Hi grey_whiskers! That may be the true operation of the rock; but the rock didn't throw itself. "I" did.
Why do you think the brain is "*thinking*, *perceiving*, or *doing*...?" It may be that its role is that of the rock, not that of the rock thrower.
If we want to find out what's what, then perhaps the question should be left open for further investigation, rather than reduced or closed, based on our current understanding of the problem. JMHO FWIW
Hence when you get hit with a rock, in the eye, you feel pain. Someone on the sidelines might note the vascular damage, the cells being pulverized, the biochemical and molecular attempts by the body to mediate the damage.
Both are true, but you are only immediately conscious of one.
But just because pain is "subjective" and cannot be quantized in the way beloved by scientists does not make it "unreal"--it just means their instruments cannot differentiate it; whether because the instruments are not yet suited, or not powerful enough, or whether there is a "ghost in the machine" is yet unknown...
Cheers!
'I' is also objectified. Putting it in language as the first person does not automatically make it subjective.