It’s an odd statement to make. It seems obvious, and it is obvious. Every time you open your eyes, you can see a variety of objects. Not only that, but you can go over and feel the objects too. Even if you leave for a while, you can safely assume that everything you left behind still exists. There are literally more than a billion lifetimes worth of experiences that suggest that things actually exist, but even then, it is ultimately an assumption about the way the world works.
This is a problem that has troubled many minds. At its most basic, we have to take the mere existence of things as an assumption. There is no way around this. The problem is illustrated in Godel’s Incompleteness Theorems. In order for the world to make sense, we must assume a few fundamental properties. There are two that I want to reference specifically:
There is sufficient cause for everything.
These are only assumptions about the nature of the universe, but without them, nothing makes sense. I mean that in a very literal way. Logic itself breaks down if we can’t make these sorts of assumptions. If we can’t assume that things exist, then there is nothing to which we can attach any meaning. If we can’t assume that there is causality, then events happen at random. You couldn’t have any measure of control over what happens, and everything you do lacks meaning.
There are reasons for us to assume these things, which I will get into later. For now, I will simply say that I hope nothing here registers as particularly surprising to anyone. These seem like perfectly ordinary assumptions to me, which is why I am particularly troubled that my very own field of science is reporting its results in such a way that makes it seem like these fundamental tenets of logic aren’t true.