Quantum Gravity’s Time Problem

There's a wikipedia article on that, of course, and it's not so bad.

https://en.wikipedia.org/wiki/Problem_of_time

The structure of the the paragraph you quoted and the one following it is similar to the first two long paragraphs under the "Proposed solutions to the problem of time" section of the wikipedia article.

There is a bit more here:

https://en.wikipedia.org/wiki/Canonical_quantum_gravity#The_...

and a technical overview in the first section of https://arxiv.org/abs/1009.2157

I wrote "seems", because I found it hard to focus on an article whose second paragraph is a grotesque of General Relativity and in subsequent paragraphs brings in a not especially clearly related set of links to the author's previous articles on the recent Verlinde paper on emergent gravity and the amplituhedron, among others. :-(

In case of solipsism you experience a universe around you but there seems to be nothing you could use to decide whether you are experiencing an independent outside universe through your senses or whether your mind is just hallucinating this whole outside universe.

In case of the universe simulation you experience a universe around you but you have no a priori knowledge what a real universe and what a simulation of a universe is supposed to look like, you seem to be stuck in more or less the same place as with solipsism.

You should start to associate causation to patterns in your experience, and observe carefully that patterns. Those patterns behaviour are not decided by you, so, by definition, they are outside your mind.

I think mind is probably not the right word here because it has the connotation of control, brain might be the better choice because there are things going on you can not control (ignoring whether you actually have any control to begin with). It may have not been clear from my first comment, but I was especially referring to metaphysical solipsism, denying the existence of an independent outer reality.

Simulation argument has serious experimental issues, but I would not discard it yet. Maybe we can think of something.

Personally I just don't think about it for the moment. There is surely the possibility that we make progress one way or another, but every time I try thinking about it, it leads nowhere. Maybe one day we discover the fundamental laws of physics, logical self-consistent and the only self-consistent laws of physics possible. With mathematical proof. Do we now know that our universe is real, it is after all nothing less than the only way it could ever have been?

Or did the simulator just mess with us again? We could be using inconsistent logic all day long, writing wrong mathematical proofs and be teaching them to the next generation in our universities. But just before someone realizes the error, just after we observed the contradicting consequences of our wrong reasoning, the simulator erases the relevant memory and life goes on as if nothing happened.

Unless somebody wants you to find out, you will never find out. The potential enemy in this scenario is just so powerful, you can not win.

I agree with you that from the point of view of testability both are very similar, but, in my view, from the point of view of logic reasoning are almost the opposite.

Solipsism is just bad reasoning or, at most, a semantic trick: I define my mind as everything there is out there, so, obviously, everything is in my mind. But we have science, precisely, to try to understand what it is out there, and "out there" means outside of our minds.

On the other hand, you arrive to the simulation argument by deduction. That's what, testability apart, make it interesting. The reasoning is: if a simulation is possible, then, many are possible. If there are many simulations in the universe, what is more probable? to be in the universe or in a simulation?

I agree that we don't know what to do with that, but you have to recognize that it's a damn good trick of logic.

1. attempt to create a simulated universe 2. make predictions about our universe based on the hypotheis

I would not rule either of these out as futile.