Thursday, September 29, 2005

The New Sciences of Complexity

Let me suggest that the new sciences of complexity are as reductionist as older sciences.

New or old, each science still abstracts one facet of reality that we can understand, though we can now use more complex models that describe more complex facets of reality.

For example, the old science of Newtonian physics was able to understand the motion of one or a few lumps of matter at ordinary scales and speeds because this is a relatively simple aspect of the world. Physicists could analyze this facet of reality back in the days when they did calculations by hand, and that is why they abstracted this facet of reality as the subject of a science.

The new science of modeling global climate tries to understand a much more complex system. Today, we can abstract this facet of reality and deal with it because we have computers that use complex algorithms to generate the model and do the calculations. However, the model is still an abstraction and simplification of reality.

This point about science has an important practical implication: that we should not fall into the modernist error of thinking that science gives us the sort of complete understanding that would let us manage the world completely.

Thus, we should not expect that climate science will let us develop technologies to manage the world's climate - for example, by creating huge algae farms in the oceans that absorb carbon dioxide. This could reduce global warming, but who knows what it would do to the ecology of the oceans, which are studied by a different science using a different model?

Instead, climate science should show us that we are creating a danger and that we should rein ourselves in and not intervene in the world's environment so dramatically.

The antidote to the modernist error is not more complex computer models. It is a sense of modesty.