To move and to react are not two different kinds of action.

To define their difference simply as 'physical versus mental' is insufficient, as this classification merely acknowledges the division while leaving its fundamental nature unresolved.

They are not simply distinct types; they are fundamentally heterogeneous and share no common conceptual ground. They are alien to each other.

One is there, the other - nowhere. One is me, the other - it.

The fact that I can - or am disposed to - react is trivial. The fact that I can conceive of, rather than merely encounter, reaction is an utter riddle.

If 'conceive of' merely meant 'decipher', there would have been no problem.

But no one, alas, deciphers reaction (or intention), other than in encountering it (to encounter is indeed to decipher).

When one conceives of... something, one does something altogether different. But what?

What does one do when he/she conceives of something that is nowhere and is me or you?

What is it that we wish to understand in philosophy?

Cognitive encounters with the world yield many questions.

Cognitive encounters with cognitive behavior seem to yield only the same kind of questions.

We wish to understand why (which doesn't mean we'll succeed).

We proceed.