New evil demon

From Wikipedia, the free encyclopedia

The New evil demon is a thought experiment in philosophy that is used to criticise externalism about justification. Formulated by Stewart Cohen, the thought experiment involves an evil demon much like the one introduced by Descartes to motivate skepticism about the external world.

We are asked to imagine a case in which a malicious demon removes a group of people completely from their normal environment, while inducing in them sensory experiences that make it seem to them as if nothing has happened. To many, it seems as if the individuals being deceived are no less rational in the beliefs they form after the demon secretly abducts them than they were before. This is a challenge to externalist positions, such as reliabilism. According to such positions, for a belief to be justified requires that it was formed by reliable mechanisms or that it was based on veridical sense experiences, however, it is specified in this case that these individuals' beliefs were not so produced.

In other words, this thought experiment is a purported counterexample to a type of externalist position. It relies on the intuition that the deceived individuals are as well justified as they were before.

There are a variety of potential responses to the objection. Apart from biting the bullet and accepting the result that those individuals are no longer justified, externalists can (and have) attempted to develop versions of their position which do not commit them to the claim that the deceived individuals are no longer justified.