Man is a rational animal. What does this mean?
An animal is sentient living substance, but the idea of sensation is most central. So a human being is defined by this strange operation of “rational sensation”. What is rational or intellectual sensation? Mere animals simply have sentient sensations, and angels have intellectual intellections. Man is defined by a much stranger activity of intellective sensation.
Sensation is not merely the five exterior senses, but the interior senses as well, and that whole vast network of powers that come along with sensations. Sensations don’t just involve knowing objects but also desiring them, remembering them, being attracted by them, etc. All of this vast tangle of acts and organs and chemicals and urges is somehow “intellectual” in man, and it can only find its perfection by being “rational”- whatever this means. We don’t know all the details of how one perfects this operation of “intellectual sensation” we only know that perfecting a human being involves doing so. We only have vague and generic ideas of what sort of activity would perfect hogs or roses, but we know exactly the sort of activity that perfects a man: perfect rational sensation.
The first thing to draw attention to is that man is perfect by an activity or operation- since rational sensation is a kind of activity. Other things will certainly come into play, but operation is at the root and basis of all of them.
The kind of operation must be a harmony of sense and mind. Sensations that are contrary to mind can never be perfective operations, no matter how much evidence sense might marshall to the contrary. If we determined that some sense pleasure, for example, were really contrary to the desires of intellect, then we cannot call it pleasant to a man. It might be pleasant or perfective of dogs or some other animal, but not to us.
Is all of this too intellectual? By intellectual we no doubt mean cut off from the deep passions and longings. But man cannot be intellectual in this way. Man’s definition requires reason to be integrated into passion and longing. A passion hostile to reason is not human, and neither is a reason hostile to passion. Right reason will certainly have to deny disordered and erroneous passion, but for the same reason rightly ordered passions must reject and supress disordered and erroneous reason.