A (psycho-) ceramic rainbow.

You could as well have said "Hume says this, but clearly it is absurd, therefore he is wrong". — Echarmion

Not necessarily wrong. It just means he has the onus of proof. Absurd, common sense, reasonable, status quo, all these are terms which serve to establish who has the onus of proof. Once the onus of proof is fulfilled, then the claim stands, even if it is absurd.

Oh that's clever. So you get to set the status quo and then get to ask everyone for proof? — Echarmion

I don't set the status quo. I discover it by experience. If you want to be formal about it, you could survey what most people believe about hallucination and the normal. My money is that hallucinations are not seen as normal.

the teapot is too small to be revealed even by our most powerful telescopes. — Echarmion

Practical limitation does not entail that a thing is theoretically unobservable; unlike spirits for example.

Dictionary definitions are not arguments. That's how the term is generally used. Hume essentially questioned whether that use was actually correct. — Echarmion

My discussion, my rules. By objectivity, I mean "external reality" as per the dictionary, and that's how it will be used in this thread. :cool:

I don't think that those are the two only options. When discussing metaphysics a "true agnostic" position exists, i.e. there are simply things we can't make reasoned statements about one way or another. — Echarmion

Unfortunately, if you don't make metaphysical claims, then philosophy is impossible: Metaphysics is the science of what is real. If no knowledge of reality, then no truth (defined as conformance to reality), then no philosophy (defined as search for truth).

And actually... I just realized that the Principle of Parsimony is nothing but Abductive Reasoning, which is a fundamental law of thoughts.

So you claim that when we perceive an object, it is never the object in reality. And why would that be? If it looks, sounds, and feels like a duck, is it not reasonable to believe it is in fact a duck, until given a reason to believe otherwise? — Samuel Lacrampe

Strawman. Given the context of my last post, it should be pretty clear that I'm explicating Hume's views, not mine own. You should abide by the principle of charity instead of cherry picking and coming back with this kind of response. In any case, whether Hume's theory of perception is workable or not is besides the point. The point is that the principle you're forwarding doesn't address Hume's point at all. This is not surprising since you have thus far demonstrated an inability to understand what Hume's position even is.

It's like one person saying, "God doesn't exist because of reason X," and another person saying, "But I can show you evidence for his existence. Just the other day he made the sun rise." But if person #1 is denying God's existence in the first place, then person #2's evidence is misses the point. This is because it presupposes the very thing person #1 is arguing against (i.e. God).

That's what you're doing. Your principle doesn't circumvent Hume's criticism at all, because it presupposes or takes for granted the very thing that Hume is arguing against. Your "solution" doesn't work because it's one step removed from where it needs to take place.

YES. [...] — unenlightened

Well I am genuinely impressed. Nevertheless, this lack of trust, of assuming dishonesty until proven otherwise, is unreasonable. It fails the Presumption of Innocence. And I still maintain that most scientific demonstrations cannot be replicated by most people. If a cancer expert diagnosed you with cancer, would you spend the time to replicate the test yourself prior to going for treatment?

It comes to the same thing. Subjects can only know they perceive the same thing by communicating. — unenlightened

This also applies to some scientific tests such as testing new painkillers. Anyways, I'll do you a solid. Let's add the condition that the PUP is valid as long as the subjects are honest.

Here's one you can do yourself on your next holiday. [...] — unenlightened

This demonstration presupposes that the sun is far away from the earth. Flat Earthers would disagree. :razz:

I'm not sure I understand your point. Let me try to summarize where I think we are.

Problem 1: Either some perceptions are true, or else all could be an illusion.
Solution 1: Appealing to Principle of Parsimony, the former is more reasonable than the latter. It thus becomes the Prima Facie.

Problem 2: Some perceptions are true, but we know some are not (e.g sometimes my eyes fail me when I've been drinking). How to validate the perceptions?
Solution 2: Appeal to the Principle of Universal Perceptions. If the perceptions pass the PUP, then the belief that the perceived object is real becomes the Prima Facie.

Is there a problem still pending?

So if I understand correctly, "belief" in our common language is a catch-all term which could mean either "guess", "estimate", "supposition" or "opinion", and as it is less clear than the other terms, it should be avoided. I can accept that. Can't deny that clearer is better.

Hello.
Fortunately, we have principles of reasonableness like the Principle of Parsimony, to keep us grounded in common sense, and prevent us from getting lost into too many "What if" questions.

Given the context of my last post, it should be pretty clear that I'm explicating Hume's views, not mine own. You should abide by the principle of charity instead of cherry picking and coming back with this kind of response. — Wolfman

Well I thought that since you were defending Hume's position, you agreed with him. My bad for assuming. Bonus, I didn't know about this Principle of Charity. That's a good one.

As for Hume's claim: If he claims something drastically different than what I described in the OP, then we can discard it. It doesn't make the PUP any less valid on its own. Now for fun, we could try to examine Hume's true claim, or else leave it there. Up to you.

I'm not sure I understand your point. Let me try to summarize where I think we are.

Problem 1: Either some perceptions are true, or else all could be an illusion.
Solution 1: Appealing to Principle of Parsimony, the former is more reasonable than the latter. It thus becomes the Prima Facie.

Problem 2: Some perceptions are true, but we know some are not (e.g sometimes my eyes fail me when I've been drinking). How to validate the perceptions?
Solution 2: Appeal to the Principle of Universal Perceptions. If the perceptions pass the PUP, then the belief that the perceived object is real becomes the Prima Facie.

Is there a problem still pending? — Samuel Lacrampe

Having reread the OP it seems I got the wrong end of the stick. Sorry. I forgot to address the Principle of Parsimony adequately. My apologies. I really appreciate you invoking it to prove your point that some perceptions are true. Great! However, the Principle of Parsimony, as used by you, is a double-edged sword for just as you used it to show the likelihood that some perceptions are true, it can also be used to show that the odds are in favor of it all being an illusion.

Which would be easier or, if you prefer, more parsimonious: an illusion of a universe or an actual universe? The answer to that question is, according to none other than the Principle of Parsimony: an illusion of a universe is simpler than an actual universe. Hence, it must be that it's more probable that all is an illusion rather than there are true perceptions. It seems, to avoid a contradiction, we're forced to conclude that you've made an error in applying the Principle of Parsimony.

How and where does the Principle of Universal Perception fit into all this? Since it's more likely that all is an illusion (as proven above), the PUP is only there to bring some consistency into the illusion: the more people make the same observation, the more consistent it is. This is then taken as a surrogate for actual reality.

Why is consistency important? It seems consistency evidences a shared illusion, something we can make sense of.

Not necessarily wrong. It just means he has the onus of proof. Absurd, common sense, reasonable, status quo, all these are terms which serve to establish who has the onus of proof. Once the onus of proof is fulfilled, then the claim stands, even if it is absurd. — Samuel Lacrampe

I am not a fan of "burden of proof" type arguments outside of a legal context. While I think the general rule that the one who advances a claim is obligated to provide justification is a fine one, it's a rule of debate, not a law of (meta-)physics. I am repeating myself here, but there is no reason to suppose that the world cares about the burden of proof.

And I think it deserves repeating here that "it's a hallucinations" is merely a metaphor for what Hume means. A Hallucination is a specific way in which one persons perception differs from the perception in others in defined, pathologic ways. Hume's scepticism goes deeper than that. It's not about individual mistakes but about whether humans are at all equipped, sensory or otherwise, to gain knowledge about metaphysical reality (by which I mean whatever reality is like before or outside of human perception).

I don't set the status quo. I discover it by experience. If you want to be formal about it, you could survey what most people believe about hallucination and the normal. My money is that hallucinations are not seen as normal. — Samuel Lacrampe

But this just seems to bring us back to the starting point. Why is the majority opinion relevant for what is metaphysically real? Hume is not, after all, worried about individual failures of judgement but by a general inability to prove metaphysical propositions.

Practical limitation does not entail that a thing is theoretically unobservable; unlike spirits for example. — Samuel Lacrampe

While you are correct in general, for the purposes of the example given by Russel the distcinction doesn't matter. For any given ability to observe, one can make up teapots that fall just outside of it.

My discussion, my rules. By objectivity, I mean "external reality" as per the dictionary, and that's how it will be used in this thread. :cool: — Samuel Lacrampe

Sure, but then your statement "reality implies objectivity" reads "reality implies external reality", which is wrong, as there are obviously internal realities.

Unfortunately, if you don't make metaphysical claims, then philosophy is impossible: Metaphysics is the science of what is real. If no knowledge of reality, then no truth (defined as conformance to reality), then no philosophy (defined as search for truth). — Samuel Lacrampe

I think you misunderstand what metaphysics is about. Not all philosophy is metaphysics. Metaphysics is specifically about the "real-ness" of physics, not things like e.g. normative statements (morality). So even if metaphysics would be impossible, there'd still be truth. There just wouldn't be any truth about the connection between physical reality and metaphysical reality. And an agnostic position is still philosophy - the corrollary to finding truth is finding what we cannot know.

And actually... I just realized that the Principle of Parsimony is nothing but Abductive Reasoning, which is a fundamental law of thoughts. — Samuel Lacrampe

Which is good, if you think that thoughts construct reality. Do you?

This demonstration presupposes — Samuel Lacrampe

What a foolish demonstration, to presuppose something. It is however an example of the way science proceeds, not by asking if everyone agrees, but by inviting them to see for themselves. And your objection is one that might be better accommodated by another experiment, rather than by asking what a bunch of fuckwits think.

Which would be easier or, if you prefer, more parsimonious: an illusion of a universe or an actual universe? The answer to that question is, according to none other than the Principle of Parsimony: an illusion of a universe is simpler than an actual universe. — TheMadFool

Wait why is the illusion the simpler explanation? In both cases, true or false perception, some sort of universe must exist for us to have a perception of it. But in the illusion case, we must posit the state of having an illusion on top of having a universe. Then to be picky, we must also posit an explanation for why the illusion is so structured and consistent (as opposed to continuously changing). With that, I would say the actual universe is the simplest explanation.

I am not a fan of "burden of proof" type arguments outside of a legal context. While I think the general rule that the one who advances a claim is obligated to provide justification is a fine one, it's a rule of debate, not a law of (meta-)physics. I am repeating myself here, but there is no reason to suppose that the world cares about the burden of proof. — Echarmion

But the point of (sincere) debate is to find truth. Proper rules of reasoning and debate (which includes burden of proof) is part of epistemology. You might as well say that the objective world does not care about epistemology as such, which is true, but would miss the point that the function of epistemology is to know the objective world.

A Hallucination is a specific way in which one persons perception differs from the perception in others in defined, pathologic ways. Hume's scepticism goes deeper than that. It's not about individual mistakes but about whether humans are at all equipped, sensory or otherwise, to gain knowledge about metaphysical reality — Echarmion

That's fine. Instead of "hallucination" let's called it "false perception", for which "false" means "not in conformance with reality".

For any given ability to observe, one can make up teapots that fall just outside of it. — Echarmion

We (at least I) may have lost track of what the original point was here. If that's okay, we can leave this tangent as is.

Sure, but then your statement "reality implies objectivity" reads "reality implies external reality", which is wrong, as there are obviously internal realities. — Echarmion

I don't believe so. There are only 2 categories of being in that sense: real and imaginary. E.g. a horse is real, a unicorn is imaginary. By "internal reality", I am guessing you actually mean "imaginary" which is the alternative to being real.

[...] So even if metaphysics would be impossible, there'd still be truth. [...] — Echarmion

I still challenge this claim. Ethic is only properly speaking a science if it is objective; which means that goodness exists in reality. But if no goodness in reality, then no ethics. Similarly, there is no such thing as "physical reality" if we can know nothing about reality. Even if the physical is the result of a false but universal and consistent perception, we are then still claiming that this false perception exists in reality.

Which is good, if you think that thoughts construct reality. Do you? — Echarmion

Of course not. But true thoughts are thoughts which content conforms to reality. And true thoughts are possible only if they follow the laws of thoughts.

Haha! True that.

Wait why is the illusion the simpler explanation? In both cases, true or false perception, some sort of universe must exist for us to have a perception of it. But in the illusion case, we must posit the state of having an illusion on top of having a universe. Then to be picky, we must also posit an explanation for why the illusion is so structured and consistent (as opposed to continuously changing). With that, I would say the actual universe is the simplest explanation. — Samuel Lacrampe

To create an illusion is much much easier than creating the real. You seem to think that the illusion is an add-on feature to the real world, thus making it more complex than just having the real world. The illusion I'm referring to is, for sure, an added feature to the real world but one that needs only the very basic ingredients of perception (brains/minds + maybe a sensory system) and the rest of the universe is an illusion.

Which would be simpler?

1. A brain in an actual world

or

2. A brain in a vat?

Before you answer the question, I'd like to bring up the issue of simulated universes like the ones we see in the gaming world for its similarity to a world that is all illusion.

If you've played a sim universe game, you'll notice that only the parts of the sim universe the player is directly perceiving needs to be simulated; the parts of the sim universe the player isn't in, isn't and needn't be simulated at all.

Compare that to an actual universe in which the entire universe has to be even if we stop perceiving it completely e.g. when we're asleep or we die. Which universe, a simulated illusory one or an actual one, is more parsimonious now? In an actual universe, we need brains/minds + the entire universe but in a sim universe, all we need are brains/minds + only parts of the universe these brains/minds are actively perceiving.

You might ask about the "machine" (machine 1) creating the sim universe but it would, for certain, not be as complex as an actual universe. Here I ask you to compare the "machine" creating the sim universe to another "machine" creating an actual universe (machine 2). Machine 2, having to maintain the entire universe at every single moment in time, whether there's perception going on or not, would be far more complex, by many many orders of magnitude, than machine 1 which only needs to simulate the parts that are being perceived by brains/minds.

Well I thought that since you were defending Hume's position, you agreed with him. My bad for assuming. Bonus, I didn't know about this Principle of Charity. That's a good one. — Samuel Lacrampe

OK, let's take a look at the OP.

The Principle of Universal Perception (PUP) states that if a large majority of subjects perceives the same object, then it is reasonable to conclude that the object perceived is objectively real. It links the metaphysical with perceptions. [Note that even though I came up with the name, this principle has been used implicitly before by philosophers like by C.S. Lewis and Peter Kreeft. — Samuel Lacrampe

It seems to me this statement can be viewed in one of two ways. (1) You are either making a claim about how we already do things (i.e. using witness testimony to corroborate facts), or (2) or you are concluding from your argument that philosophical realism holds.

In the case of the former, this is a trivial claim with little philosophical import. In the case of the latter, the argument is fallacious because it is begging the question. Your premise already assumes that external objects exist; it's just that whether something is objectively real or not depends on the number of people who saw it. But you haven't even established that external objects exist in the first place, so your argument is non sequitur and begging the question. I suspect your reply will be something like, "If it looks, sounds, and feels like a duck, is it not reasonable to believe it is in fact a duck?" Well, you should know that practical considerations involving how we normally do things (e.g. using witness testimony to corroborate facts) are inadequate to substantiate robust philosophical claims. This debate would have been over hundreds of years ago if it were that easy.

It is real if real means established truth.

If we are looking at reality, whether or not things are lies or truths, if, per se, I am truthully solipsist or if the universe is logical, and other people are conscious. Then, it's beyond what's "established truth", it is a combination of real and unreal. Is the universe a simulation just for me I cannot see? Do I fragment this all from mind? Then we're looking at unreal mechanics? Are there any?

Let's call the two hypotheses as so: (1) for world as we perceive it; and (2) for brain in a vat.
One formulation of Occam's Razor is: Entities should not be multiplied without necessity.
In hypothesis (1), the entities are: A real world which we perceive.
In hypothesis (2), the entities are: A real world which we don't perceive + an illusion of the world we perceive, created by a machine in that real world.
Hypothesis (1) is composed of fewer entities, and is therefore simpler.

Now you argue that it is easier in (2) to create the illusory world, than in (1) to create a real world. But this omits the fact that in (2), a real world also exists, which includes the machine that creates the illusory world. And appealing to the Principle of Sufficient Reason, an effect necessitates a sufficient cause. The machine containing the information for the illusory world must exist in a world that is at least as rich in information.

It seems to me this statement can be viewed in one of two ways. (1) You are either making a claim about how we already do things (i.e. using witness testimony to corroborate facts), or (2) or you are concluding from your argument that philosophical realism holds. — Wolfman

Both. The witness testimony uses the PUP to determine the most reasonable story about the case. And that same rationale is used to determine the most reasonable claim about metaphysics.

Your premise already assumes that external objects exist; it's just that whether something is objectively real or not depends on the number of people who saw it. But you haven't even established that external objects exist in the first place — Wolfman

External objects must exist for us to have true or false perceptions of them. Also I am fairly sure Hume did not question the existence of external objects; and was only skeptical about their true nature.

This debate would have been over hundreds of years ago if it were that easy. — Wolfman

Unless all those debaters used that similar line of circular reasoning. :wink:

External objects must exist for us to have true or false perceptions of them. — Samuel Lacrampe

Yeah, whatever it is you're doing, it's not philosophy :roll:

But the point of (sincere) debate is to find truth. Proper rules of reasoning and debate (which includes burden of proof) is part of epistemology. You might as well say that the objective world does not care about epistemology as such, which is true, but would miss the point that the function of epistemology is to know the objective world. — Samuel Lacrampe

I don't really disagree with much of this, but I don't think you're going about the "search for truth" in quite the right way.

The first question of epistemology is "what can we know", and the second is "how do we know it". To answer these question, one has to establish a connection between a certain rule and knowledge. It's not sufficient to identify rules of thinking about the world. One must also establish why, by following these rules, we actually gain information.

So if you want to establish burden of proof as an epistemological principle for metaphysical questions, you'll have to justify the connection between the rule and metaphysical reality.

That's fine. Instead of "hallucination" let's called it "false perception", for which "false" means "not in conformance with reality". — Samuel Lacrampe

The problem is that this false perception may very well be normal, even unavoidable, for humans, and therefore your previous arguments do not work.

I don't believe so. There are only 2 categories of being in that sense: real and imaginary. E.g. a horse is real, a unicorn is imaginary. By "internal reality", I am guessing you actually mean "imaginary" which is the alternative to being real. — Samuel Lacrampe

So what about the colour red? Is it real or imaginary?

I still challenge this claim. Ethic is only properly speaking a science if it is objective; which means that goodness exists in reality. But if no goodness in reality, then no ethics. — Samuel Lacrampe

How would that be possible? Do you imagine there to be some actual rulebook hidden somewhere that is the "object" you could base morality on? The question of morality is "what should I do". How is that in any way connected to objects?

Anyways ethics was one example. Another one would actually be epistemology itself. Because if epistemology is about discovering the "objective nature" of the universe, then the truth criterion for that cannot be "accordance with objective nature". That'd be circular.

Similarly, there is no such thing as "physical reality" if we can know nothing about reality. Even if the physical is the result of a false but universal and consistent perception, we are then still claiming that this false perception exists in reality. — Samuel Lacrampe

I think you're essentially complaining about words here (i.e. this is just semantics). Whether or not you prefer to reserve the term "reality" for "objective" or "metaphysical reality" doesn't change whether or not the latter is connected to physics.

Of course not. But true thoughts are thoughts which content conforms to reality. And true thoughts are possible only if they follow the laws of thoughts. — Samuel Lacrampe

The just seems obviously wrong. If the criterion of truths is conformance to metaphysical reality, then if you have a collection of random thoughts, some of those could just happen to conform. The process used wouldn't matter. It would have to be the other way round: the laws of thoughts only discover the already existing true thoughts, and are defined by them.

Let's call the two hypotheses as so: (1) for world as we perceive it; and (2) for brain in a vat.
One formulation of Occam's Razor is: Entities should not be multiplied without necessity.
In hypothesis (1), the entities are: A real world which we perceive.
In hypothesis (2), the entities are: A real world which we don't perceive + an illusion created by a machine in that real world.
Hypothesis (1) is composed of fewer entities, and is therefore simpler.

Now you argue that it is easier in (2) to create the illusory world, than in (1) to create a real world. But this omits the fact that in (2), a real world also exists, which includes the machine that creates the illusory world. And appealing to the Principle of Sufficient Reason, an effect necessitates a sufficient cause. The machine containing the information for the illusory world must exist in a world that is at least as rich in information. — Samuel Lacrampe

I get what you mean. What you say amounts to the standard argument against the skeptic.

As for what I mean, let me begin by saying I accept that for there to be an illusion there must be the real. However, the real needn't be the whole enchilada - the entire universe, no?

Compare the following:

1. Minds exist + the whole real + the illusion

2. Minds exist + the whole real

3. Minds exist + part of the real (necessary to generate the illusion) + the illusion

2 is definitely simpler than 1 and that's your argument but what about 3? 3 would be more complex than 2 if and only if part of the real (necessary to generate the illusion) must be equal in complexity to the whole real in which case 3 would be identical to 1 and you win. Is this the case? Do we need the whole real to generate the illusion or will only a part of the real (necessary to generate the illusion) suffice?

Before you answers the above question, keep in mind that the illusion need not be of the whole real, thus can be simpler than the whole real and so only a part of the real will suffice to generate the illusion. Then minds and only that part of the real, necessary to generate the illusion need exist and the rest of the whole real becomes unnecessary complexity:

a) The illusion is less complex than the whole real. This is for the following reason:

b) Part of the real necessary to generate the illusion is less complex than the whole real

[Minds exist + Part of the real (necessary to generate the illusion) + The illusion] is less complex than Minds exist + The whole real.

Ergo, 3 (my choice - a universe with illusion) is far more parsimonious than 2 (your choice - a universe without illusion).

The only reason you'll find all this hard to digest is if you think 3 is the same as 1 or that the illusion we're talking about is of the real world which would require the part of the real (necessary to generate the illusion) to be as equally complex as the real whole but that isn't necessarily true. The universe we're familiar with, this universe, could be a simpler illusion, the work of an illusion generator, in a universe our minds actually exist in. If so, minds + the illusion generator is simpler than minds + the entire universe minds exist in.

Take the real universe as 100%, minds form 10% of this universe, and an illusion generator which is 40% of this universe that creates an illusion which is simpler = 20% of the real universe. Isn't (40% + 10% + 20% = 70%) < 100%? Isn't 70% of the universe less complex than 100% of the universe?

I know I've repeated myself more than I would've liked to but the point I'm making isn't so easy to put into words. Sorry.

So if you want to establish burden of proof as an epistemological principle for metaphysical questions, you'll have to justify the connection between the rule and metaphysical reality. — Echarmion

Sure. Aside from mathematics and pure logic, we never reach certainty for any other sciences. In all other sciences (metaphysics and others), the accepted position about a topic is the one that has not yet been refuted. We say that the position stands, that it becomes the prima facie, and that the onus of proof is on the other side. It is a good alternative to remaining agnostic about everything merely on the grounds that we do not reach certainty. Maybe we can afford to remain agnostic on some topics, but not all. See next paragraph as an example.

The problem is that this false perception may very well be normal, even unavoidable, for humans, and therefore your previous arguments do not work. — Echarmion

This topic of whether all perceptions are false or some are true, is a good example where we cannot afford to remain agnostic on the grounds that both hypothesis remain possible. We gotta live. We gotta pick a side. Enters the Prima Facie approach as per above.

So what about the colour red? Is it real or imaginary? — Echarmion

Hmmm.... That's a tough one. It's almost worthy of its own discussion. For now, I say real; as we cannot conceive something we have not experienced in the past. E.g. a blind man born blind cannot conceive the colour red.

How would that be possible? Do you imagine there to be some actual rulebook hidden somewhere that is the "object" you could base morality on? The question of morality is "what should I do". How is that in any way connected to objects? — Echarmion

The objective basis to ethics is values, ie that some things are good or bad in reality. E.g. I should do this because it is objectively good.

Another one would actually be epistemology itself. Because if epistemology is about discovering the "objective nature" of the universe, then the truth criterion for that cannot be "accordance with objective nature". That'd be circular. — Echarmion

Siding with Aristotle, the foundations of epistemology are first principles called the laws of thoughts. These laws are Deductive Reasoning (aka logic), Inductive Reasoning (aka stats), and Abductive Reasoning (aka Parsimony). As first principles, they are not founded on any other premises.

Whether or not you prefer to reserve the term "reality" for "objective" or "metaphysical reality" doesn't change whether or not the latter is connected to physics. — Echarmion

It does. Let me try again another way. We perceive a physical object. Either that object is real or not. If real, then we made a claim about metaphysics. If not real, then the explanation is the existence of a false perception. Then we still made a claim about metaphysics, namely that this false perception is real.

if you have a collection of random thoughts, some of those could just happen to conform. — Echarmion

Good point. Let me try again: Knowledge is achieved when the thoughts are true and justified, and correct justification must follow the laws of thoughts.

Sure. Aside from mathematics and pure logic, we never reach certainty for any other sciences. In all other sciences (metaphysics and others), the accepted position about a topic is the one that has not yet been refuted. We say that the position stands, that it becomes the prima facie, and that the onus of proof is on the other side. It is a good alternative to remaining agnostic about everything merely on the grounds that we do not reach certainty. Maybe we can afford to remain agnostic on some topics, but not all. See next paragraph as an example. — Samuel Lacrampe

But what do we do if there a bunch of conflicting hypotheses, neither of which can be refuted (in the sense of a falsification). Take the classic theism - atheism debate. Refutation really doesn't seem like a good fit for a host of problems.

This topic of whether all perceptions are false or some are true, is a good example where we cannot afford to remain agnostic on the grounds that both hypothesis remain possible. We gotta live. We gotta pick a side. Enters the Prima Facie approach as per above. — Samuel Lacrampe

But we only need working physics to live. We don't really need metaphysics. That is, we don't technically need to understand what it is we are predicting and explaining, only that our predictions are good enough. After all, the simulation hypothesis and similar thought experiments do not force us into inaction.

Hmmm.... That's a tough one. It's almost worthy of its own discussion. For now, I say real; as we cannot conceive something we have not experienced in the past. E.g. a blind man born blind cannot conceive the colour red. — Samuel Lacrampe

I am sure there have been plenty of discussions on this forum already :wink: . This is just a variant on the "hard problem": Red doesn't seem to be a physical property of anything (light has wavelength, but it doesn't have "redness") and yet it somehow is in our minds. And to make matters worse, there seems to be no way to confirm anyone else sees red the way you or I see it. It's subjective, but also real.

The objective basis to ethics is values, ie that some things are good or bad in reality. E.g. I should do this because it is objectively good. — Samuel Lacrampe

I don't want to make this a discussion about morality, but my question would remain the same. What is "objective goodness" even supposed to mean? A catalogue of good deeds? A definition? A divine judge?

Siding with Aristotle, the foundations of epistemology are first principles called the laws of thoughts. These laws are Deductive Reasoning (aka logic), Inductive Reasoning (aka stats), and Abductive Reasoning (aka Parsimony). As first principles, they are not founded on any other premises. — Samuel Lacrampe

Right, so would you call these principles "true" or something else?

It does. Let me try again another way. We perceive a physical object. Either that object is real or not. If real, then we made a claim about metaphysics. If not real, then the explanation is the existence of a false perception. Then we still made a claim about metaphysics, namely that this false perception is real. — Samuel Lacrampe

That seems to be a bit like the logic saying that atheism is a religion. Let's say there is a physical tree. It could be that there also is a metaphysical tree. It could be that the tree is a metaphysical dragon. It could be that the tree is a metaphysical rock. Saying "the tree is really (metaphysically) a tree" is a metaphysical claim. So is claiming it's really a dragon etc. What's not a claim is saying that "it might be a tree, but I don't see how you could ever find out". The latter would, at most, be a claim about epistemology.

Good point. Let me try again: Knowledge is achieved when the thoughts are true and justified, and correct justification must follow the laws of thoughts. — Samuel Lacrampe

Justified true belief. Yes I think that's fine. I don't actually think there is any true definition for truth, it can only be described by example. But I am fine with using this one.

Yeah I think I get what you are saying too, that in terms of total content that is existing in the real world and displayed in the illusory world at one time, (3) can have less total content than (2). But I don't think that "less content in the objects of explanation" translates to "lesser complexity of the explanation". I illustrate with an example.

I observe a house from the front side. Then I circle around to check that all 4 sides are fully built. I observe that no wall is missing. Kinda like this. I can draw 2 explanations.

(1) There are really only 2 walls existing, and a swift house builder just moves the 2 walls around as I circle around, to make it look like there are 4 walls.
(2) There are 4 walls.

One could argue that explanation (1) has less content in the objects of explanation (ie 2 walls + 1 builder as opposed to 4 walls). Yet clearly explanation (2) is the simplest in terms of explanation.

Yeah I think I get what you are saying too, that in terms of total content that is existing in the real world and displayed in the illusory world at one time, (3) can have less total content than (2). But I don't think that "less content in the objects of explanation" translates to "lesser complexity of the explanation". I illustrate with an example.

I observe a house from the front side. Then I circle around to check that all 4 sides are fully built. I observe that no wall is missing. Kinda like this. I can draw 2 explanations.

(1) There are really only 2 walls existing, and a swift house builder just moves the 2 walls around as I circle around, to make it look like there are 4 walls.
(2) There are 4 walls.

One could argue that explanation (1) has less content in the objects of explanation (ie 2 walls + 1 builder as opposed to 4 walls). Yet clearly explanation (2) is the simplest in terms of explanation. — Samuel Lacrampe

:ok: I wish you'd said something else though.

But what do we do if there a bunch of conflicting hypotheses, neither of which can be refuted (in the sense of a falsification). Take the classic theism - atheism debate. Refutation really doesn't seem like a good fit for a host of problems. — Echarmion

Are these frequent? Maybe just because some hypotheses haven't been refuted yet, doesn't mean they cannot be refuted. [Side note, I didn't think the theism-atheism problem was too hard; but that could be a conversation for another time].

But we only need working physics to live. We don't really need metaphysics. That is, we don't technically need to understand what it is we are predicting and explaining, only that our predictions are good enough. — Echarmion

That still depends on the metaphysical topic. Is it important to know that the perceived physical rock is metaphysically real? Indeed probably not. But moral values? Quite so. The answer should influence the behaviour of most people.

[...] And to make matters worse, there seems to be no way to confirm anyone else sees red the way you or I see it. — Echarmion

Occam's Razor. Boom. :wink:

What is "objective goodness" even supposed to mean? A catalogue of good deeds? A definition? A divine judge? — Echarmion

If you are asking what is objective goodness, it means that some things are good as a matter of fact, not a matter of opinion. If you are asking for the definition of objective goodness, then skipping straight to the answer of Aristotle without explanation (as it would be a long one), it is "a potentiality being actualized. And as actuality and potentiality are objective states of things, goodness in that sense is objective.

Right, so would you call these principles "true" or something else? — Echarmion

Truth being defined as "conformance to reality", calling these principles true means that applying them will give conclusions that conform to reality.

[...] The latter would, at most, be a claim about epistemology. — Echarmion

Right; saying "I don't know" is indeed not a metaphysical claim. But my point was that if saying "the perception is a false one", that is implicitly making the metaphysical claim that "a false perception exists in reality".