The Problem of Induction vs. The method of Radical Doubt
... evidence that supports the conclusion that the sun will rise tomorrow, but Russell points out that there is no way to know if such is true and therefore knowledge. One can only know that it has happened up until now. Even granting that the assumption is true, Hume asks what justification is there to assuming that it is knowledge. He states that “The contrary to every matter of fact is still possible” (p.133). Rene Descartes discusses a different form of skepticism called radical doubt. Descartes proposes that there are three stages to radical doubt. The first stage is the realization that “the senses deceive” (p. 126). An example to illustrate this point is a stick that looks bent in water when it is in fact straight. The second stage of radical doubt is the realization that we may be dreaming for all we know because there are no definite signs that we are not dreaming. Descartes uses the example of himself dreaming about sitting in his bed gown by the fire when in fact he is asleep in his bed to illustrate this stage. The third and final stage is possibly the most radical and is the realization that for all we know there may be a malicious, all powerful demon deceiving us about everything. The first two stages of radical doubt dismiss a posteriori knowledge while the third stage of radical doubt dismisses a priori knowledge. This is knowledge that is acquired solely by reflection and thought. Descartes contends that there is only one thing that can be known when taking radical doubt into consideration. He contends that because one thinks then one must exist. There are both similarities and differences between the two different forms of skepticism. Both forms dismiss a posteriori knowledge even if by different mechanisms. For example, Hume and Russell use the distinction between the past and the future and our inability to predict the future to dismiss a posteriori knowledge while Descartes uses the possibility that our senses deceive us and that we may be dreaming to dismiss a posteriori knowledge. But it is evident that both dismiss this form of knowledge. When each form of skepticism is examined there are differences that become apparent. The problem of induction does not dismiss a priori knowledge while radical doubt does dismiss a priori knowledge. In fact Hume states “the truths demonstrated by Euclid would for ever retain their certainty and evidence” (p.132). However, it is clear that even truths demonstrated by mathematics would not be able to be justified under radical doubt skepticism because of the third stage. Therefore, it can be noted that the problem of induction allows for a priori knowledge while the method of radical doubt does not. It is also evid...