Let us dispel the longstanding idea that living systems must be regarded as machines. There never has been a machine made by humankind that works as cells do.

In particular, life should not be equated with that special kind of machine, the computer. It is certainly true that life performs kinds of computation, and indeed there are key features of biology that can be fairly well understood using the theory of information developed to describe modern information technologies.

What is more, a comparison with machines can sometimes be a useful way of thinking about how parts of the process that is life operates. It is meaningful to say that our cells possess pumps, motors, sensors, storage, and readout devices.

However, that is very different from the modern trend of discussing the fundamental features of living organisms by comparing them to electrical circuits, computers, or factories. No computer today works as cells do, and it is far from clear that they ever will (or that this would be a good way to make a computer anyway).

There is so far no technological artifact that provides a good analogy for living systems. These are a different kind of entity, with their own logic. Living entities are generators of meaning. They engage their environments (including their own bodies) to obtain things that have meaning for them: moisture, nutrients, warmth.

It is not sentimental but simply following the same logic to say that, for many if not all organisms, another of those meaningful things is love.

Philip Ball, How Life Works