Monday, November 8, 2010

What are living bodies made of?

It seems natural, in thinking about the living body, to ask what living bodies are made of. And the answer might seem obvious: living bodies are made of organs and tissues, which are composed of living cells; these cells are built out of of proteins and other organic molecules, which are in turn made of elements like carbon, hydrogen, and oxygen. But this isn't the answer I'm going to offer here. Instead, I want to suggest that living bodies are not made of anything at all.

To understand what I mean, we have to turn our attention back on the question itself. What does it mean to ask what something is made of? What does this question assume about the thing in question, and what sort of answer are we looking for?

A roll-top desk not unlike my own.

Consider a simple example: an old roll-top desk that I’ve had since I was a child.

What is this desk made of? If we could pose this question to the artisan who made it, she'd probably tell us she'd built the desk out of wood and some metal fasteners. In other words, she would tell us about the materials from which it was constructed.

When we ask what an artificial thing is made of, this is the kind of answer we expect. We'd be pretty surprised if she replied that the desk was made from dead plant cells, or from atomic elements like carbon and iron. When we ask what a desk is made of, we want to know what materials we would need if we were going to build a desk ourselves. The artisan didn't assemble the desk out of elements or cells, but out of wood, nails and screws.

When we learn what these materials were, our question is answered. It would be strange if, having learned that the desk was made of oak, we continued pestering the craftsperson to tell us what the oak was made of. She would probably reply that she hadn’t made the wood—it was cut from an oak tree. Similarly, the steel fasteners were forged out of iron ore, which wasn't made but rather mined from within the Earth.

My desk, like all manufactured things, is made of materials that were not themselves manufactured. Human manufacturing depends on “raw” materials like wood and ore, which are natural formations rather than artificial products. When we ask what an artificial thing is made of, we are ultimately asking after these “raw” materials, from which every manufacturing process begins.

But what about these materials themselves—what are they made of? Here again we need to consider just what we're asking when we pose this question, and what sort of answer we're looking for. When we asked what the desk was made of, we were asking about the materials that its maker used in constructing it. The desk was made from the wood of the oak tree. But it makes no sense to ask what materials the oak tree’s maker used in constructing it, since we know that the oak tree had no maker. No one made the oak tree out of anything, because the oak tree wasn't made at all. A tree can be cultivated, but it can't be constructed or manufactured. Like all living bodies, the tree is not built, but grown.

This leads us to a very important question: what is the difference between these two ways of coming to be, manufacturing and growth? But I'll have to save this question for another post.