1) What is a mind? Is it the same as the brain or is it different?
2) If something cannot be touched or seen, does it really exist?
3) What are thoughts? As Fran says "so the thoughts in our minds are really just the traces of things in our memories?" Is this true?
4) Is it true that all the thoughts that are in our minds are caused by things that are outside of our minds? What kinds of things exist only in our minds?