Thank you for the kind words. I’ll now avoid trying at all to recapture that out of fear of failing.
Shall we call you a non-Platonist? Or perhaps you want to keep the Hitchenesque “anti-“. So that you are against platonism and might be seen, after death, faced with Plato himself in the caves of shadows, giving him the right old middle finger.
Non-Platonist seems more reasonable to me than full Platonist, and that’s even after a good decade studying and appreciating the beauty of maths and physics. I’m not sure where I fit exactly, but I think we can lock it in. I agree that to exist is a distinguished badge and that matter and physical forces between them falls solidly in that camp.
The best definition of physical as I can see is that it interacts with things and can be detected. This includes the above list of things and nicely excludes things like God and meaning.
But I do feel an alluring pull, but not out of a sense of mysticism or self-effacedness. You see, for things that don’t exist, theories tend to share many properties with things that do exist: they affect the world, they can be independently discovered (or invented), they’re detectable and they persist (in their form or truthfulness). Whereas some things that definitely exist fail some of these tests. Consider the 2,325,462,537,437,235th atom created in the universe. It is physical and we don’t argue it exists, but it can’t really be discovered and its effect on the world is ignorable. It may as well not exist.
Remember when Hannibal Lector ate a guy’s brain while talking to him? As the brain is eaten, its constituent dead atoms are dispersed and the non-Platonist, the whole while is unconcerned with whether brain exists or ever existed. But a semi-Platonist would see a brain, then after a short amount of time would see no brain, just a dead collection of atoms. But at some point something from the universe is removed and will have irreversible flow-on effects.
So in this view existence is a sort of clumping. A scale-based definition that traces out a consequential object in the world. One way to formalise this is to again refer to Deutsch. The things that are consequential would be the emergent objects that an explanation employs.
Let’s consider atomic theory. You’d say it (the theory) doesn’t exist but it does persist in truth, and it continues to be found when people look for it. It also has a real physical effect: it changed the lives of most people on Earth, and will continue to as humanity progresses. We physically modify the universe using the idea as much as we use the physical tools.
This is a wonderful position that puts intelligences (people) back to the centre of the universe. To fit with your analogy they’re the landmarks that sum up the territory, employed by the map to make it meaningful. (Let me know if I’m actually stumbling onto an existing philosophical theory won’t you?)
Information is a great example. It “exists” not in atoms themselves but in the configuration of these physical things. Whether it be holes in cards or the alignments of magnetic domains, the configuration has a real effect on the world. The configurations of atoms in magnetic tape in nuclear silo can have a fucking massive effect for things that don’t exist. The extant particles are interchangeable, replaceable, fungible, ignorable.
You can always say that objects or even theories are, at bottom, merely combinations of effects of quarks and forces. However the presence in the universe of something like a brainwave monitor then must only be described in terms of an astonishingly complicated sequence of deterministic knock-on effects from the beginning of the big bang. No intelligence in the universe could ever trace this history. These effects, and the existence of things like brainwave monitors are then unaccounted for. The universe to a non-platonist is composed of quarks, forces and impenetrable mystery. So I tend to think it’s more true to think of the universe in terms of the things that make it up. To sum it up while you believe only matter exists, I’m thinking all that matters exists.
Appropriately enwrapped,
Mat