Today we began with a question about what a human being is and ran into a problem in the way that medieval philosophers understood understanding itself.
First, we looked at Augustine. He wasn’t influenced by Aristotle, but rather by Plato. On his view, you are your soul, but not your body. Your soul is joined to (perhaps one might say, trapped in) a body, but the body is not you. When you die, your body will fall apart, but you will be unharmed.
Next we looked at philosophers influenced by Aristotle: Averroes, Siger of Brabant, Aquinas and Buridan. All four adopt the Aristotelian view that all substances are hylomorphic compounds, meaning that all real things are unions of form and matter. This means that your soul is a form, but unlike Platonists, Averroes, Siger, Aquinas and Buridan do not think you are separate from your body: you are the combination of matter and form. Now this makes it hard to see how you could survive after death, as both Islam and Christianity teach. These philosophers found themselves in a good news/bad news scenario. Good news: Aristotle did seem to think there was a part of the soul that survives death. Bad news: it’s not obvious that such a survival means individual survival.
What Aristotle wrote was that the part of our soul that understands, the intellect, can be understood (like anything) in terms of form and matter. The ‘matter’ has lots of names: the potential/patient/hylic intellect. That’s the part that adopts the structures that you understand, and permits you to remember. Then you have the active/agent intellect. This allows you to select what to remember. And Aristotle then says that the agent intellect (1) to some extent rises above matter, because it has no corresponding material portion, and (2) is eternal. It’s important to understand that Aristotle is being really unclear here. There was no consensus on what he was saying in the middle ages, and there isn’t any today.
Averroes and Siger take Aristotle to be saying that the agent intellect is like an additional, active form that is shared by every human being. When you’re alive, you feel as though you’re an individual, thinking and remembering. But when you die, you don’t just lose your memories (because you lose your hylic intellect, which dies with your body), but you also lose your individuality. In most cases, Aristotelians say, a hylomorphic compound does the thinking. But in the case of the agent intellect, Aristotle seems to say that a form does the thinking. If that’s true, the form presumably continues to think after we die. But since we’re unions of form and matter, that thinking can no longer be our thinking. In consequence, there is apparently no individual survival after death.
Aquinas’ strategy is to take a more moderate reading of Aristotle. Maybe all Aristotle meant, Aquinas says, is that the intellect is the most pure, un-material part of you, and the agent intellect is the most pure, un-material part of the intellect. For that reason, perhaps it survives. But it’s definitely a part of your form, and it is your agent intellect, Aquinas maintains. Otherwise it couldn’t be you that survives death. Aquinas is interpreting Aristotle here, but he does something else interesting too. He argues that if a human being isn’t demarcated by its form - if there’s this separate agent intellect form thing that does our thinking - then Aristotle’s picture of science wouldn’t work, because we couldn’t identify a species that really explains what human beings are. So Aristotle has some reason to agree with Aquinas’ interpretation, because otherwise his science might not work.
Ben raised the interesting question of whether maybe Aristotle changed his mind. That’s always a question for an interpreter, and for a historian of philosophy, but it should be a last resort. Otherwise we risk not seeing the clever ways in which philosophers solved problems. In a way, that’s because historians of philosophy are more interested in the philosophy than the history. If it turns out that Aristotle was inconsistent, then all we’re left with is history. So we proceed on the assumption that he was consistent, in the hopes of finding a brilliant resolution to the problem.