"Yeah, it's not... we don't work from the assumption that there was a personal will behind what happened, at home. Our working theory, which I think is pretty sound, is that the animals that are better at having offspring who survive into adulthood are the ones who pass on their heritable traits. So if an animal happens to be a little faster or better at eating certain kinds of plants or something, they're more likely to survive long enough to have kids who have those advantages."

She shrugs. "Science is a method. It should work here as well as anywhere. We're just working with a different framework."