Three awkward cases
A stone is not alive and a dog is. There is no difficulty there. But the three cases below are not so easy — decide what your own answer is for each before reading on.
1. A hen's egg
It does not move. It eats nothing. It does not grow. Yet keep it safe for a few weeks and a chick comes out of it.
2. A piece of tissue in a freezer
Tissue taken from the body of an organism can be kept in a freezer for a long time. It does nothing at all while it is there — but graft it suitably into another organism and its living characteristics appear again.
3. A fossil thousands of years old
It is a rock. Yet there is still DNA inside that rock, and genetic engineering has found a way of grafting those DNA molecules to produce new organisms carrying the characteristics of the old ones.
What the three have in common
Not one of them shows a living characteristic at the moment you are looking at it. Yet all three keep the capacity to become an organism — the egg needs warmth, the tissue needs a host, the fossil needs a laboratory. So the question "what is it doing right now?" is not enough on its own.
This is not a question without an answer
In the end, living or not living is settled against a definite list of characteristics rather than against a feeling. There are eight of them, and they are what this chapter is about.