Descartes: wax argument & knowledge

Descartes uses his wax argument, as described in my previous post, to construct a system of knowledge. He considers his perceptions to be unreliable, as he discovered in his wax argument, and he discards them completely when determining what he should base his knowledge on. He decides that only deduction can be used as a method for obtaining knowledge. At this point, Descartes brings God into his argument and decides that he must trust his senses at least a little bit. After all, God provided him with a working mind and sensory system. And, since God is benevolent, he does not desire to deceive Descartes in any way. Further, he believes that there is an external world because perceptions come to him involuntarily, and the things that he perceives must be external to his senses. From this, he finally entertains the idea that it may be possible that he may acquire knowledge about the world through both deduction and perception. Descartes further argues that knowledge is represented in the form of ideas and that rational knowledge is incapable of being destroyed.