Plants and Moral Philosophy

I like this part of Philippa Foot's Philosophy Now interview:

An admired colleague of mine, Michael Thompson, has said of my work that I believe that vice is a form of natural defect. That’s exactly what I believe, and I want to say that we describe defects in human beings in the same way as we do defects in plants and animals. I once began a lecture by saying that in moral philosophy it’s very important to begin by talking about plants....

So let’s take plants. A plant needs strong roots, and in the same sort of way human beings need courage. When one is talking about what a human being should do, one says things like, “look, he should be able to face up to danger in certain circumstances, for his own sake and for the sake of others.” But this is like saying, “an owl should be able to see in the dark, should be able to fly” or “a gull should be able to recognize the sound of its chick among all the cacophony of the cliff.” And if you think of it in this way then you’re not going to think that there’s a gap between facts and evaluation – between description of facts, such as ‘owls hunt by night’, that’s a description of fact, and another description, such as ‘that owl’s got weak eyesight; it’s doesn’t seem to be able to manage in the dark’. These are the central notions. And that’s why I thought we should start moral philosophy by talking about plants.