We’re moving into Aquinas on human nature now. There’s some really interesting stuff in here – really strong traditions that move throughout much of Western philosophy, especially concerning the human soul and its relationship to the body. We’ll start with 1a.75.1, on whether the soul is corporeal. We’re not going to be able to answer the questions raised here for a while, but we’ll start by laying the groundwork.
Aquinas starts off by setting up a bunch of reasons why the soul might be corporeal. For instance, he points out that souls cause changes in human bodies. Souls animate bodies – if you’re dead, right, and your soul has left your body, then your body isn’t moving any more. It needs a soul to move around. And if you think about it, “there has to be some contact between the cause of change and the thing changed.” If there’s no contact between two things, there can’t be any change. Think about it in terms of physics, say – Newton’s first law states that an object will remain at rest or in uniform motion unless acted on by an external force. That ‘acting on’ involves some degree of contact. If you throw a ball up, it only falls down because it’s within the gravitational field of Earth. Change in speed and direction is predicated on contact with Earth’s gravitational field. If you had an object that somehow wasn’t affected by gravitational fields, and you threw it up in the air, it would just keep going forever – because there’s no force acting on it to make it stop.
In the same way then, if souls can affect changes in physical bodies, there must be some contact between the two. And if physical bodies are physical things, which they kind of are by definition, then souls must also be physical, because otherwise they couldn’t come into contact with bodies. There’s actually a really fundamental question here, right – if souls are these spiritual things that survive after death, but bodies are physical, what’s the relationship between them? Do they just exist as two totally isolated halves of the individual? If not, how do they relate to each other? We talk about how certain immoral actions can damage or corrupt your soul – well, you and me don’t talk about that, but we can imagine people using that sort of language, right. But how do physical actions performed by a body affect the soul? What’s the interface between the spiritual and the physical?
Aquinas begins his response by taking a step back and going ‘yeah but what the fuck is a soul anyway?’ He suggests that a soul is “the root principle of life,” which – well, okay, let’s take another step back. There’s actually a second underlying question he’s asking too – what the fuck is life? What’s the root principle, the absolutely basic fundamental first thing that makes you alive and not just an inanimate object? We might say, well, you’ve got a heart, and it pumps blood round your body, and that makes you alive – but then Aquinas would say well, what makes the heart alive? I’m really not a biologist, but I imagine we’ll eventually end up at cells – even then, why the fuck are those alive? The solution, for Aquinas, is to say that the soul is the root principle of life. You are alive because you have a soul in you, and that soul animates your body and makes you alive. When you die, your soul leaves your body and your body becomes inanimate.
There’s not a lot else to say at the moment, so I’m basically going to leave it there. Aquinas doesn’t answer the question about the relationship between the body and the soul for a little while. We will revisit this issue next week, because it’s addressed more fully throughout 1a.76 – I just don’t have the space in this post to do it justice. There’s a few other interesting questions that I invite you to look at in your own time though – 1a.75.3 asks whether animals have souls like humans, and that’s pretty interesting. Also in 1a.75.4, Aquinas notes that “Augustine commends Varro for judging that ‘man is neither the soul alone, nor the body alone, but body and soul together.” Aquinas is busy arguing here that people aren’t just souls – we’re not just purely spiritual creatures running around in skin suits, right. Our physical bodies are important to our actual essence: “it belongs to the very conception of ‘man’ that he have soul, flesh, and bone.” You wouldn’t call a hand a person, so you can’t call a soul a person. It’s mistaking the part for the whole. Next week, 1a.76, where we’ll resolve this question of the relationship between the body and the soul.