Why aren't we done with philosophy? After thousands of years and a parade of togas, cravats and very tight updos, haven't we pretty much covered humanity's questions? Maybe. But given the fuss a controversial mind like Peter Singer's can still raise, probably not. The author of Animal Liberation and The Way We Eat: Why Our Food Choices Matter, among other books, is visiting from his post at Princeton and giving a free lecture at the Van Duzer on Friday at 7 p.m.

• Meow, Peter Singer.

He's a utilitarian (Team Kant), but without the special treatment for being human. Animal Liberation set the animal rights movement afire by questioning why human needs should be put above other sentient beings. (Maybe don't wear that leather jacket to the talk.)

Some other controversial positions on ethics: Abortion? No. Surrogacy? Yes. Performance enhancing drugs? Sometimes. Euthanasia? No. Redistribution of wealth? Yes. Eating animals? No. Bestiality? Sometimes.

I'm sorry, what?

But it's the why that's the thing. He's not just trying to take away all your fun — or give it back, depending on what you're into — Singer is looking at the way we live and asking if we're doing good or harm and if there is a morally responsible way to live. Which may be why we're not done with philosophy. Because the more we get used to the way we live, the more we have to question it.