Why did Descartes employ Skepticism in his search for knowledge?

One important aspect of Descartes epistemology is the reason for which Descartes employed the method of doubt in an attempt to reach knowledge. Although it may appear that Scepticism is incompatible with the search for knowledge Descartes' reason for employing this method may be explained in two ways. Firstly, one must consider the contextual placement of The Meditation as a reaction to Aristotelian philosophy. Descartes' aim of establishing something 'Firm and lasting' in the sciences must be placed, as Margaret Wilson points out, as a rejection of the prevailing Aristotelian philosophy that holds that the senses are the primary source of knowledge. Thus Descartes must withdraw from the evidence of his senses through subjecting the foundations of his beliefs to skeptical attack, so that he can establish reason alone as the only certain font of knowledge. Furthermore this means that Descartes cannot exam his beliefs piecemeal, in light of other beliefs, as they are already formed within the Aristotelian framework. For Descartes to truly establish his goal of establishing lasting in the sciences he must employ skepticism to remove himself from the context of Aristotelian Philosophy.The second reason for Descartes' use of Skeptic methods concerns the nature of the beliefs he is trying to arrive at. As Frankfurt points out the Mediator embarks on 'the Project of Pure Inquiry' and as such all normal considerations for arriving at knowledge can be dispensed with. Descartes aim to arrive at knowledge that is perfectly certain and indubitable. Yet, in order to do this Descartes must employ a radical 'sorting procedure, as Catherine Wilson calls it, to separate beliefs to which he can assent and those which he must reject. Within the project of pure inquiry this sorting procedure must reject any belief that can even be slightly doubted, and as such Descartes' uses Skepticism to call everything that can be doubted into doubt.