1. The world is what it is
It's widely considered that juggling is hard. And it gets harder when you're juggling atop a shaky platform sitting perilously on top of a ball. While simple enough, it's an object lesson in how doing anything gets tougher if the underlying strata is unstable. And in the same vein, it's difficult to create a self coherent philosophy in a world that doesn't have locally coherent rulesets.
And that's where we begin. With the observation and assertion that there does exist an objective reality, and it's roughly uniform and predictable across most human space-time-scales. Because if there isn't, then what's the point. We might all be brains in a vat, of supported by friendly demons, but since in that scenario creating predictions about the world is pointless anyway, we might as well proceed on the assumption that what we see is how things are.
But then the second problem. Yes, there is a world, and yes there is an objective truth corresponding to the world, but as can be evidently seen, not everything in the world is uniform. Perfect uniformity in a substrate is an unstable equilibrium. A small deviation in any direction, due to any randomness in any component, will create rippling effects that creates clusters in the presence of any feedback loops.
For example, with gravity as an attractive force, we see galaxies and stars and planets. With businesses we see geographic clusters (ice cream shop effect), interpersonal networks (bacon), and so on. Maybe the entire way of thinking is elucidation of an idea that didn't need further examination, but I like that there's an answer to the question of why everything isn't perfectly uniform.
Going a little bit more esoteric, if we think of "things" as we see them, it's also kind of sensible that they represent buckets of properties which agglomerate around that central concept. A chair is wooden, with three to four legs, somewhere to rest one's back, of a particular shape, with or without armrests. Is there a platonic chair these ideals come from? Difficult to say, since if there is then that platonic space needs to have a fractal like existence with platonic objects all the way down. But if I were to take the back off, and make the base a little bigger, we could reframe the object as an ottoman, or a stool, or one of another fifty incomprehensible names that I'm sure I missed out.
A collection of properties that's generally accepted is the name for an object.
But it also follows that if a cluster of properties is what defines a "thing", then the existence of such a "thing" is, by definition, fuzzy. There is no reason to think one collection is superior to any other.
Let's assume a mass of marbles, piled into a lovely small heap. Multiple marbles of multiple colours, lined in pretty lines. If we were to guess how to keep adding marbles to make it into a small pyramid instead, it would need the addition of more marbles in the right places, placed just so. But whichever way you arrange the marbles, at different points they will all tumble over. So if we were to make a science of heap-to-pyramidification, we could create multiple theories. One could be that there are specific combinations of number of marbles which helps bring about the desired transformation. But any theory here would be like the theory of epicycles, interesting and complex and wonderful, but ultimately doomed to becoming a curio. All the relevant interaction happens at the level of the marbles here, and not at heap-subunits.
Just like that, in our world, the interactions affect each other through rules defined at the lowest level, and other emergent rules that come about at the highest level. This emergence creates phenomena that we see at our level, and presumably at higher and lower levels as well, though we might not see those due to restrictions in size (galaxy-wide movements) or time (changes measured in millennia).
But for the purposes of this architecture we're trying to build, the key is that there exists a latticework of characteristics that agglomerate together to form objects, which have characteristics of their own, and in that causal-web created through their intricate dance somewhere arises the reality we see in front of us. Deconstructing it directly though is impossible, because the sheer number of ways in which things can combine and recombine to produce an outcome means that the causal-web is much harder to traverse all the way down.
There's an argument that's popular both amongst stoned college students and existential risk philosophers, discussing in great detail and multiple books whether we live inside someone else's simulation. Written in rather riveting detail by Nick Bostrom, it revived, or kickstarted if you prefer, a whole industry devoted to thinking about it. There was an older movement that tried to create something called holographic theory, which aimed to extend Plato's cave and show us that telepathy and miraculous healing are artefacts of this odd projection. That particular movement didn't seem to take off much.
But with the simulation argument there's a new resurgence. The core argument is simple, and mathematically beguiling. If compute power and our ability to "simulate" them as in a video game keep increasing, eventually we will get to a point where simulating human beings will become possible. If it becomes possible, at some point it will become relatively trivial in terms of energy expenditure to do. And if that happens, then there will be multiple simulations running of their history, i.e., us. And if you imagine billions of such simulations running, the chances that we aren't in one of them is vanishingly small.
One this is for sure. Just like the Drake equation, it messes with our perception of probabilities. Whether we are really living inside the matrix or not seems like the kind of question that is exceptionally important to answer. And speculations like this go a long way back, to Descartes trying to figure out if his senses were lying to him, to Plato's allegory of the cave.
Part of the answer is of course, testability. However that runs into the problem that if someone has the ability to run such realistic simulations about our world, including such large ranges of uncertainty regarding string theory and the Large Hadron Collider and light cones, surely they would also be able to block any testing we could come up with. So that entire line of inquiry essentially ends up being rather circular.
But another key question is what, if any, difference this makes. Is it effectively an irrelevant drama? Because even if it is correct and we discovered that we are in fact living in a high-fidelity simulation, it's not clear what needs to change about our life or even our metaphysics. We could call our simulators our Creator, and if it is truly successful it might create a new religion that everybody would follow, competing for headspace with the existing ones. And maybe the philosophers who spend their life arguing about life's purpose would have to slightly shift it to make it about our Creator. And away we go.
The difference with playing a game vs simulating reality is that you are no longer doing things as if there's an underlying reality, but actually dealing with something that claims to be part of the substrate of that reality. When we talk about gluons and quarks, we can credibly claim that they, in some sense, exist. If it turns out that the Standard Model is what is needed to simulate the universe, then what that effectively means is that our ability to understand our environment and the rules that bind the world we live in are explicable, which itself would be a relief to most scientists, and that there is at least some level of computational irreducibility in the simulation.
So far, so mind boggling. But the key part that emerges from the confusion is that we have to assume a fixed substrate of something around us. Something that is explicable, or at least that presents according to some rules. And that's an essential component to build anything atop.
If I were to write a science fiction novel, set somewhere far enough away from our planet and solar system, or maybe even out of our light cone, I could factually pretend that the laws of physics are different there. While we all believe that this isn't the case, it's not an empirical belief. It's because that allows us to create a set of predictions that we can build on, or at least test, and without that assumption (if only in a more limited sense), we would flounder. If that were not the case, we could all play our own language games amongst each other, and feel virtuous, beautiful and intelligent when a bon mot vanquishes our foes. But the potential for there to be an answer, even if it is complex and unintelligible, is better than the alternative. It allows us to build our edifice above a firm foundation.