Epiphenomenalism – the Do’s and the Don’ts

When philosophers defend epiphenomenalist doctrines, they often do so by way of a priori arguments. Here we suggest an empirical approach that is modeled on August Weismann’s experimental arguments against the inheritance of acquired characters. This conception of how epiphenomenalism ought to be developed helps clarify some mistakes in two recent epiphenomenalist positions – Jaegwon Kim’s (1993) arguments against mental causation, and the arguments developed by Walsh (2000), Walsh, Lewens, and Ariew (2002), and Matthen and Ariew (2002) that natural selection and drift are not causes of evolution. A manipulationist account of causation (Woodward 2003) leads naturally to an account of how macroand micro-causation are related and to an understanding of how epiphenomenalism at different levels of organization should be understood. 1. The Weismann Model August Weismann (1889) is widely credited with disproving the Lamarckian theory of the inheritance of acquired characteristics. In one of his famous experiments, Weismann cut off the tails of newborn mice; when the mice grew up and reproduced, their offspring had tails as long as their parents’ had prior to surgery. These results remained constant over many generations. Weismann saw the same pattern, and the same evidence against the inheritance of acquired characteristics, in the fact that circumcision over many centuries had not caused boys to be born without foreskins. He also thought that his theory of the continuity of the germ plasm threw further doubt on the inheritance of acquired characteristics, though it is worth asking whether this theory was evidence against Lamarckianism (as Gould 2002 argues) or merely assumed that Lamarckian inheritance does not occur. Our interest here is in the logic of Weismann’s experiments. Regardless of their general significance for “Lamarckianism,” they clearly provided evidence that acquired tailessness in mice parents failed to cause tailessness in mice offspring. How did the experiments manage to perform that function? 1 Lamarckians argued that Weismann’s result concerning mutilations has no bearing on characteristics that are useful to the organism.