Denis Walsh, University of Toronto - The Paradox of Population Thinking: First order causes and higher order effects
Darwin's discovery of natural selection was achieved by a change in perspective Ernst Mayr called ‘population thinking’. In its Modern Synthesis version, population thinking seems to embody paradox: that the processes that go on within organisms both are and aren’t explanatorily relevant to evolution. I attempt to diffuse the paradox by introducing a distinction between two kinds of explanations of population phenomena: first-order cause, and higher-order effect explanations. These are, I argue, complementary, autonomous, and both necessary modes of evolutionary explanation. In first-order cause explanations the properties of organisms are relevant; in higher-order effect explanations they are not. I attempt to resolve the recent dispute over the proximate/ultimate distinction in terms of the first-order cause/higher-order effect distinction.