Eliezer Yudkowsky

in your mind.

You might indeed deduce all sorts of explicit descriptions of the airplane at various levels and even explicit rules for how your models at different levels interacted with each other to produce combined predictions.

And the way that algorithm feels from inside is that the airplane would seem to be made up of many levels at once interacting with each other.

The way a belief feels from inside is that you seem to be looking straight at reality.

When it actually seems that you're looking at a belief, as such, you are really experiencing a belief about belief.

So when your mind simultaneously believes explicit descriptions of many different levels,

and believes explicit rules for transiting between levels as part of an efficient combined model, it feels like you are seeing a system that is made of different level descriptions and their rules for interaction.

But this is just the brain trying to 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.

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.

The laws of physics do not contain distinct additional causal entities that correspond to lift or airplane wings the way that the mind of an engineer contains distinct additional cognitive entities that correspond to lift or airplane wings.

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 multi-level models are out there in the territory.

Understanding this on a gut level dissolves the question of how can you say the airplane doesn't really have wings when I can see the wings right there?

The critical words are really and see.