Descartes And Cogito Ergo Sum: The Cartesian Mistake.

You think therefore you are---right? You can't deny that when you think that you exist as something, even if that is some unknowable being. Perception, even the perception of your own thoughts, is a guarantee of existence because to perceive something is the analytic a priori guarantee of being a perceiver. But, it isn't the thought, the content, that determines your existence; instead, it is sensation. Perception always starts with sensation. It is the very foundation---it is perception without form.

This is where Descarte went wrong with his idea of Clear and Distinct Ideas. He thought that if something was clear and distinct, it was  as we see it.  After all, our thoughts are clear and distinct, and what more can guarantee that something is true than similarity to what is sure. Some people think that he is caught in a form of circular reasoning with Clear and Distinct ideas---The Cartesian circle--however, he's not saying that God stamps his stamp of authority on clear and distinct ideas. Clear and Distinct Ideas are sure because the clearness and distinctness of our thoughts is what makes our existence sure. 

However, this is just a missing distinction that probably resulted as a result of lacking the right language. He failed to make the distinction between the form of feeling (thought) and feeling (qualia, presentness, pure consciousness). There can be sensation without thought; but, there cannot be thought without sensation. Sensation is a priori necessary for thought. So feeling, qualia, presentness is always first and formost, metaphysically and epistemically primary. 

He blended simple consciousness and the form of consciousness (thought) into one into a single word or concept and built the rest of his theory on that. The use of that one ambiguous word, Cogito or Thought, that one failed distinction, brought his entire theoretical structure crumbling down.

I think therefore I am should be I feel therefore I am; I think therefore I am should be about qualitativness and not form found as thought; I think therefore I am is a reflection of the form of thought on the qualia. I think therefore I am is a reflection and is the a statement about the reflexive recognition of the qualitative nature. I think therefore I am is simply the the recognition of the presentness of consciousness.

Helpful articles:  
http://plato.stanford.edu/entries/qualia/
http://plato.stanford.edu/entries/consciousness-representational/
http://en.wikipedia.org/wiki/Consciousness
http://plato.stanford.edu/entries/descartes-works/
http://plato.stanford.edu/entries/descartes-ontological/