Every New Year the Edge poses a question and publishes the responses from among the world's intelligentsia. It's fun to read the responses but, even more fun to write your own.
This year's question is What have you changed your mind about? Why? With the rather important sub-text science is based on evidence. What happens when the data change? How have scientific arguments or findings changed your mind?
The sub-text makes all the difference. Without that we can all think of things we've changed our minds about. But how often are we faced with major paradigm shifts from one set of views to a completely different set, based on scientific evidence, and quite possibly in the face of our own prior beliefs or prejudices. Rarely, I'll bet. Most scientists tend to be educated within a particular tradition and then remain within its established dogma throughout their working lives.
Without doubt the most profound scientific change of mind I have experienced (which took many years) is in relation to Newton's first law of motion, which I now believe to be wrong. However, I discussed this two years ago, in response to the Edge 2006 New Year question, so I won't repeat it here.
So, what else have I changed my mind about?
Well, in November 2007 I was lucky enough to be invited to a University of Bristol workshop on Mathematical Models of Cognitive Behaviour. The assembled speakers covered a broad spectrum of topics, but one in particular really caught my imagination. Dennis Bray's brilliant and illuminating talk introduced the computational processes going on inside the single cell, e-coli. I learned, to my astonishment, that single-celled micro-organisms have a complex repertoire of behaviours including memory and adaptation (in addition to finding food and reproduction). Behaviours that one normally associates with far more complex multi-celled organisms with nervous systems.Yet these are creatures with no nervous system. But, as I learned, an exquisitely complex set of molecular computational processes are present within the dense chemical soup (cytoplasm) encapsulated within the cell. Dennis explained that for e-coli, for instance, we now have a kind of circuit diagram of the complete set of computational processes. But it's far from simple!
Before Dennis' talk I was fond of saying that the robots in our lab are simpler than the simplest animals. As a result of what I learned from his talk, I've now seriously downgraded my assessment:
Our robots are simpler than the simplest single-celled micro-organisms.