Descartes, Dualism, and Bodies

In modern philosophy, Descartes gave us the idea that there was a fundamental split between two kinds of things - mental things and physical things. Before that, people did not make quite the same kind of hard distinction, even when talking about souls.

For Descartes, the fundamental characteristic of mental substance was that it could think. Thinking meant being able to judge, reflect, distinguish, etc. It also meant self-reflection.

The body's fundamental characteristic was that it had extension, which meant that it "took up space".

So, the mind was not spatial. And, the mind was where our fundamental nature lay. That meant that our relationship to space in the world was non-existent. It also meant that our knowledge, the contents of our mind, had nothing to do with space, or for that matter, place.

And what was the body? Was it an organism? Yes, but what's an organism? Just a machine, spatially related and integrated parts that work together. Our bodies are like clocks.

So, Descartes' idea of what we are: we are the
ghost in the machine.