But this is just the brain trying to be efficiently compress an object that it cannot remotely begin to model on a fundamental level. The airplane is too large. Even a hydrogen atom would be too large. Quark-to-quark interactions are insanely intractable. You can't handle the truth.

Can you handle the truth then? I don't understand the notion of truth you are using. In everyday language, when a person states something as "true", it doesn't usually need to be grounded to logic in order to work for a practical purpose. But you are making extremely abstract statements here. They just don't mean anything unless you define truth and solve the symbol grounding problem. You have criticized philosophy in other threads, yet here you are making dubious arguments. The arguments are dubious because they are not clearly mere rhetoric, and not clearly philosophy. If someone tries to require you to explain the meaning of them, you could say you're not interested of philosophy, so philosophical counterarguments are irrelevant to you. But you can't be disinterested of philosophy if you make philosophical claims like that and actually consider them important.

I don't like contemporary philosophy either, but I would suppose you are in trouble with these things, and I wonder if you are open to a solution? If not, fine.

But the way physics really works, as far as we can tell, is that there is only the most basic level - the elementary particle fields and fundamental forces. You can't handle the raw truth, but reality can handle it without the slightest simplification. (I wish I knew where Reality got its computing power.)

But you haven't defined reality. As long as you haven't done so, "reality" will be a metaphorical, vague concept, which frequently changes its meaning in use. This means if you state something to be "reality" in one discussion, logical analysis would probably reveal you didn't use it in the same meaning in another discussion.

You can have a deterministic definition of reality, but that will be arbitrary. Then people will start having completely pointless debates with you, and to make matters worse, you will perceive these debates as people trying to unjustify what you are doing. That's a problem caused by you not realizing you didn't have to justify your activities or approach in the first place. You didn't need to make these philosophical claims, and I don't suppose you would done so had you not felt threatened by something, such as religion or mysticism or people imposing their views on you.

This, as I see it, is the thesis of reductionism. Reductionism is not a positive belief, but rather, a disbelief that the higher levels of simplified multilevel models are out there in the territory.

If you categorize yourself as a reductionist, why don't you go all the way? You can't be both a reductionist and a realist. Ie. you can't believe in reductionism and in the existence of a territory at the same time. You have to drop either one of them. But which one?

Drop the one you need to drop. I'm serious. You don't need this metaphysical nonsense to justify something you are doing. Neither reductionism nor realism is "true" in any meaningful way. You are not doing anything wrong if you are a reductionist for 15 minutes, then switch to realism (ie. the belief in a "territory") for ten seconds, then switch again into reductionism and then maybe to something else. And that is also the way you really live your life. I mean, think about your mind. I suppose it's somewhat similar to mine. You don't think about that metaphysical nonsense when you're actually doing something practical. So you are not a metaphycisist when you're riding a bike and enjoying the wind or something.

It's just some conception of yourself which you have, that you have defined as someone who is an advocate of "reductionism and realism". This conception is true only when you indeed are either one of those. It's not true, when you're neither of those. But you are operating in your mind. Suppose someone says to you you're not a "reductionist and a realist" when you are, for example, in intense pain for some reason and are very unlikely to think about philosophy. Well, even in that case you could remind yourself of your own conception of yourself, that is, you are a "reductionist and a realist", and argue that the person who said you are not was wrong. But why would you want to do so? The only reasons I see are some naive or egoistic or defensive reasons, such as:

• You are afraid the person who said you're not a "reductionist or realist" will try to waste your time by presenting stupid arguments according to which you may or may not or should or should not do something.
• You believe your image of yourself as a "reductionist and realist" is somehow "true". But you are able to decide at will whether that image is true. It is true when you are thinking in a certain way, and false when you are not thinking that way. So the statement conveys no useful information, except maybe on something you would like to be or something like that. But that is no longer philosophy.
• You have some sort of a need to never get caught uttering something that's not true. But in philosophy, it's a really bad idea to want to make true statements all the time. Metaphysical theories in and of itself are neither true nor false. Instead, they are used to define truth and falsehood. They can be contradictory or silly or arbitrary, but they can't be true or false.

If you state you to regard one state of mind or one theory, such as realism or reductionism, as some sort of an ultimate truth, you are simply putting yourself into a prison of words for no reason except that you apparently perceive some sort of safety in that prison or something like that. But its not safe. It exposes you to philosophical criticism you previously were invulnerable towards, because before you went to that prison, you didn't even participate in that game.

If you actually care about philosophy, great. But I haven't yet gotten such an impression. It seems like philosophy is an unpleasant chore to you. You want to use philosophy to obtain justification, a sense of entitlement, or something, and then throw it away because you think you're already finished with it - that you've obtained a framework theory which already suits your needs, and you can now focus on the needs. But you're not a true reductionist in the sense you defined reductionism, unless you also scrap the belief in the territory. I don't care what you choose as long as you're fine with it, but I don't want you to contradict yourself.

There is no way to express the existence of the "territory" as a meaningfully true statement. Or if there is, I haven't heard of it. It is a completely arbitrary declaration you use to create a framework for the rest of the things you do. You can't construct a "metatheory of reality" which is about the territory, which you suppose to exist, and have that same territory prove the metatheory is right. The territory may contain empirical evidence that the metatheory is okay, but no algorithm can use that evidence to produce proof for the metatheory, because:

• From "territory's" point of view, the metatheory is undefined.
• But the notion of gathering empirical evidence is meaningless if the metatheory, according to which the "territory" exists, is undefined.

Therefore, you have to define it if you want to use it for something, and just accept the fact that you can't prove it to be somehow true, much less use its alleged truth to prove something else false. You can believe what you want, but you can't make an AI that would use "territory" to construct a metatheory of territory, if it's somehow true to the AI that territory is all there is. The AI can't even construct a metatheory of "map and territory", if it's programmed to hold as somehow true that map and territory are the only things that exist. This entails that the AI cannot conceptualize its own metaphysical beliefs even as well as you can. It could not talk about them at all. To do so, it would have to be able to construct arbitrary metatheories on its own. This can only be done if the AI holds no metaphysical belief as infallible, that is, the AI is a reductionist in your meaning of the word.

I've seen some interest towards AI on LW. If you really would like to one day construct a very human-like AI, you will have problems if you cannot program an AI that can conceptualize the structure of its own cognitive processes also in terms that do not include realism. Because humans are not realists all the time. Their mind has a lot of features, and the metaphysical assumption of realism is usually only constructed when it is needed to perform some task. So if you want to have that assumption around all the time, you'll just end up adding unnecessary extra baggage to the AI which will probably also make the code very difficult to comprehend. You don't want to lug the assumption around all the time just because it's supposed to be true in some way nobody can define.

You could as well have a reductionist theory, which only constructs realism (ie. the declaration that an external world exists) under certain conditions. Now, philosophy doesn't usually include such theories, because the discipline is rather outdated, but there's no inherent reason why it can't be done. Realism is neither true not false in any meaningful and universal way. You are free to state it to exist if you are going to use that statement for something. But if you just say it, as if it would mean something in and of itself, you are not saying anything meaningful.

I hope you were interested of my rant.