Here's a thought experiment that may illuminate some of the deepest questions of metaphysics...

First, any given configuration in Conway's Life (hence CL) can be said to exist regardless of whether it is being currently executed (or simulated) in on some external physical machine. That's why we say that we "discovered" rather than "invented" interesting configurations within CL. So the existence of anything within the CL universe independent of its simulation... "running" a particular configuration on our computer is just a way for us to visualize this existence. CL configurations exist in kind of Platonic parallel universe of pure math or information, and a software implementation of CL is a window into that Universe.

Now let's assume for a moment that AGI is possible, i.e. that any turing machine can become a conscious mind (given the right software, enough processing power, and time). Then that means there are minds in the CL universe... they exist, regardless of whether we are simulating them or not. But since the CL configurations in which they exists are enormously complex, we may never actually simulate any of them. Yet they exist, and if we do "discover" one of them we could run it multiple times, always with the same result... that would be just like window into that mind's existence that, like a movie, we can play again and again, but the existence is independent of our running it.

Now let's try to put ourselves for a moment into one of these minds... to it, its world is physical, it can be sensed and manipulated. It is "real" like our own world is real to us, but again, that reality is independent of the CL configuration ever being simulated. It is a mathematical reality that appears hypothetical to us, but it has physical form to the minds within, regardless of being simulated; our simulating any CL configuration only makes it observable for us, it has no bearing on its internal reality. So now we have a very useful distinction between the terms "existence" and "reality"... the former is universal, the later refers to the perspective of a mind.

So, what does all this mean with respect to our own reality? Well, first of all it means that asking whether our own reality might be a simulation (as some philosophers and even physicists have done in recent years [1]) is really kind of irrelevant. Our existence is in some sense just as mathematical as CL (at least if the universe is in any sense deterministic), but that math doesn't need to be simulated or executed by any external machine for it to be real and physical to us. In other words, "it from bit" [2].

Secondly, it suggests that we may be able to find a mathematical way of determining whether or not we can ever truly know the fundamental nature of our reality... all we have to do is figure out if a CL mind can discover the rules of the cellular automaton in which it exists.

Thirdly, it means that everything exists, every imaginable type of "universe" has existence [3], but only those which can give rise to minds have reality, because "realness" is a property of mind, not of universes.

[1] https://www.scientificamerican.com/article/do-we-live-in-a-s...

[2] See John Wheeler's 1989 paper with this title

[3] I.e. there is a "level 4" multiverse according to Max Tegmark's hierarchy of multiverses; https://space.mit.edu/home/tegmark/multiverse.pdf