Causal Closure Thesis

Thus many contemporary thinkers adopt a physicalist view of the mental realm because they think that otherwise we will be unable to explain how mental processes can causally influence our bodies and other physical items.Similar considerations motivate ontologically naturalist views of the biological realm, the social realm, and so on.The great majority of contemporary philosophers would happily accept naturalism as just characterized—that is, they would both reject “supernatural” entities, and allow that science is a possible route (if not necessarily the only one) to important truths about the “human spirit”.

They urged that reality is exhausted by nature, containing nothing “supernatural”, and that the scientific method should be used to investigate all areas of reality, including the “human spirit” (Krikorian 1944; Kim 2003).

So understood, “naturalism” is not a particularly informative term as applied to contemporary philosophers.

However, familiarity with the relevant scientific history casts the matter in a different light.

It turns out that naturalist doctrines, far from varying with ephemeral fashion, are closely responsive to received scientific opinion about the range of causes that can have physical effects.

The self-proclaimed “naturalists” from that period included John Dewey, Ernest Nagel, Sidney Hook and Roy Wood Sellars.

These philosophers aimed to ally philosophy more closely with science.

The modern history of psychology, biology, social science and even physics itself can usefully be seen as hinging on changing attitudes to naturalist ontological principles and naturalist methodological precepts.

This entry, however, will be concerned solely with naturalist doctrines that are specific to philosophy.

The important thing is to articulate and assess the reasoning that has led philosophers in a generally naturalist direction, not to stipulate how far you need to travel along this path before you can count yourself as a paid-up “naturalist”.

As indicated by the above characterization of the mid-twentieth-century American movement, naturalism can be separated into an ontological and a methodological component.