Is the Universe fake ?

If it is, then we'd all have to be in in it. I'm not, ergo the notion is daft.

Reframe the question. How do we know the universe isn't a fake?

Endacl suggests that we know this because, if the universe was a fake, "we'd all have to be in on it". And each of us knows that we ourselves are not in on it.

But it's not obviously true that, if the universe is a fake, we'd all have to be in on it. I think endacl is assuming that, if the universe is a fake, we faked it, but that doesn't necessarily follow. Hypothetically, our consciousness could be the creation of an advanced artificial intelligence program, and all our sensory inputs could be simulations, generated by the same program. In that scenario, we would not be aware that our sensory inputs were simulations; we would assume they were real.

One of the foundational assumptions of the scientific method is that our sensory inputs do, in fact, correspond to objective reality. This is a necessary element of the scientific method because if our sensory inputs don't correspond to objective reality we can never learn anything about objective reality from experimentation or empirical observation. And it has to be an assumption because, quite simply, we have no way of proving it to be true. Any attempt to prove it to be true by observation or experimentation is, obviously, a circular argument.

So, we may not believe that the universe is a simulation, but I'm not sure that we can prove that it isn't. But I think all this does is to highlight something that the philosophers of science have always known. All epistemological methods depend on axioms - unproven, unprovable assumptions. The notion that our perceptions of the universe correspond to an objective external realilty is one of the axioms that underpins the scientific method.

Balf wrote: »

Surely even that's denied to us. Does the current state of scientific knowledge suggest there's only one objective reality? Does the current state of scientific knowledge suggest that sensory inputs are reliable?

No, it doesn't. In fact, it can't. On the assumption that there exists at least one objective reality, and on the assumption that our sensory perceptions reflect that reality with some degree of reliability (and on a few other assumptions that we needn't specify here) then the application of the scientific method can tell us a good deal about that objective reality. But the scientific method can't be used to validate it's own foundational assumptions (because it's useless for any purpose unless those assumptions are true).

So we don't know that there exists an objective reality, or only one objective reality, or that our sensory perceptions reflect it reliably. At best, we just believe these things. And, on the whole, it's a belief that works out fairly well for us (as far as we can tell).

I think that guy on Horizon, what's his name?, Brian Cox, is running the virtual reality computer simulation. How else would he be on the television every night. Every sentence he utters is from a different mountain top. How else could he do that?