Puzzle

This week's Weekend Blip-Challenge theme is "PHILOSOPHY".
When that came out of the random blip-hat, I have to admit I groaned a bit, but then I had an idea.

So here it is.
It's a "Say What You See" style puzzle depicting five famous philosophers.
Can you get them all?

This is my entry for the Weekend Blip-Challenge.

PS. If you like puzzles, why not try bimbogami, a free puzzle site close to my heart. :)