Je pense, donc je suis

As much as I hope we get into chapter six and the way Descartes echoes, or expands upon, Bacon, I think the issues presented in Chapter 4 might be more prevalent in our minds during the first Descartes class, so I thought it might be useful to speak on that.

And noticing that this truth -- I think, therefore I am -- was so firm and so assured that all the most extravagant suppositions of the skeptics were incapable of shaking it, I judged that I could accept it without scruple as the first principle of philosophy I was seeking. --Descartes p.18

It would appear that shortly after this Descartes draws from this assertion the following conclusion:

And having noticed that there is nothing at all in this I think, therefore I am that assures me that I am speaking the truth, except that I could see very clearly that, in order to think, it is necessary to exist, I judged that I could take as a very general rule that the things we conceive very clearly and very distinctly are all true, but that there is merely some difficulty in properly discerning which are those that we distinctly conceive.

It is the most important observation I intend to make in this post that, despite being discovered by Descartes chronologically after his initial premise, this idea is logically prior to his je pense, donc je suis. That is to say, it is impossible to believe that this I think, therefore I am is true unless you first accept that things which we conceive very clearly and distinctly-- such as Descartes saw that cogito, ergo sum distinctly-- are true.

Is this really an acceptable grasping point? Surely there has existed at least one person who has converted from one religion to another, or has in some other way clearly and distinctly perceived something other than he or she clearly and distinctly perceived at an earlier date. Descartes seems to refer to this idea in other places: "anything the knowledge of which was not so natural to our souls that one could not even pretend to be ignorant of it" on page 24, "they are nearly all so evident that it is necessary only to understand them in order to believe them" on page 38, "common sense" and "reason" on page 43.

In what way is this apparent reliance on 'clear and distinct perception' in any way distinct from a confidence in one's beliefs? That is to say, Descartes seems to think he has struck upon something eminently true, and derived from it a system also eminently true. Let us leave his I think, therefore I am aside for a moment and face his most logically prior assumption: he asserts that what each individual sees clearly by reason / common sense to be true, is true. In what way is this distinct from, say, relativism?