Aw, C'mon.
You already believe in a least two classes: Evil collectivists and freedom-loving libertarians. Maybe three, I forgot the useful idiots.
Classes are like Bragg Planes in a crystal. They arise independently from geometric lattices and they are arbitrarily defined simply by your perspective of perfectly regular crystalline structures, but they still diffract xrays so you can deduce from their shadows the internal arrangement of the atoms within. They are very real and extremely useful as a tool to probe complex hidden structures.