Importance

The question also seems to come with a presupposition: that biology is in fact not physics, in any of the senses above. This background assumption reflects the dominant view of scholars in philosophy of biology today, although it’s definitely still open for debate. In fact, philosophers of biology have made it one of their basic concerns since the 1960s to demonstrate that biology is not the same as physics. The way I’ve posed the question therefore cuts deeply to the identity of philosophy of biology as a whole: that philosophical conclusions about physics don’t simply port over to biology. You need people studying both sciences (at least) to have a chance at answering philosophical questions about science more generally.

This answers why professional philosophers of science care that biology is or isn’t physics. It’s at the root of many different research topics they’re working on even today. But why should the rest of us care? It is admittedly a meta-level question, sitting on top of many more concrete debates and issues of broader public interest.

One answer is that it can illuminate why philosophy of biology is the way it is today. Why are some topics given lots of attention while others, seemingly of greater public or scientific interest, are basically unexplored? Philosophers of biology have spilled untold ink on debating the nature of biological species but have written almost nothing on the global crisis of biodiversity loss today. (That’s not to say there aren’t lots of people in other fields working on this, of course.) Moreover, why have philosophers of science prosecuted their debates in such idiosyncratic ways compared to the methods of either other fields in the humanities or the natural sciences? Thought experiments and introspective intuitions have played an outsized role in Anglo-American philosophy, but why these carry any weight as evidence about the nature of reality or scientific knowledge is probably obscure to most people.

Another answer is what it can teach us about how science works. Since its origins, philosophy of science has aimed to advance critical reflection on the conduct of good scientific research. There is great value, then, in understanding the fundamental reasons philosophers (and scientists) have uncovered to believe that good research is different in biology versus physics. Asking why biology isn’t physics therefore provides an opportunity to pull together and synthesize lessons from many different areas of philosophical research, helping us see the deeper principles and assumptions behind our conception of scientific practice.

Mapping Out the Question

One initially plausible answer to why biology isn't physics is that living things are more than the sum of their physical parts. The distinctive nature of living things then explains why we need a special discipline (i.e. apart from physics) devoted to studying them.