Philosophy of Biology

What it asks

Philosophy of science was built largely on physics, and biology fits the resulting picture badly. There are few exceptionless laws. Explanations run through history and contingency. And biologists talk constantly about what an organ is FOR - a way of speaking that physics abandoned in the seventeenth century and that biology cannot do without.

So the field asks whether that talk is a shorthand that could be eliminated, or whether biology has recovered a legitimate notion of function that physics genuinely lacks.

The recurring problems

The species problem. More than twenty definitions are in use. Interbreeding fails for asexual organisms; morphology fails for cryptic species; lineage definitions leave the boundaries arbitrary. It is not clear that one concept can do the work of all of them, or that biology needs it to.

Units of selection. Selection is described as acting on genes, on organisms, on groups, sometimes on species. These are not equivalent, and which is the real level of selection has been argued for fifty years without resolution.

Function and teleology. A heart is for pumping blood. The standard analysis makes that a claim about selection history rather than purpose, which works well for hearts and awkwardly for traits that are currently useful and were selected for something else.

Adaptationism. Gould and Lewontin argued in 1979 that biologists too readily assume every trait is an adaptation, and tell plausible stories to fit. The criticism became a permanent part of the field's methodology and is itself contested.

How it developed

Biology was long treated as a junior science, either awaiting reduction to chemistry or as a collection of natural history. The modern synthesis in the mid-twentieth century unified genetics and evolution and made a philosophy of the science possible.

The field proper formed in the 1970s. The gene-centred view of evolution, popularised in 1976, made the units-of-selection question public and urgent. The spandrels paper in 1979 introduced a permanent methodological caution.

Etiological theories of function then gave the field its most successful piece of analysis: a trait's function is what it was selected for, which explains how a heart can be for pumping while also making a noise it was not selected for.

More recently the field has broadened well beyond evolution - into development, ecology, microbiology and the question of what an organism even is, which the discovery that every animal is a community of species has made much harder to answer.

The positions within it

Gene selectionism, organism selectionism and multi-level selection; adaptationism and its critics; etiological and causal-role theories of function; species as individuals and species as kinds. All are in the Schools section.

Where it stands now

The field is now among the largest in philosophy of science and has almost no interest in the reduction questions that once defined it.

The active work is on development and inheritance beyond genes, on the concept of the organism in the light of microbiomes and symbiosis, and on the use and misuse of biological categories in human contexts - where the philosophy of race and the philosophy of gender both meet questions this branch has spent decades on.