Scully on the Radio

Longtime reader Khursh Mian Acevedo sent a link to a radio interview with animal-rights advocate Matthew Scully, who happens (like me) to be a conservative. See here. Thinking that animals matter, morally, is not a liberal cause. How it came to be seen as a liberal cause puzzles me. Was the abolition of slavery a liberal cause? Must one be a liberal to think that making sentient beings suffer for trivial reasons is wrong? And by the way, not all liberals have been proponents of animal rights. Immanuel Kant (1724-1804), one of history's great liberals, was decidedly not a proponent of animal rights. Indeed, he thought animals had the moral status of inanimate objects.