Why Descartes thinks he needs a completely clean slate to start his enquiry in Meditation 1.

The notion of a clean slate as a basis or starting point have been strong roots in philosophical thinking for decades. Some noted philosophers applying this notion to their thinking are none other than Descartes himself as well as John Locke, who's "Tabula Rasa" proposition is well known. It should be noted that Descartes' "clean sate" is different to the Tabula Rasa as suggested by Locke in the sense that Descartes is referring to clearing …

…on firm soil. In the same way, I began by taking everything that was doubtful and throwing it out, like sand ... (Replies 7) Only through undermining these foundations and causing whatever that had been built on them to crumble of its own accord, will he be able to begin, and establish firm and lasting knowledge built on the basis of absolute truths. This is why Descartes feels the importance to start with a completely clean slate.