All the empirical objects that I perceive around me are structures of sensations: sensations of color, tactile sensations such as hot and cold, hard and soft, and rough and smooth. But sensations are supposedly manufactured in the brain, out of neural signals delivered from the sense organs. This leads to two questions: how do they get out there, into the real world; and if sensations are unreal --- they exist only as long as they are perceived --- and the real world is composed of sensations, is the real world really real?

I think the best place to begin is with the first sentence: "All the empirical objects that I perceive around me are structures of sensations." I think this confuses two things. The objects we perceive are things like tables, chairs, tin nickels and left-handed paper-hangers. And none of those things are structures of sensations. Now it may be that the way we perceive these things is by having various sensations, and it's also true that in some sense the sensations are manufactured in the brain, brought about with the causal assistance of the paper-hangers and such. But the machinery of perception isn't the same as what's perceived.

More generally, it's no surprise that we perceive things by way of stuff going on in our brains. But that stuff isn't what we see; it's what makes seeing possible.

So yes: the real world really is real (last time I checked). It's not composed of sensations, though sensations may be among the many things that make up the world entire.

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