Introduction

We are all physicalists now. It was not always so. One hundred years ago most educated thinkers had no doubt that non-physical processes occurred within living bodies and intelligent minds. Nor was this an anti-scientific stance: the point would have been happily agreed by most practicing scientists of the time. Yet nowadays anybody who says that minds and bodies involve non-physical processes is regarded as a crank. This is a profound intellectual shift. In this chapter I want to explore its methodological implications for the human sciences. I do not think that these have been adequately appreciated.

It is sometimes suggested that the modern enthusiasm for physicalism is some kind of intellectual fad, fanned by the great successes of physical science during the twentieth century. But this underestimates the underpinnings of contemporary physicalism. The reason that scientists one hundred years ago were happy to countenance non-physical processes is that nothing in the basic principles of mechanics ruled them out. Mechanics tells us how material bodies respond to forces, but says little about what forces exist. Prior to the twentieth century, orthodox scientists countenanced a far wider range of independent forces than are admitted today: these included not only separate chemical, cohesive, and frictional forces, but also special vital and nervous forces. Consider the term “nervous energy.” This was originally a nineteenth-century term for the potential energy of the nervous force field.