Peter King has written a top-shelf article on Thomas Aquinas’s view of emotions. This is my summary of some of his key findings.
Thomas Aquinas believed that emotion is “a semi-autonomous faculty of the soul”. An emotion is something the soul experiences, not something the soul does.
Emotions are reactions you experience when you perceive something. This apprehension of a thing can happen either mentally or physically. A person, for example, can feel joy either by imagining chocolate or by tasting chocolate.
Emotions are reactions, but they can also cause things too. Fear can motivate you to run. It can also make your teeth chatter.
Although an emotion is a reaction, that is, something causes it, Aquinas thinks we have some control over the emotions we experience. Emotion “is not completely in our power since it precedes the judgment of reason," but “it is in our power to some extent.” King suggests that in this way, emotion is like sight. You can only see what you see, but you can also direct your eyes to look at something. This means that the experience of an emotion or the power of an emotion can be somewhat what controlled (i.e. willed).
One way we control our emotions is through thinking and reasoning. This is because how we interpret things can affect how we feel. Imagine you see a large dog and become afraid. You are afraid because you interpret his size as a danger to you. But if you discover that the dog is a therapy dog used in hospitals to calm children, your fear may change into a desire to pet him. The dog has not changed, only your understanding of the dog. And because your understanging has changed, your feelings have followed. If it only it were always this easy!
Sometimes, we talk about emotion in terms of movement. “I feel love toward my wife,” for example. Borrowing from physics, Aquinas thinks about all emotions as types of movement directed towards good or evil.
Aquinas identifies eleven main emotions. The emotions directed toward what we perceive as good are love, desire, hope, despair, and joy. Emotions directed toward what we perceive as evil are hate, aversion, confidence, fear, sorrow, and anger.
Notice the pairs, except for anger, which is unique. Read King’s article to understand why.