Friday, April 25, 2008

The Individuality of Bacteria

One of the most common misconceptions about the biological study of life is that it promotes a determinism that denies individuality and freedom. That's one of the primary reasons why conservatives fear any biological account of human life. They also fear that the genetic determinism of modern biology prepares the way for a genetic engineering of life that will bring a dehumanizing tyranny leading to what C. S. Lewis called "the abolition of man."

Against this misconception, I have argued in a recent post that biological science shows the natural ground for the "Individuality, Contingency, and Historicity of Life." For example, I pointed to the individuality of bacteria: even when bacteria are genetically identical, their behavior differs in ways that show the uniqueness of each bacterium.

Now, in a recent article in the New York Times, Carl Zimmer summarizes some of the recent research confirming this point. E. coli is a species of bacteria that lives in our gut, and it is one of the model organisms for biological research, particularly in genetics. He writes: "A colony of genetically identical E. coli is, in fact, a mob of individuals. Under identical conditions, they will behave in different ways. They have fingerprints of their own."

In a sense, E. coli has "personality"--distinct traits for each individual that cannot be explained by genetics alone. The reason for this is that unlike simple machines, living organisms show an "unpredictable noisiness" in their biological operations so that genetically identical individuals act differently in ways that are not controlled by their genes. Such unpredictable differences are advantageous for evolution, because it allows some individuals to survive in harsh environments when many others die.

If the social sciences and the humanities are to be linked to the natural sciences, that link will come through the life sciences rather than the physical sciences, because the life sciences confront the same individuality, contingency, and historicity that characterize social behavior and human life.

1 comment:

K.S.Erickson said...

I take you to mean that human life is biologically determined and that this does not in a way threaten individuality, contingency and the historicity of life. This is because of the "unpredictable noisiness" of biological operations that allow for different behavior even in genetically identical organisms. Which is to say that biological (read: genetic) determinism is no determinism at all.

That would be true, if we were purely biologically (genetically) determined. But I would argue that we are instead situationally determined. This determinism also does not threaten individuality, contingency and historicity, but only because of the exact irreproducibility (to the atom) of a given situation, not because of some mysteriously inscrutable ghost in the machine. Situational determinism might eventually threaten freedom. Or it will at least force us to radically reconsider what it might mean for our actions to be free.

You say that "unpredictable noisiness" persists in biological operations, even in genetically identical organisms operating under identical conditions. But how can we guarantee the situations are identical? After all, the bacteria mentioned in the NYT article were next to each other. Sure, they were in roughly the same space under roughly the same conditions, but how much of that "unpredictable noisiness" is actually attributable to infinitesimal (molecular, even atomic) differences in the situation?

Just as a thought experiment, imagine that we one day develop the computing power to account for even the smallest differences in a lab setting. We have a computer that can measure the effect that the slightest dip in any number of factors would have on the transciption process within a cell. What is to prevent such a computer from predicting all the outputs if it can process all the inputs? There's no more unpredictability and therefore no more noisiness.

Even if such a computer could never be constructed, even if there will always be practical limits to our ability to calculate, doesn't the fact that this could happen in principle have implications for how we conceive of free action today?