assertion unless they're incapable of logic, which I admit plenty are.

2) what we subjectively experience as pondering is an illusion

I think I know what they mean by that, but it makes it sound like we don't actually ponder at all. Why did humans evolve such an expensive brain (that has killed so many of us due to its cost) if it doesn't actually help make better decisions by 'pondering' better? Pondering is there since it is simply a deterministic mechanism doing what it's supposed to do. The illusion is that it is free, by the definition where multiple subsequent states can result from an antecedent state. But by those assertions, not sure why 'free' would be a good thing. I have a different definition of a free choice, one where it very much is a good thing.

3) there is only a single possible resultant state.

That sounds like Bohmian thinking. If so, they're right about that one. Still, I'm not impressed with the quality of the determinists with which you speak if they actually say especially the first thing, but I am also not impressed with your ability to actually convey somebody else's position, especially given the statement above headed by the words "in your view" and then stating something that isn't my view.

You've been clear, though that none of those 3 features of other's Determinism is part of your understanding of it.

The third one was, but again, it's not my view. Again, MWI is deterministic and it doesn't even assert the 3rd point. It says you choose both flavors, but not equally. The percentages of worlds with each choice getting less imbalanced the further back the antecedent state is. Far back enough and there are worlds where you don't even find yourself at the ice cream shop. Further back than that there's worlds without a you to make a decision.

I apologize for assuming your brand of Determinism was similar.

I never said I was a determinist. I'm just trying to figure you out, and I still don't know the factor that allows you to not choose the same flavor each time given multiple identical antecedent states. You seem to evade the question, like it's embarrassing. You say you believe in free choice, but you don't identify the mechanism via which the choice might be different given the same antecedent state. Is it something only humans can do? Can I build a device that leverages the same technique? If so, how? If not, why not?

As a Free Will believer, I completely support the concept of (true) choice. In other words I believe that the conversation we each have in our minds where we go over the pros and cons, possible and probable outcomes, memories of similar incidents in the past, what have you, is where the choice is made, ie exactly as we perceive it in real time. — LuckyR

All that would be the same even under hard determinism. Are you changing your definition here?
A chess computer does the deliberation. A thermostat doesn't particularly, so I can see the difference there. The chess computer is probably slightly more determined than the thermostat (less sensitive to small environmental fluctuations), but each is only truly deterministic if physics is.

You defined 'true choice' before in terms of determinism, not in terms of deliberation:

Just to be clear, the ANTECEDENT brain state is what I describe as the physical and electrical state of the brain.
...
Long story short, in Determinism antecedent state X always leads to resultant answer Y, never Z. In Free Will antecedent state X can lead to resultant answer Y or Z depending on the decision making process which occurred. — LuckyR

This is pretty funny since by this definition, we have free will even in a deterministic world because antecedent brain state X does not always lead to the same decision being made since decisions are not solely a function of the brain state. The decision of when to cross the street depends far more on the traffic than it does the antecedent brain state.
The deliberation clause seems to define a choice vs something else, such as what the thermostat does. You seem to only consider very formal pondering with a sort of verbal conversation going on, an internal discussion of pros and cons and such. Most choices take place far quicker than allowed by this slow formal method with might take days. The decision to swerve left or right (or not at all) for the deer crossing in front of you is very much a choice, and doesn't have any time to do all the steps you list above.
The formal decision making process is also very nice, but it's not where the decisions are made. Your conscious (rational) mind for instance knows that drinking is destroying your life and you've vowed never to touch a drink again, and yet you find yourself drinking at the next opportunity. The rational mind is not in charge. It is only in an advisory role, and the actual decisions often take its advice, but like with the deer, the rational mind is way too slow and the boss takes over for such situations, and the boss often has very different priorities than does the conscious part. This paragraph is pretty much opinion and the result of a lot of observation and experience. Most of it is irrelevant to the topic at hand, but I thought it fit in well here.


So here you have a different assertion:

I happen to believe that while brain states can and do INFLUENCE decision making, that there is another factor beyond brain states that participate in TRUE decision making — LuckyR

What is this other factor? Because there is only one in physics, which is randomness. There is no other information that can help. So if you go by that, the only way to make a true choice is to ponder up two or more viable options and then make a true random (not determined) choice between them, perhaps weighted. There are physical ways to do that in a non-deterministic interpretation of QM, but human physiology doesn't seem to have any mechanism to leverage it.

That said, I suspect that your 'other factor' is something other than randomness, which puts you in option 2 above: Humans and maybe nothing else can violate physics. Magic in other words. Your shots are being called by a external entity, which is possession by my definition ,a loss of free will, not the gaining of it. Simple to prove: Just show the circuitry that is sensitive to it somewhere in a human, something that does something that violates physical law, with the resulting signal being amplified to action rather than the action that the no-longer free brain might have chosen.

Did one of those two options (randomness, possession) describe your 'other factor', or do you care to fill me in on a 3rd option?

I think I agree with you that there isn't really a difference between "will" and "free will". — Jerry

I will agree that you don't use a definition that makes the two cases distinct. Others, especially proponents of free will, probably do. There is a difference using the definition I gave, but many people don't use my definition, or worse, they do, but word it like possession is a good thing.

So just understand that I'm really just using the term "free will" because it's what most people use to denote this idea of one making choices not determined by anything else

Again, I think you should ask said proponent, since providing your own definition smacks of a strawman fallacy. It's why I'm trying to get a clear reply from those that I think are proponents.

I cannot conceive of why anything would want to make a choice that is not a function of anything else. With my street crossing example, that would entail choosing a moment without in any way basing the decision on when there is a gap in the traffic.

There very much are examples of possession, of free will being destroyed. You have this parasite that infects a creature (slug I think), makes it climb to high exposed places and wiggle it's butt enticingly in an effort to get eaten, which is part of the life cycle of the parasite. For that matter, rabies disease is an excellent example of the free will of the infected creature being taken over by the virus, making it do things it would not normally choose to do. All very nice, but it only applies to the definition of FW that I provided.

I also tend to agree that an indeterministic selection of choice based on randomness wouldn't be desirable; it runs into the same problems as determinism, that being the choice isn't yours.

Disagree here. A choice based (partly or entirely) on randomness would still be your choice, but it wouldn't be a better one.

So to me, to salvage our idea of free will, it must be the case that either: 1) we are capable of making our own choices despite being determined by prior causes, or 2) our choices are indeterminant in the sense that they are not determined by prior causes, but the mechanism by which the choice is selected is not random chance.

Let me try to alter that to something closer to that which I might agree.
It must be the case that either:
1) 'Choices' are defined in such a way that they can be a product of causal physics. (notice that whether the laws of physics are deterministic or not is irrelevant here)
2) Our choices are are not a product of causal physics, in which case anything that has choice violates physical law.
3) 'Choice' is an illusion.

Notice that I never said 'free choice' anywhere, but I suppose you can put that in if you can come up with a distinction between the two.
I think LuckyR would deny the first two, so he says there is no choice, the 3rd option.
Given the list above, I would pick 1. I define choice (true, free, or otherwise) as a physical process.
The biggest proponents of free will tend to lean towards the second option, but are reluctant to come out and say it in the terms I used. They propose a supernatural entity (the 'mind') using the body as an avatar, which is possession in my book, something that cannot be done without violation of physical law.

For what it's worth, btw, I don't think there must be a hidden variable of sorts in quantum mechanics,

Well that eliminates a good deal of the deterministic options then.

For the record, as a relationalist, I think I qualify as a non-determinist since multiple different states can claim the same prior state.
— noAxioms

Isn't this what I asked when I talked about events with multiple outcomes?

Under my relational view, events don't have outcomes. Only measured things exist relative to a given event, and outcomes of an event cannot be measured by that event.

In other words, causes that have multiple potential effects?

MWI says that.
I carefully worded my statement, which says that multiple different states can claim the same prior state.
Since you used the word 'potential', I think I can agree to it. You have some unstable atom (the cause), and it might decay at any time in the next minute, or not in that time. That's a lot of different potential outcomes. All those resulting states can claim the same initial state (the atom at the beginning of the minute in question) as its prior state. In MWI, all of them happen. In Copenhagen, god rolls the dice (as you put it) and one of them happens. I'd have to look up some others to describe how they'd spin it.

No one has been able to predict human decision making, no matter how detailed their knowledge of the antecedent state might be. — LuckyR

A very weak statement since gathering even rudimentary knowledge of the antecedent state would kill a person. Over short periods and at the bio-chemistry level, human physiology is very classical and would be quite predictable if the state could be measured. That is also a weak statement, amounting to an unbacked assertion. Still, the negation of it is pretty simple: Somewhere inside a human, physics is either violated, or (for unexplained purposes) quantum randomness is amplified. It would be a simple matter to look for structures where either takes place. Nobody has found one. Descartes put it in the pinial gland, probably due to the fact that it was safely inaccessible to falsification at the time. Any study of it would kill the subject.

If such predictions could be made, it would be concrete proof of Determinism and a solid refutation of Free Will.

The are already far simpler systems that are nevertheless unpredictable, and that doesn't prove indeterminism. The ability to predict a classical system would similarly not constitute any kind of evidence of determinism.

You seem to completely deny the concept of choice at all. Why? Are you trying to argue that you should be held responsible for any actions? That would be like putting your hand in the fire and subsequently complaining that it's not your fault that you no longer have a hand.

BTW my last comment ... that I addressed to you was actually meant for ↪Jerry! — Alkis Piskas

I figured that out pretty quick when you quoted the OP and said 'your thesis'.

Free will comes in because even this sort of hypothetical world seems deterministic, because everything obeys the laws, and if things obey laws (like a cellular automata for example), there doesn't seem to be room for anything in the world to have a say in the matter. — Jerry

Disagree here. Yes, cellular automata is usually entirely deterministic, although one can design one that isn't. I can create something in a cellular automata, or say a Turning machine (also entirely deterministic), that makes choices, so I disagree that there's no room for anything that 'has a say', unless, like LuckyR, you deny the existence of choice just because they're the product of the laws chosen.

There are other choices available. — noAxioms

I am, in fact saying your use of the word "available" is nonstandard. If an "alternative" will never be selected, is it really available? — LuckyR

By what definition of 'available' is that not the case? I mean, given unitary time evolution, entirely free choice (however you choose to envision it), some outcome will be chosen and the alternatives not chosen. It will never be chosen. So how is your use of the word 'available' any different that you consider the unchosen alternatives available?

Alternative scenario: Consider MWI, a completely deterministic interpretation of QM. In MWI, all the viable alternatives are chosen from a given state sufficiently prior to the choice being made. So by that use, all the available choices are chosen, and only the unavailable ones are not. What would your "outside observer who has true insight" say about if there was choice going on.

I had asked you for an example illustrating the difference between will and free will, or choice and free choice, or now a decision vs. a true decision. You have not done that, nor has Jerry, leading me to conclude that there is no difference and the adjective 'free' (or 'true') is meaningless in this context.
I gave an example distinguishing the two cases for a definition of 'free will' that I find at least meaningful.

Why do you all like to speak theoretically and hypothetically without any examples? Not a single example here. How can one relate all this with reality, the world, life and so on? How can one understand what do you actually have in mind? What is your frame of reference, the context in which you are referring to free will? — Alkis Piskas

I seem to not be the only one noticing this lack of distinction that lends meaning to the word 'free'.

Determinists (that I commonly interact with) say that the brain state BEFORE Determines what happens DURING and therefore afterwards. — LuckyR

Do the non-determinists say otherwise?? I mean, the statement simply says that each state is a function of prior state. Determinism doesn't seem to come into play since that's true even with non-deterministic interpretations.

For the record, as a relationalist, I think I qualify as a non-determinist since multiple different states can claim the same prior state.

we both agree (I think) that we have the power to choose from alternate options, and so possess free will, — Jerry

Well, I was looking for you or LuckyR to come up with an example of something having choice, but not free choice, will, but not free will. What distinction does the word 'free' make in either case? Both of you seem to equate them rather than hold them distinct.

I said that us having free will is dependent on the definition of it used, and I didn't assert any particular definition. I suppose I would define it as making one's one choices and not having them made for me by something else, my example of un-free will being a cat possessed by a demon. The demon gains the ability to make choices, and the cat loses it.

Is it not possible for an event to have multiple possible outcomes, particularly in our reality? — Jerry

An event is just that, one thing, and it doesn't have outcomes.
I think you're asking if a closed system in a given state can evolve in more than one way, and the answer is dependent on one's interpretation of QM. So for instance, the decay of an atom appears to be totally random, uncaused, but with known probability. But maybe that's only an appearance, and the decay is actually determined by some internal variable to which we have no access.
Quantum theory is a probabilistic theory, not a deterministic one. Most of the classical rules and intuitions are invalid, such as the whole concept of 'a system in a given state', something meaningless in most interpretations. Hence the quip about the moon not being there when unobserved.

And if it is possible for an event to have multiple possible outcomes, must it necessarily be random? — Jerry

What alternative is there besides 'random'?

Why would I want a decision to be based on a non-deterministic method? What possible benefit would there be in doing so? Even rock-paper-scissors only requires you to be unpredictable, without a requirement for any actual randomness.

Firstly, if antecedent state X ALWAYS leads to resultant state Y, there can't be decision making going on since there are no other choices to choose between, it's always going to be Y — LuckyR

This is a non-sequitur. There are other choices available. There is still a choice being made, and it is Y. It being entirely deterministic or not seems to have nothing to do with the fact that a choice is being made, and by something capable of considering alternatives.

Your definition of 'choice' seems to be different than the usual one, which is a selection between multiple options. You apparently think the alternative options are not open to being chosen, rather than your processes having the option, but rejecting them.
Going to court and pleading 'not-guilty because physics made me do it' doesn't stand up. Your criteria for making the selection is what made you do it, and it is that criteria for which you are responsible.

An agent who doesn't know what the future holds can still undergo a process of "decision making" even if that agent is fully deterministic and it will always make the same decision given the same starting state. — flannel jesus

Agree, and furthermore, if said 'agent' actually knew said future, it wouldn't really be an agent any more than is a rock, which sort of brings up a contradiction of an omnipotent omniscient being powerful enough to alter what it knew was going to happen. Either way, the being could not be both omnipotent and omniscient.


Have we lost Jerry?

I am arguing that the free will I'm talking about—which is generally the ability to "do different", make choices that can alter your future—is dependent on prior physical state, as there has to be some input from the external world that may trigger an internal thought or decision. — Jerry

I'm trying to take this apart. To 'do different' seems to simply mean that a choice is present. My typical example is crossing the street. One can go now, or 'do different' and wait for a gap in the traffic. Watching the traffic is the significant portion of the external input of which you speak.
Now the bit about 'alter your future' needs clarification. The future of a given moment is very much a function of your choices today. Choose to cross now, and the future is you in hospital. Choose wait and the future is you on the other side of the road. That makes it a function of your choice, but it doesn't make it an alteration of anything since from the standpoint of where the choice is made, there is not yet a future state in need of alteration.

free will (the ability to choose a path from multiple outcomes) is possible despite the external macro world (i.e. not the quantum realm in which things seem indeterministic) being deterministic

I don't see where free will comes into play here, vs doing the exact same thing without it. That's the part I'm trying to nail down. Having choice and having free will are not the same thing, but you seem to define it as simply having choice. Of course we have choice, else we'd not have evolved better brains to make better choices.
I do agree that classical (non-quantum) physics is deterministic, and our decisions seem to be made via classical processes using deterministic mechanisms. I see for instance no devices in biology whose purpose seems to be to leverage non-deterministic processes, despite the ease of evolving such mechanisms were they to be beneficial to fitness.
Looking at QM is just an excuse to point out that 'the future' is not set. Single random uncaused quantum events can be (and are) responsible for hurricanes and such, as well as your very existence, but none of those things were chosen.

Let me ask you directly: given that the macro-scale universe is causally determined

Well, it would be if physics was classical, but it isn't, so I cannot agree with a statement that macro-scale things are determined. They're just not. The existence of our solar system is a chance occurrence and would very likely not happen from an identical state of the local universe 10 billion years ago.

But again, this is off topic. Such things have nothing to do with free will or the lack of it, at least by most definitions of free will.

do you think it's possible to still have the ability to choose different paths (free will)?

1) Yes, it is not only possible, but critical to be able to select from choices. As I said above, we'd not have evolved brains to make better choices if this were not so. If that is your definition of free will, then we have it, deterministic physics or not. It is kind of a Libertarian definition.

Is the quantum phenomena involved in your assessment?

Irrelevant, and thus no, at least given that definition.

Just to be clear, the ANTECEDENT brain state is what I describe as the physical and electrical state of the brain. While pondering occurs (obviously) DURING decision making (assuming there is, in fact decision making). Thus they are different entities, but are not mutually exclusive. — LuckyR

But the subsequent 'pondering' is also describable as physical and electrical state of the brain. They're just a little bit later. This is of course presuming that 'pondering' is a function of the brain, which plenty of people deny.

Long story shory, in Determinism antecedent state X always leads to resultant answer Y, never Z.

Given said determinism, agree. It doesn't mean that decision making is not going on, that choices are not being made. That would be fate, something different than determinism.

In Free Will antecedent state X can lead to resultant answer Y or Z depending on the decision making process which occurred.

There you go. That definition says that there can be no free will given deterministic physics, and it even goes so far as to imply that truly random acts are the only example of free will.

It seems to me that what we tend to mean by free will is not that our actions are not determined (random), but rather that, free from external determination to at least some degree, I determine my actions. — petrichor

This I guess depends heavily on how you define 'I'. If animals are self-contained and make their own choices, but humans are special and have a supernatural 'mind' or 'soul' or however you frame it, then the animal is free willed, but the human body is possessed by this supernatural entity. The body becomes an un-free avatar to the possessing entity, which refers to itself as 'I', and thus 'I' (the supernatural thing) is doing the choosing, and yes, it is free. The avatar on the other hand is not free since it is reduced to puppetry. I see no reason why a free creature would yield its fate to an external agent like that, or how the two would find each other.

That's my take on dualism anyway. Not sure if that's what you're talking about by 'external determination', but I see no other way to interpret that.

And importantly, this determination is made consciously.

As opposed to what, choices made in your sleep? In the end, almost all decisions are made subconsciously since that is the portion in charge of actually making any decision. The conscious part seems to be an advisory role, and is often the originator of the significant choice eventually made. I say 'significant' for choices like where to plant the tree, and not more common choices like which key to press next on the piano, which requires decisions far faster than the conscious portion of mental process can handle.
Crossing the busy street is probably a conscious decision, but not always.

This seems to require that antecedent physical causes (or perhaps any causes) do not fully determine which choices I will make.

What it seems to require is a mechanism that amplifies the external (non-physical) input into something that makes a measurable physical difference. Has any such mechanism been found? I did a whole topic once on where evolution would take you if such a mechanism were available, and there was also available the external entity from which the signals could be received.

Why do you want to introduce freedom in a system? — Angelo Cannata

:up:

What would a non-determinant world look like? — Jerry

It would look just like the one you see.
Pretty much any QM interpretation with wave function collapse is non-deterministic.
The only popular deterministic ones are Bohmian and MWI.

There are still very much rules and regulations and causality, but not 'always'. For instance, the decay of some radioactive isotope is not caused in a non-deterministic interpretation. It would be a true random event. That doesn't mean that causality is gone and it won't hurt if you drop a rock on your foot.

Free will seems to have little to do with this debate. Indeterminism opens the door to some definitions of free will, but it does not grant it. Randomness is not free will, it is chaos, which is why we're evolved to avoid it in making most decisions unless the point of the decision is to be unpredictable.

I listed at least 4 definitions of free will and you didn't really indicate which (if any) of those you are talking about. There are other definitions, but I've never found one that turns out to be something you'd probably want to have, except the ability to get out of that jail cell. That one (essentially someone with infinite wishes to be granted) would be useful, at least to a single individual, but not to everybody in a society.

If it's generally believed that free will can't exist in a deterministic world — Jerry

Some define free will that way, as simply a choice not being determined exactly by prior physical state. The alternative is randomness, producing non-deterministic outcomes.
Anything that makes decisions seems to have evolved methods for doing so that eliminate randomness from the process as much as possible, so determinism seems to be your friend here.

If you want that sort of free will, all you need to have free will is to choose a quantum interpretation that isn't deterministic (and also allows the concept of identity). Poof! You have a valid non-deterministic description of the world which cannot be falsified.

But more people define free will as making choices that are not a function of physical state at all, not even random outcomes. It is unclear why this would be a desirable thing. I can think of examples where this would result in horrible decisions and almost immediate elimination from the gene pool.

There are other definitions: To do what one wants: I want out of this jail cell, but can't do it. I lack the necessary free will.
The non-superdeterminism definition (this is the one physics talks about when performing quantum experiments), which says there are monsters all around you but your choices of where to look and what to measure always makes you look away from them. You are prevented from gleaning the true nature of reality by these continuous superdeterministic choices being made for you.

Well part of the problem is that Free Will is purported to explain animal decision making only (not simple physical systems), thus terms like "non-deterministic world" implies that somehow nothing causes anything. — LuckyR

Don't see how that follows, so perhaps not understanding. Wind causes a leaf to flutter. How does this broader anthropomorphism in any way imply otherwise?

Remember it is Determinism that tells us that what we perceive as decision making every single day is, in fact an illusion and that in reality "decisions" are not the product of pondering, rather are determined by the physical and electrical state of the brain before the supposed "decision" is made.

This makes it sound like 'pondering' and 'physical and electrical state of the brain' are necessarily mutually exclusive, sort of like 'computing' and 'transistor switching' are similarly exclusive, instead of one consisting of the other.

My concern would be whether we would have the technology accurate enough to be able to observe whether the two light beams would have the same speed or not. — Gampa Dee

I have no idea what actually has been done. Yes, the technology is there. What you describe doesn't even change the frequency of the light, so some kind of interferometer would easily measure a speed change involving half a wavelength.
M&M had that technology 140 years ago, measuring the speed difference over one path vs another, with paths of under 10 meters in length.

Could you show me the experiments which proves this (reflected light has a speed of c)? I'd be interested.. — Gampa Dee

Experiments rarely prove anything. We cannot, for instance, prove that light speed is c in all directions, independent of frame. Hence it needing to be a postulate instead of something measured.

Nevertheless, the mirror thing can be falsified. You just have two mirrors in a vacuum in the same place moving relative to each other. Shine a light pulse at it and detect the reflected light from each. If they arrive at the same time (but different wavelength/frequency), then light speed is not a function of the motion of the mirrors. If light from the approaching mirror gets there first, then we need to rewrite the last 130 years of physics.

and that the particle-pair comes from an original single particle with spin zero — tim wood

This part is incorrect. The original particle does not have a known spin, zero or otherwise. It is simply a thing not measured.

The sum of the angular momentum of the two must then always be zero. — tim wood

The particle does not have angular momentum. Spin in quantum theory is not a measurement of its rotation, a classical concept meaningful only to something with extension. It just means that they send the particle through a pair of charged plates and it is deflected one way or the other, never not at all, and always the same magnitude of deflection. This has been dubbed 'spin', but the word has nothing to do with the classical meaning of the word.

It is a simple step to assume that before the measurement, the particle really has a determinate spin value that the detector measures. — tim wood

That assumption should not be made. I'm pretty sure it can be falsified. It's a counterfactual assumption, and I'm not sure how counterfactual interpretations describe the state before measurement.

The rest of the post seems to run with this assumption, and thus diverges from what Bell shows. I'm no huge expert, and could not exactly explain what Bell shows other than the fact that it cannot be explained with any classic model. I mean, otherwise you can treat entangled pairs as a pair of coins facing in unknown but exactly opposite directions, and the 'spin measure' is just a camera oriented a certain direction relative to the coin which must, if the cameras are aligned the same way, read heads on one and tails on the other (and nothing else, not 'edge', not 'barely heads, damn it's almost edge and hard to read'). But that model fails with entangled particle behavior.

I sent a post concerning this in the “The Newtonian gravitational equation seems a bit odd to me" thread. — Gampa Dee

Which I did not immediately see because you didn't reference me (reply to something of mine say) anywhere in it.

Therefore, it would have predicted the nul result because of this....the light was going to be c relative to the whole experiment — Gampa Dee

OK, so the M&M setup isn't the optimal experiment to falsify this particle theory.

Throughout the whole debate, W. de Sitter and, to some extent, M. la Rosa as well, had taken it for granted that starlight retains, based upon the formal Ritz theory, its original velocity resultant for the entire duration of its journey from binary stars to distant observers. — Faraj

Given that relativity theory was in its infancy at this time, this is a bold assumption. It's reasonable for inertial frames, but no inertial frame describes the real spacetime between stars. In the accelerating expanding frame that describes the universe at large scales, light speed (the rate at which the proper distance from Earth to an incoming light pulse) is not fixed, is not c. For instance, the light from some of the furthest objects seen by the Webb telescope was emitted from only a bit more than a billion LY away (proper distance), which is a lot closer than the emission distance of the light we see from galaxies closer by. Point is, the assumption they're making up there is not to be made lightly (pun intended).

If the combined velocity of reflected light, in the reference frame of the laboratory, is (c + v), then the ballistic theory, in question, is a new-source theory, in which starlight loses its initial velocities. By contrast, if the combined velocity of reflected light, in the reference frame of the laboratory, is (c + 2v) instead, then the ballistic theory, in question, is an elastic-impact theory, in which starlight does not lose its initial velocities. — Foraj

OK, I got that. I know the difference between the two now. They're both wrong, but they didn't know it at the time. Not sure if the spectra of binaries can falsify both since apparently the new-source theory produces spectra very similar to relativity theory (reflected light speed is neither c+v nor c+2v, but just c.

I could either continue to give you bits and pieces until we can figure out how I can send the whole thing. — Gampa Dee

Check the copyright. Is it legal to paste the whole thing here? You already pasted an email address, which is against the rules for some forums.
What question do you need answered?

http://www.lon-capa.org/~mmp/kap6/cd149.htm

Adding the velocity vectors yields vt + v c = 0 mi/h. — Gampa Dee

Yea, but I find it very deceptive to add those two vectors since it doesn't produce a meaningful result. There's no such thing as 'the total velocity of a system'. If the car was inside the truck trailer and moving at vc relative to the truck, then adding vc to vt would yield the car velocity relative to the road. But that's not what's going on here.

The page never asks what the velocity difference is between the two, but the key word there is 'difference', in which case, to get the car velocity relative to the truck, one would subtract the vectors: vc - vt which would yield 130 mi/hr or about 58.1 m/sec

So,the addition of vectors in this case is 0...but relative to what?

As I said, it doesn't yield anything meaningful. I don't like the example text. It obfuscates more than it clarifies anything.
It also mixes metric (kg mass) with American units (mi/hr). That's unforgivable in a physics text.
Their momentum vectors seem to have a ratio of about 4, but the text says the ratio is closer to 7. That's poor graphics.

The total momentum is therefore = c + t = -111,000 kg m/s

Yes, there is such a thing as total momentum of the system. That addition is meaningful.
I also protest 111,000. I got a figure a bit lower than that, but they seem to lose accuracy when they don't use a consistent precision. The car momentum for instance is over 20300, but they round that to 20k.

Again,we have a momentum,of -111 kgm/s....what does that even mean?

Just what it says. For instance, if, in space (no friction with road), the car were to hit the truck and stick to it in a tangled wreck, the new 5200 kg mass would be moving left at about 21 m/sec to the left, the total momentum / total mass. Momentum is conserved in a closed system. I put them in space to keep it closed since the road would very much be exerting forces if it was there.

I’ve read some things concerning vector additions that I just don’t get, which maybe you could help me out with. — Gampa Dee

Maybe. Don't know the problem.
You mean the equation a = GM/r² ? I suppose that would need a unit vector to make it into a vector acceleration and not just a scalar. Nothing on the right side as I wrong it is a vector.

It seems that this would imply the light as having a speed of .5c relative to the mirror

Well, no. In the scenario I outlined, when moving up it has a speed of .134c relative to the mirror, and in the reverse direction the relative speed would be 1.866. That still presumes light is independent of emitter speed.
With emission theory, you'd have to specify the speed of emission, not obvious with a light clock which just reflects the pulse back and forth and has no obvious emission event. I am also unsure what emission theory says about how the speed gets altered when hitting a moving mirror.

If you’re speaking of an observer moving at .866c, relative to the frame of the clock

I wasn't. I was speaking of the clock moving at .866c relative to the ether. Neither the observer nor the frame plays any role in the predictions. That's the general model that the M&M experiment was trying to measure.

then, accordingly, the observer should measure the light as having a speed of 1.886c relative to himself and still c relative to the mirror. However, there might be indeed some “apparent” speeds due to the Doppler Effect, but those aren’t real.

I would be interested in learning more about the scientific jargon...I will try to read up on this more.

If you accelerate at 10 m/sec² for 100 million seconds, you achieve a rapidity (or proper velocity) of a billion m/sec. You just add 10 a hundred million times.
But to compute velocity relative to the frame in which you were initially stationary, you add 10 using relativistic addition, all those times. The former adds up to about 3.3c, meaning at that rapidity you move 3.3 light years for every year of your travel. But the velocity is .997c relative to Earth. That sort of illustrates the difference. So if your ship is fast enough, you can cross the 100,000 LY galaxy before you die because there's no upper limit to rapidity.

here's the link that I told you about concerning the "double star experiement"....I hope it works.

Doesn't work. It's just a pdf file name without a website in front of it. I tried searching the web for any site containing that file name and got nothing.
I am interested. Tried googling it, but the name is too generic to get to what you're talking about.
Sure, 2 orbiting stars will alternate approaching and receding, but that just results in redshift and blueshift. I don't know how they'd decide that the images being looked at departed at the same time, so to speak.