Knowledge, for the epistemic skeptic, has had a long running tradition of being unattainable. From René Descartes, one of the greatest exemplars of the skeptical approach to epistemology, we have inherited the idea that any grasping for knowledge by way of the senses is vanity.
In Book I of his Meditations, Descartes finds that he is unable to free himself from the thought that he is dreaming – even in the moment of his writing. Descartes pushes the idea further, proposing that there is a malignant demon who is “exceedingly potent and deceitful, [who] has employed all his artifice to deceive” him — leading Descartes to the devastating conclusion that one can know nothing about the external world outside of one’s mind. (Essentially, one can never truly know that he or she is not in the Matrix.)
Philosophers, such as Barry Stroud, have criticized Descartes on this solipsistic view of knowledge – challenging that if Descartes is right in his insistence that knowledge of the world around him can only be attained through the knowledge that he is not dreaming, then surely Descartes (by his own admission) has no such knowledge; even such a thought could be the product of the dream, could it not?
Stroud, like many philosophers, seems to find the prospect unsatisfactory that one might be unable to know anything about the world around us — and this feeling is well placed and commonly experienced, leading many philosophers to feel that we should merely not invite skeptics to the party. But this does not make the skeptic wrong.
What seems to be most appealing and most unattractive about the skeptical approach to epistemology is that it is unbeatable. Unlike science wherein one requires a falsifiable hypothesis in order to progress further in its study, in philosophy there are advantages to arguing with unbeatable arguments.
At its worst, it presents knowledge as a moving goalpost — the threat of which renders any pursuit of knowledge as merely a chasing after the wind — discouraging a would-be philosopher to take up horsemanship instead.
At its best, however, philosophers can consider the skeptic an always-ready opponent, a challenger, with whom they can spar and strengthen their arguments — showing that the skeptic is useful. Furthermore, there are some things resembling those of epistemic virtues in regards to the skeptical approach — in that it allows one to be humble in what he or she believes (preventing hubris) as well as pushing one to question his or her deepest held beliefs (preventing dogma).
In The Problem of the External World, Stroud argues that the “consequences of accepting Descartes’s conclusion as it is meant to be understood are truly disastrous,” but I am convinced that even with the fractalized, unattainable form of knowledge posited by the skeptic — epistemology and philosophy as a whole can continue to progress. The antipathic attitude adopted towards the skeptic is what makes him so invaluable to the philosopher. The fruit of this antipathy is the reason why skeptics should always be invited to the party.