psych notes
res extensa is physical matter
res cogitans is the mind
Rene Descartes thought the body and mind were 2 different things which brought the thought of dual natures, which is called cartesian dualism
because of the natural laws that we have it allows us to scientifically study the mind
most philosophers thought that the body is mechanical and the fact that the brain is mechanically put together
front part of the brain in the pic he showed it was  the part that could understand speech but couldnt produce sentences or barely any speech at all
the other part  of that brain was the total opposite of the front which was  couldnt understand speech but could produce it
Paul asked people that had the issue of producing speech"after your dead can i open your skull and examine your brain" some of the people said yes in their own shape or form
Frankenstein was around the  same time in the 1800s which was visually showing the belief that we were thinking the body was mechanical.
Another philosophical person named Luigi Galvani did experiments on frog legs,To show that it once did have a soul in there but now at that current time it doesn't.
He showed this by using electricity. if you put a jolt of electricity in the muscle of that frog leg then it will move.
going on what Descartes thought earlier it was more like our soul controlling us like puppeteer with his puppets. it can step in and do certain actions for us or it can lay back and let us do our own things
most philosophers that considered Descartes idea went radical with it. John Locke in the late 1600s started to push the idea of the mind being physical and mechanical that it was  subjected to the thought of natural laws which means we could study it scientifically.
James Mill put a name to this idea which is Materialism. Material beings in a Material world which brings up the theory if we don't have a soul then human behaviour is based off of natural laws that we could potentially study. This carved a way for us to be able to psychologically investigate ourselves.