One of the more common debates in ethics is about the order between the intellect and the will, and its not uncommon for people to divide systems of ethics into the rational and the volitional/sentimental etc. St. Thomas is generally taken to be one of the high priests of rational ethics- although there is a good deal of competition here. Many who read St. Thomas’s ethics get the impression that acting well is just a certain way of thinking well.
Much could be said against this caricature of ethics (anyone who thinks that being good is just a matter of thinking hard enough or being logical enough hasn’t thought much about being good) in order to get a grasp of where St. Thomas falls in this scheme, it’s best to start with the very first thing he says about ethics. As a set up, think normally and fill in the blank as you think St. Thomas would:
“What is distinctive and unique about man is ______, which sets him apart from the beasts”
Until last week, I would have put “reason” in the blank, and I think most thomists would also. Then, of course, another group would put “the ability to love” in the blank, and off we’d go… That’s why I was startled to read, in the very first sentence that St. Thomas writes about man in the moral section of the Summa:
The actions which a man does, the ones that alone are properly called human, are those which are proper to him so far as he is a man. But man differs from the irrational creatures in this that he is the lord of his own acts. So those actions are properly called human of which man is the lord. But man is lord of his acts through reason and will…
actionum quae ab homine aguntur, illae solae proprie dicuntur humanae, quae sunt propriae hominis inquantum est homo. Differt autem homo ab aliis irrationalibus creaturis in hoc, quod est suorum actuum dominus. Unde illae solae actiones vocantur proprie humanae, quarum homo est dominus. Est autem homo dominus suorum actuum per rationem et voluntatem…
The basis of St. Thomas’s ethics is man as lord. Reason and will are mentioned together as tools that allow for this lordship. To leap to “reason” would be to leap over the very first thing St. Thomas says about ethics.