p.s. A late-breaking comment yesterday made me laugh.
One of the most reviled views in the history of philosophy is Descartes’ view that animals are mere machines. The relevant texts are a trifle ambiguous, but he does seem to say that animals have no conscious life whatsoever. Your cat jumps off the couch and approaches his food because of signals in his brain, but without visual images or sensations of hunger. If it would give you pleasure to kick the cat, there’s no reason to hold back, so far as any feelings of pain are concerned.