Strange

Think of buoyancy as an analogy: as air pressure pushes down on a balloon (or beer pushes down on a bubble) it rises rather than being pushed down. Because it has less mass than the background "field" (atmosphere/beer).

Because rubidium atoms have (positive) mass. They can be made to behave as if they had negative mass. In the same way a hole (absence of an electron) has an effective mass even though it doesn't exist. And, MigL was right, there is no such thing as negative currency.

I would have thought that anyone on a scientific forum, with n understanding of science, would assume that is what was meant. We can't hedge every single statement around with "seems", "as far as we know", "is not consistent with the evidence", etc

Space doesn't "suck light". The reason empty space cannot be seen is because there is nothing (or not enough) to reflect light. There are plenty of things that are "invisible" (as transparent) as air. Space is not an object, it is just the measure of distance between things. We now very well from theory and observation that the commonest element in the universe is hydrogen. It make up about 95% of the universe. You can say that again.

Nonsense.

I think that is the last of the 9 billion names of God: https://en.wikipedia.org/wiki/The_Nine_Billion_Names_of_God

But the same is true of a (simpler) tetrahedron or an icosahedron or a sphere. So there is no reason to visualise it as a cube. It doesn't require a boundary. If the volume is infinite, for example. But even if the universe is finite, it is assumed to have no boundary. (This is easier to imagine in 2 dimensions, the surface of a sphere, for example. Or a cube, if you must.)

To try and explain why science does not deal with "reality". It deals with things our senses tell us. That is all there is to it. You cannot know anything beyond what your senses tell your (or, more, accurately what your mind tells you that your senses say). Everything you know, all the information you have, is in your mind and created by your mind. Why not? How would you tell if there were something out there beyond what your mind tells you? Well, if you are defining "instance" to mean a visual stimulus perceived by a being, then there are an unbounded number. That is not what I understand "instance" to mean.

Ask someone with schizophrenia. But it doesn't matter "how" it can happen. There is no independent evidence, beyond your own senses and mind, for the existence of anything (including other people). This is a straw man (or straw snake) argument. You invent a type of hallucination that doesn't correspond to reality and then claim it proves that hallucinations do not behave like reality. What about a hallucination of a snake that slithers out of the grass and then runs away when you approach it. It behaves just like a real snake. Also, we are not talking about drug-created hallucinations. They were just introduced to refute the claim that people cannot have hallucinations that affect all sense consistently. They obviously can, whether due to drugs or psychosis. But if you see a snake, you can only compare it to your idea of what a "real" snake should do based on your memories, which were created by your mind. So there is no reason that any snake you see (which is, therefore, a creation of your mind) would not behave exactly like your memory of other snakes created by your mind.

But the Earth that is studied may not have any existence beyond our minds. Perhaps because I am not. I don't know what the existence or non-existence of gods has to do with the subject. What difference does it make, whether you believe in a god/creator or not? Either way, you know nothing beyond what your senses tell you.

It can. But there is no reason to think it is correct. Actually, it can tell us a lot about what the star is doing now (in most cases). Unless you invoke the sort of reality you don't like, where stars can magically change their behaviour in defiance of known physics. There are a few exceptions. For example, Betelgeuse could have already gone nova (or could do so tomorrow) and we wouldn't know. But we only know that is a possibility because of science. Philosophy is not bound by the sort of "reality" that you think science describes and so is free to say anything at all about distant stars ("they are the eggs of space unicorns, and that star 4 light years away has recently hatch and will no long be visible in 3.5 years time"). No, there is only one star. (In reality, even if there are two in your mind.) Who knows. The nice thing about philosophy is that you get to choose the answers to these questions. (And religions lets someone else choose them for you! ) (If it reassures you at all, I am a "naive realist"; I believe that reality is pretty close to what we observe. But I know this is an irrational and completely unsupportable belief.) No I don't. For all I know, you could be a hallucination.

Indeed. And most people are avoiding that - partly by talking about science. That is correct. So science employs a philosophy of methodological naturalism that assumes that what we measure has some sort of independent existence and there are no supernatural effects beyond that. But that doesn't mean it is true. Science would work just the same, whatever the "true" nature of reality. The universe could have been created 5 minutes ago complete with our memories, fossils, 13.8 billion year old radiation, etc. Or it could be a simulation by hyperdimensional white mice. Or a figment of your imagination. And our science would work equally well in any case. The models work because they are consistent with our observations. Our observations do not necessarily correspond to any sort of reality.

That doesn't seem any different from your other argument. It also the fallacy of begging the question: if you accept that there are other conscious individuals, then this disproves solipsism. But there is no evidence, outside of your own mind, for other conscious individuals. Therefore there is no evidence against solipsism. 1. It is not a fact that you have free will. Depending on which definition of "free will" you uses, this ranges from impossible, to implausible to meaningless. 2. Even if you appear to have free will, it could be an invention of your mind. It says nothing about the existence of anything outside your mind. 3. Solipsism does not require an "ultimate mind or consciousness" (whatever that means); only that all the other conscious individuals you perceive are creations of your own mind. At an extreme (idealism) nothing exists except what is crated by your mind.

Nope. Reality is inherently unknowable. All we can know is what our senses tell us (actually, the idea that we have senses could be an invention of our mind!). You seem to be missing the key point about science which is that it tests its models. (And that works, whatever the nature of reality, or even if there is no such thing.)

Science has nothing to do with truth. It creates models that describe and, to some extent, explain what we perceive around us. That does not depend on the existence of any external reality (see also, the regular threads about living in a simulation).

That "proof" only exists inside your own mind. As does everything you know about "reality". Anything you think of as independent evidence of the existence of others is also purely in your own mind. You have no access to reality (or the existence others) except through your senses; in other words, what your mind tells you. And we know that often deceived you. So it may seem obvious that reality exists "out there" and that there are other people, but it is just your mind telling that! The words you should have highlighted were ones like "assumin" and "indicate" and others showing a lack of certainty. Also, as you should know, all scientific statements of "fact" should be (and implicitly are) accompanied by statements such as: as far as we know; current evidence indicates; consistent with our best models; subject to change; etc

Nope. Because it could all be happening entirely in your head. There may be no other people (and no other reality) other than what is in your head. Absolutely. Science can say nothing about reality. All it can do is describe what we observe. (And, note that that works equally well even if there is no external reality and it is all created by your mind.) Not only can science not say anything about reality, but nothing (other than blind faith) can say anything about reality. It might be. Or the external reality might be completely different. Or it may not exist. How would you know. You can only know what your sense tell you. You have no independent way of checking they are "true". That is a very dangerous (and unscientific) approach. One thing we have learned from science is that our senses (and memories) are very, very unreliable. If you think your senses are more important than objective reality, does that mean that you think the two squares in this image are actually different colours even though, objectively, they are the same? You appeared to express disbelief that people could experience hallucinations that affect more than one sense (in a consistent way). Which is obviously wrong.

Oh come on. Really? You don't believe that people such as those with schizophrenia who see people that aren't there and talk to them, are not having a consistent visual and auditory hallucination? They can probably smell and touch the person as well. FFS. And I can assure you that certain chemical substances that cause hallucinations can cause you to both see and hear things that do not exist. But even if that didn't actually happen in the world (we think) we live in, that is irrelevant. From the point of view of a logical(*) argument it is possible that hallucinations can create a completely false reality that cannot be detected or tested in any way. (*) And I mean logical in the strict philosophical/mathematical sense, not "oh, that doesn't seem right to me" sort of logic (aka common sense).

Nope. Because the "other person" could be a creation of the first person's mind. (As indeed, could the first person.) So sensing them, and communicating with them to compare models could all happen in one persons mind.

Exactly. (Although I think it is a bit silly to use the word "god" to describe this.) And maybe that is why invoking god is a mistake. It doesn't matter whether an individual knows or beliefs they are the only thing in the universe, it is impossible to prove they are not. You are saying that a god would know. But we aren't talking about god, we are talking about you or me. Or you can say that "common sense" tells you that it is wrong. But that common sense could be (and, in reality, usually is) an illusion as well. You can assume that. But there is no evidence for it. And no way of proving it. That is all I am going to say on the matter. There is another forum where the discussion on the nature of reality has been (voluntarily) limited to one thread which has been going for what seems like a million years and it is just repeating the same arguments over and over.

But maybe that "other person" (and their confirmation) is an illusion as well. Solipsism may seem to be a rather foolish idea but it can't be disproved and, as we can see from this discussion, it does have a role in teaching critical thinking.

Your imaginings and hallucinations are worthless without evidence.

Well, you are mixing up the concepts of validity and soundness, but you are basically correct here. Unfortunately, you are not applying those standards to your own opinions. For example, you appear to dismiss the philosophy of idealism as wrong with no logical argument at all.

Sigh. Stop repeating that without thinking about it. https://en.wikipedia.org/wiki/Cogito_ergo_sum#Criticisms And you certainly don't know for sure that your fingers exist. They could be a product of your imagination. (As could the entire universe, including the embers of this forum.)