Rene Descartes believed that only humans have souls. Thus, only humans are capable of thought: animals are entirely mechanical. When you think that your dog is thinking, then, you are actually just confused by the marvelous intricacy of the machinery. I used to think that this was a rather straight-forward idea. There would be times when I thought it idiotic and times when I thought it represented a fairly subtle sort of mistake: but in either mood I thought it easily enough grasped. It was, as Descartes himself said of ideas he approved, "clear and distinct." But recently I encountered an article by John Cottingham that persuades me that getting right what Descartes has to say about animals is a bit complicated. There are ambiguities here. I should confess here that the Cottingham article is no very new contribution to scholarship. It was published in 1978, and has evaded my attention until this week. Still ... here we are. In Part V of RD's DISCOURSE he ex...