Issue 3 (March 2005)

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abstract

Epistemic externalists offer many arguments against skepticism. They modify the skeptic’s concept of knowledge, justification and meaning and point out which of his presuppositions we need not accept. Dretske claims that a skeptic wrongly presupposes that we cannot know if we do not know that we know. But knowledge need not be self-conscious (consider small children and animals). According to Nozick a skeptic wrongly presupposes the Principle of Closure (knowledge is closed under logical implication). He says that although we do not know that we are not brains in a vat, a skeptic does not have the right to use this principle to argue that we do not know things that are obvious. According to Putnam the skeptical hypothesis that we are brains in a vat is incoherent when we use the external theory of meaning. If the meaning of our words depends on a causal relation with our environment, the sentence “I am a brain in a vat” is false or meaningless. Similarly, Davidson says that the external theory of perceptual beliefs excludes global skepticism. According to Williams skepticism simply presupposes a stance opposite to externalism, namely internalism (self-consciousness is privileged and all justifying factors must be introspectively accessible). When we reject internalism, no skeptical argument can be formulated.