I’ve recently written about philosophy of physics, because of a fascinating workshop I attended in Munich about the status of string theory and, more generally, the idea of non-empirical confirmation of scientific theories. (You can find my coverage here, here and here.) But of course I’m a philosopher of biology, and have mostly written professionally about evolutionary biology. Still, there is a way to connect the two, and it has to do with an analysis of the differences, if any, between physics and biology as examples of natural sciences. That happens to be the topic of an essay I wrote for The Philosophers’ Magazine Online, taking the inspiration from a well written paper by Marco Buzzoni, entitled Causality, Teleology, and Thought Experiments in Biology.
Buzzoni begins by quoting the venerable evolutionary biologist Ernst Mayr, one of the architects of the so-called “Modern Synthesis,” biology’s equivalent of the Standard Model in physics: “[the battle over the status of biology] has been waged between two distinct camps. One claims that biology does not differ in principles and methods from the physical sciences, and that further research, particularly in molecular biology, will in time lead to a reduction of all of biology to physics. […] The other camp claims that biology fully merits status as an autonomous science because it differs fundamentally in its subject matter, conceptual framework, and methodology from the physical sciences.”
There is no question in Mayr’s, Buzzoni’s and my own mind that the first option is simply not viable. Yes, of course biological organisms are made of molecules, which are made of atoms, which are made of subatomic particles, the behavior of which can be explained in physical terms. But it is equally obvious to any biologist that if you simply describe the physical-chemical behavior of living organisms and their parts without also asking why they are the way they are, you are missing the entire point of doing biology.
The way Buzzoni goes at it is by recasting biological hypotheses as thought experiments. In general, he follows Kant when he said that an experiment can be treated as a “question put to nature.” Obviously, experiments are teleological actions, they have a purpose (that of the scientist). And the fact that we can do experiments in physics and chemistry clearly shows that “teleology and efficient-mechanical causality are not only compatible but that final causes are actually the condition of the epistemic possibility of mechanical ones, since without our knowledge of final causes there would be no experiment and therefore no imputation of mechanical causes.”
The problem, as Buzzoni himself recognizes toward the end of his paper, is that we are still left with the unanswered question: why is it, exactly, that a teleological heuristic works so well for certain kinds of objects of study, but is entirely irrelevant for others? He says: “One might still ask the further question whether this depends upon an ontological difference [between the objects of study of physics and biology]. Philosophically speaking, I do not think that any sufficient reason has yet been given for answering this question affirmatively, even though there are some moral reasons for doing so. But this is not the interesting point.”
Well, here I beg to differ. That is an interesting point, and very much so. And that’s the point I focus on at the end of my TPM article, invoking a distinction between teleonomy and teleology, which Buzzoni does not make. Teleonomy is the appearance of purposefulness that results from some type of natural process, chiefly (exclusively, really) natural selection. That’s where the difference between physics and biology resides, as Darwin explained: physical systems are not teleonomic, while biological ones are. And then there are conscious agents like us, who are not just teleonomic, but capable of teleology: when we make an object, a machine, we do it with a purpose in mind, not just the appearance of a purpose. And that is what further separates biology from the social sciences (psychology, sociology, economics): in the latter one cannot make sense of things without invoking purpose.