I had mentioned the rock above. Yes, it very much is a measurement. Thing X (source of photon) has now caused an effect on said rock, and X now exists to the rock. That's how QM measurements work. It causes the state of X and the state of the rock to become entangled. The special equipment in labs is only special because it records the measurement precisely for the purpose of the knowledge of the lab guys, but measurement itself is trivial. — noAxioms
You can assert otherwise, but then we're just talking about different things. You asked me what it means for an extended object (not all in one point in space) to not be in a defined state at the present, and this is what I mean by that. — noAxioms
Then choose another word to refer to what I'm describing, else we cannot communicate.It seems like you do not know what measurement is. — Metaphysician Undercover
So when I open the box to check if the cat is dead or alive, what carefully calibrated device to I need to do this? It can be done in the total darkness if that helps.Measurement, by definition requires a comparison. The measurement devices in QM are calibrated to perform comparisons.
Agree, but a hypersurface is 3D surface in a 4D space, and under presentism, there is no 4D space, only the 3D 'all of reality'. It isn't a hypersurface anymore if it is all of reality, no? That was my point, and perhaps it is just semantic.Under presentism, there has to be a present hypersurface, and there has to be only one of them. Unless you pull the trick of denying objective reality etc. — Inis
For the "eternalists" and "block universe" advocates on the thread.
I want to know the status of "dinosaurs"? Are they truly extinct and vanished from the universe (except for their bones and descendants)?
Or are they still moving and inhabiting the earth in their region of the 4D space time block and the only reason we can't get back there is because our timeline won't curve enough to take us back? — prothero
Dinosaur world-lines exist in the distant past. — Inis
And that just seems to be a deliberate dodge of the question. — prothero
The eternalist stance (as I understand it is the past, the present and the future all have equal ontologic status. They all exist and are real in the same manner. — prothero
The problem is virtually no one actually believes that. — prothero
One can not empirically directly demonstrate the continuing reality of the past — prothero
Then choose another word to refer to what I'm describing, else we cannot communicate. — noAxioms
The rock is doing a comparison of photon detected vs photon not detected. The state of the rock is different depending on this comparison. — noAxioms
You say that the concept of motion is available to eternalists, but it seems logically incoherent to me. You claim that motion or change can(?) happen in the past or in the future, but it fails to explain when anything actually happens in the block universe. — Luke
Future events already exist, so have they already happened? — Luke
Interaction implies two way relationship, so perhaps a 1-way interaction.How about we say that things interact with each other, but interacting things do not necessarily measure each other. — Metaphysician Undercover
You're describing a different dictionary definition of the word. A QM measurement is nothing of the sort, unless you ascribe to the Wigner interpretation I guess. I'd rather not limit myself to such a solipsistic interpretation of QM. Even Wigner himself bailed on support of his own interpretation for that reason.Measuring is a special activity of comparison which human beings with minds do.
I don't think I used the term 'gather information' so far.Things which interact with each other are not necessarily gather information into one point. Do you know what it means to gather information? Or are you just making up a nonsense definition of that, to go along with your nonsense definition of measurement?
You make comparison sound like a decision. I'm just saying that the rock is in a different state with the photon than it would be without (or with a different) photon. It doesn't make a comparison between those two states. Nothing can since any system has access to only one of the two states.So the rock compares it's own state prior to its interaction with the photon to its own state posterior to its interaction with the photon? That requires a memory. The day you find a rock capable of doing that comparison, let me know.
Interaction implies two way relationship, so perhaps a 1-way interaction. — noAxioms
You're describing a different dictionary definition of the word. A QM measurement is nothing of the sort, unless you ascribe to the Wigner interpretation I guess. I'd rather not limit myself to such a solipsistic interpretation of QM. Even Wigner himself bailed on support of his own interpretation for that reason. — noAxioms
You make comparison sound like a decision. — noAxioms
Rocks have great memory. Ask the geologists. But that is on a classic scale. From a QM standpoint, all matter has perfect memory, hence physics' conservation of information principle. There, now I've used the term 'information', but the physics definition, not the one you're using. — noAxioms
Anyway, I think we cannot communicate on this subject. You insist on the everyday language meaning of my words and not the physics ones. — noAxioms
I don't understand your question. — SophistiCat
Again, motion is change (specifically, of position, or more generally, of any property) over time. How is this a problem for eternalism? — SophistiCat
There are timelines, and there are properties that change along those timelines. What, specifically, is incoherent in this picture? — SophistiCat
You are just needlessly confusing yourself with this existence business. — SophistiCat
Like I said, I don't see much use for it, but if you insist on talking about it, just think logically. Every event in a block universe has a spacial and a temporal coordinate: (x, t). So if you ask when an event exists, the only sensible answer is the obvious one: it exists at t. Just as if you ask where it exists, the answer would be x. — SophistiCat
Motion is a problem for eternalism because temporal passage is an illusion — Luke
It seems odd to call it "change" when nothing actually changes. — Luke
The disagreement between us seems to be that you (and some others) are speaking from a physics point of view, whereas I am speaking from a philosophy of time point of view. In philosophy of time, eternalism is an ontological theory (about existence) which says that all times equally exist and objective temporal passage is an illusion. — Luke
Eternalists have clocks. — Inis
Eternalism doesn't claim that, though — Inis
Eternalism is a philosophical approach to the ontological nature of time, which takes the view that all existence in time is equally real, as opposed to presentism or the growing block universe theory of time, in which at least the future is not the same as any other time. Some forms of eternalism give time a similar ontology to that of space, as a dimension, with different times being as real as different places, and future events are "already there" in the same sense other places are already there, and that there is no objective flow of time. It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time. — Wikipedia
So what? Eternalists claim that temporal passage is an illusion. — Luke
Prove it. I'll go first: — Luke
What is this flow supposed to be relative to? — Inis
If someone were to claim that one of the spatial dimensions did not exist, that it was an illusion, you would think they were joking. — Inis
I don't buy your distinction. What is the passage of time supposed to be relative to? And where is your proof? — Luke
I never said there was no time, but eternalism says there is no passage. — Luke
Clocks measure the passage of time, in their reference frame. — Inis
You claimed that there is an objective flow of time. — Inis
We should begin at the beginning: what are the theories of time under dispute here?
In one corner we have the B-theory. The B-theory says: there are times; the
times are structured by the relation x is r seconds earlier than y; this relation gives
time the same order and metric structure as the real numbers. And that is all.
In the other corner we have the moving spotlight theory. The moving spotlight
theory says that the B-theory leaves something out. In addition to the characteristics
the B-theory says time has, there is also this: exactly one time has the intrinsic
property presentness. (Maybe things located at that time and events that occur at
that time also have presentness.) Presentness is the “spotlight” that shines on just
one time. Moreover, which time has presentness changes. Some time has it, but
later times will have it, and earlier times have had it. The spotlight moves along
the series of times at a steady pace. It is this continual change in which time has
presentness that in the moving spotlight theory constitutes the passage of time, or
“objective becoming.” When B-theorists deny that the passage of time is a real
phenomenon they mean to deny that anything like this goes on; there is no such
property as presentness that is instantiated first by earlier and then by later times. — Experience and the Passage of Time - Bradford Skow
Why couldn't the same be said about the flow of time? What makes that an "incoherent misconception"? — Luke
...there is no objective flow of time. It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time.
I have to agree with Luke on this one. 'Passage of time' implies flow to the average person, and I don't think the typical eternalist would ever use that term. I wouldn't. Clocks measure duration (length in the temporal dimension), and you seem to equate 'passage' with that, but I don't, and neither does most of the literature, as Luke has been pointing out.You are conflating "passage of time" (which is measured by clocks) with the wikipedia expression "objective flow of time" (which doesn't exist). — Inis
Time travel into the past is coherent, because the past is real. Having actually occurred, — Metaphysician Undercover
Past events occurred. They're no longer occurring. Time is simply change or motion. It's not something you can "travel in." It rather is the traveling so to speak. — Terrapin Station
You mean change something that changed so that it doesn't change that way? How would the idea of that even make sense? It would be an identity violation for one. Remember that time only is those changes. It's not something aside from them. — Terrapin Station
You can't "travel in change," the idea of that is just nonsensical . — Terrapin Station
That change is an identity violation is tautological. — Metaphysician Undercover
There must be something which changes or else there could be no change. — Metaphysician Undercover
How is the idea of traveling in change nonsensical? — Metaphysician Undercover
I didn't say that change is an identity violation. I said that the idea that we could "take back" something that changed is. — Terrapin Station
Look at what I wrote again: "You mean change something that changed so that it doesn't change that way?" That's what would be an identity violation. Change isn't. — Terrapin Station
By not making the slightest bit of sense. You'd have to explain what it would be to "travel in change." Changing isn't the same thing as "traveling in change." Change isn't a place that you can move around in. Change is a process. "Traveling in change" would mean that change is some sort of "thing" that we can move around in . . . which is a difficult idea to even clearly express in words, because it's just completely nonsensical. — Terrapin Station
You want to propose somehow "traveling back to that change," to experience it again, or to change it some other way, or whatever. — Terrapin Station
How exactly would it make sense to "travel back to that (particular) change"? — Terrapin Station
Let's say that all that you really mean is changing D, E, and F back to A, B and C, and then A, B and C change to G, H and I instead. Well, that's just two additional changes. It doesn't somehow erase the initial change. That's still there. We just had further changes.
So you'd have to explain how it would make sense to "travel back in change." — Terrapin Station
How is this different from any type of change? All change is a matter of taking back something that already is. that's just what change is, and it is by definition an identity violation. — Metaphysician Undercover
Now, no matter what we do, A was five feet to the right of B — Terrapin Station
Your premise is that time is change. So "was" in the sense of "past time" is meaningless by that premise. You have nothing to differentiate past change from future change. All we have is either A is five feet to the right of B, or A is not five feet to the right of B. And either of these can be changed through time, which is change.
If you want to introduce a premise which states that something which has occurred in the past cannot be changed, then you need to allow that time is more than just change. You need a premise which gives past changes special status over future changes, as being unchangeable. — Metaphysician Undercover
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