Rational powers—abstract reason and free will—are not caused by the body or brain—they interact with matter but are not themselves generated by matter. They are immaterial powers of the human soul.
However, and this is the important point, the intellect and will are dependent on the sensitive and vegetative powers for their normal function. If you can’t breathe, you can’t think abstractly very well. If you heart doesn’t beat, your free will is quite impaired. If you can’t see, you can’t learn abstract ideas from books. If you can’t hear, you can’t learn abstract concepts by listening to someone. If you have a bad memory, you can’t learn abstract concepts very well because you can’t remember the perceptions and images necessary to evoke abstract thought…
So IQ depends on many things — on your vision and hearing, your imagination, memory and emotions, as well as on your intellect and will.Michael Egnor, “If IQ is inherited, is the intellect simply material?” at Mind Matters News
Takehome: The intellect and will depend on but are not created by bodily functions, senses, and memory. They are, however, affected by deficits in these areas.
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