Cogito ergo sum

"I think, therefore I am." is probably the most famous philosophical statement due to it's simple argument and compelling conclusion. So when I heard that it is a fallacy because it is a circular argument, I was highly curious to find out for myself how true that claim is.

A simple google search revealed the following at: http://www.sjsu.edu/depts/itl/graphics/adhom/circular.html, a philosophy webpage of San Jose State University.

I quote: "Descartes has begged the question here, because when he said "I think," he'd already implied "I am" (or how else could he think?). Yet his fallacy continues to persuade people, over three hundred years later."

Wow.. what a big claim. But interestingly, instead of overturning the "fallacy", the author of the webpage (let's call him Sjsu) is actually supporting the argument. Here's why:

Sjsu says "when he said "I think," he'd already implied "I am" (or how else could he think?)"

This is a proposition. And we can we rephrase it into: If I can think, I am.

And of course if that premise is true, then the conclusion: "I think, therefore I am." is definitely true as well. It is a very simple deductive argument.

In summary:

(1) If I can think, I am.

(2) I think, therefore I am. (1)