No. You aren't a freak. People do different things when they are stoned. I know some people who do nothing but play video games or watch cartoons. I like to read when I'm high as well. When you are high your imagination really soars. So I can see why you like reading about philosophy. Philosophy is just ideas and usually it's very hard to understand. Being stoned helps you to understand it better. So no you aren't a freak.