Descartes way to achieve assurance was to initiate by doubting absolutely everything. The belief or principle or general truth would have to be impossible to doubt; its assurance would have to be eventual and not contingent upon any other belief, and it would have to indicate to something actually existing if the existence of other things in the world were to be concluded from it. Descartes examined his beliefs by groups or classes to observe if he could find one that was impossible to doubt. He began to examine those beliefs based on sense perceptions, deducing in the eventual that they were unreliable and therefore couldn't lead to certain knowledge . In regards to the wax example, the wax example exemplifies how knowledge cannot fundamentally
