David Wolf in The Browser:
Sartre was also a novelist, and his novels are often described as philosophical. Do you think novels and novelists can really engage in philosophy, or is that only possible if you're a professional academic philosopher?
I think professional philosophers often like to make their subject smaller than it really is by setting arbitrary limits. As far as I'm concerned, philosophy is any human enterprise that involves critical thought about basic questions, like how we should live, what is the nature of reality and so on. Those questions can be asked seriously in all kinds of forms. So I don't see the subject as restricted to nerdy philosophical papers in refereed journals. Some of the most important contributions have been literary. If you think of classical philosophy, you have Plato's very literary dialogues, and Lucretius's On TheNature of Things is a poem! Some parts of TS Eliot's poems are very philosophical. Kierkegaard is a poetic writer who uses fictions, and Nietzsche uses aphorisms and poetry. They're all philosophers.
More here.
