For the John Templeton Foundation, I interviewed physicist and biologist Alan Love.
How do people usually think and talk about purpose in the context of biology?
Biologists often use language that imputes agency or goals to living systems and have done this since the time of Aristotle. However, in the last two hundred years, many have argued that this is at best “as- if” or heuristic talk, and at worst an error. As a result, the phrase “science of purpose” sounds odd to many biologists, who would rather say that purposiveness is just apparent and can be fully accounted for by processes like natural selection. To give a simple example, we might say that teeth are “for” chewing. This seems straightforward enough, but the concern is that in an evolutionary process, there is no anticipation of the need to chew. So how do you get a trait with a purpose without that kind of foresight? A lot of biologists feel that the language of purpose steers us away from understanding evolutionary processes and is therefore illicit, but that other ways of talking — for example, in terms of “function” — are okay.