‘In moral philosophy it is useful, I believe, to think about plants.’ The words were spoken to an audience of American philosophers in 1989. The speaker was trying to provoke a reaction, but this might have gone unnoticed. After all, Philippa Foot – nearly 70 by then – didn’t look like a heretic.
There is a clue in her reference to moral philosophy. For at least the past 200 years, people who have thought about these things have suspected – or hoped – that morality is the one thing that sets human beings apart from nature (or should one say, the rest of nature?). Nature is the realm of laws, stern and unbreakable, and morality that of freedom. Nature is how things are, morality how they ought to be. If there’s anything to these points of contrast, then what seems at first a mere platitude sounds more like an absurdity. We are not, in the relevant sense, part of nature – not even of that part of nature that consists in our fellow animals, and, still less, plants.
Have we anything to learn about morality from plants? This might well depend on that bigger question: are we, or aren’t we, part of nature? One of the many things that set Foot and her allies in philosophy apart from others of their generation was their refusal to make an either/or of it.