Sometimes novels are really philosophy tracts in disguise. If you’re Neal Stephenson, this usually turns into an unwieldy doorstopper that uses its tremendous bullk to beat the reader into submission. If you’re Herman Hesse, you write a kind of novella that is also pretty dense yet somehow manages to be simple and light at the same time. Siddhartha is one of those delightful early twentieth-century novels that by modern standards do not work at all…