There are numerous complex issues here in the philosophy of so-called animal cognition or comparative ethology, but it seems to me that the burden of proof is with anyone who says no. The same issue arises, clearly, for human beings. So if we say that we do not know that the beagle feels love when he wags his tail and bays a bit and licks us and even gives us little nips behind the ears, and is obviously happy - more than happy - to see us, and delights in our presence, why would we not say the same about the human being doing these things, or their non-beagle equivalents? It's no good saying that he's doing it because we feed him. The same is true in the human case, but the manner of feeding is different, as is what is fed. It is difficult to imagine an ant loving us, but I think that is because there is no demonstration of affection from ants, no licking or running round in circles and so on. They would be ignoring us, if they were human and doing what they do. None of this is an assumption, though; it...

Once the premise is accepted that the treatment of animals that is required to make fur or leather goods is cruel, it does seem to follow that we should do everything we reasonably can to stop it, or failing that, we should not support it. I suspect that you are right to call your friend's view "extreme". For one thing, manufacturing fake fur and leather and vegetarian or vegan food that tastes a bit like meat, though it isn't, may actually help the campaign against the cruel treatment of our suffering evolutionary cousins. On the other hand, even if one was attracted to the idea, there is something very wrong with manufacturing handbags to look like human skin, or fake human meat for morally scrupulous cannibals. Why the double standard?