You are still using terms incorrectly. ’ Essence,’ in Aristotle and Aquinas, equivalent to the nature of the substance or being which exists. Scientifically man’s nature or essence is a rational animal. Philosophically, man’s essence or nature is a composit of body and soul. Man’s intellect is a property of man’s soul not his brain, which is the physical apparatus which the intellect uses.
So simpler means nothing if it is wrong.
Linus2nd