One view of the mind says that connected to every living body--or perhaps only to living bodies that are able to think and be self-conscious--is a separate, non-physical thing we can call a soul. The body is one thing, a physical thing; and the soul is another, independent and non-physical thing. While the body is alive, the soul is connected to it, but it's possible for the soul to go on existing even after the body is destroyed.
The view of the mind is called dualism, because its proponents think that there are two kinds of things: physical things and mental things (souls). The souls are not made up of physical parts. In principle, they can exist independently of any bodies or other physical things. To think or have feelings requires you to have one of these souls.
So the dualist thinks there are two kinds of things. Other theorists think there is only one kind of thing.
?The materialist or physicalist says that the only things there are are all material or physical things. Materialism was originally the view that everything is made of matter. (That's why it's called "materialism.") Nowadays, though, philosophers have broadened the meaning of this term, so that you can still be a materialist even if you believe in gravitational fields, curves in space-time, and other things which are clearly not matter. Basically, the materialist believes in whatever our best physics tells us about.
?The idealist says that there are no material things, there are only minds and thoughts and experiences. There is no mind-independent, physical table here; there are only certain experiences I have as if there's a table.
You've probably all heard the following philosophical problem: Suppose a tree falls in the forest but there's no one there to hear i ...