You: That is a strong argument, but before you can convince me of it you will have to explain exactly what you mean when you use the word "life?"

Aaron: Surely that is a trivial question. You and I both know exactly what life is. You are avoiding the question.

You: Not at all. If you cannot define life then you cannot tell what things are living and what things are not. A column of smoke or a stream of water, for example, might seem to be alive if we judge by the apparent intelligence of its movements. And if by life you mean a "life force" or some such metaphysical concept, then I will have to...

Aaron: Yes, yes, yes. I see where you're going and I certainly won't let you trap me so easily. I would say that living creatures are those which move, grow and reproduce, and that life is whatever force allows them to do these things.

How do you respond?

  1. Not all living things can move. Go
  2. Not all living things grow. Go
  3. Not all living things reproduce. Go
  4. Some things move, grow and reproduce but are not alive. Go