Have you taken philosophy or studied it independently?

Both, actually. For a really good intro to philosophy, I would suggest A couple of Mortimer Adler's books. "Aristotle for Everyone," "Six Great Ideas," and "Ten Philosophical Mistakes." After that, there is a series of books available at Borders, etc., called VLIs. It stands for Very Little Introduction. They give a pretty good introduction to a wide variety of subjects. After all of that, you should be pretty well prepped for any source text you want to read,