Summary:
There are two ways philosophers look at knowledge:
     1) Humans can know everything
     2) Humans can know nothing
Most philosophers don't agree with either.  Firstly, they think there is a finite amount of knowledge one can know, and secondly, we at least know some things. The idea of knowing nothing is called skepticism. Most skeptics have to watch how they share their theory that knowledge is non-existent because saying that they "know" that it is true would be contradicting their claim.
Rene Descartes examined certainty and its roots. There is indubitability, the absence of possible doubt about correctness, and infallibility, the absence of any real possibility of error. (Moser , Mulder & Trout, 1998)
Analysis:
After reading about the different ways of interpreting knowledge, I can't say I agree with either theories. How can one have no knowledge at all yet still write and study various theories? But, how can one prove that that is knowledge and not imagined?
Citation:
Moser , P., Mulder, D., & Trout, J. (1998). The theory of knowledge. (pp. 5-9). New York, NY: Oxford University Press, Inc.