:UNM is a nice place.  I enjoy the neighborhood. 
 :As to logic:  Yeah, that wasn't quite the place to discuss it. 
 :I firmly believe that logic is one of three fundamentals of the universe, the other two being causality and existence, and everything that we know is a mixture of these.  See my blog on the topic, Triessentialism.  Logic is irreducible; the word "prove" described a concept peculiar to logic (and fields which rely upon it, such as math and law).  It is as ludicrous to talk about proving something without logic as it is to talk about color in the dark. 
 :However, you made an interesting statement: "assuming that circularity diffuses any statement" 
 :Circularity doesn't diffuse anything, it just doesn't imply anything.  For example, if I said "1+1=2, therefore 2=1+1", I haven't proven anything, ie, I haven't derived another statement that is substantively different from the first.  However, "1+1=2, therefore 1+1+1=1+2" is not circular, it is derivative. 
 :Here's another twist of circularity.  You said that because using logic to prove logic is circular, we cannot know anything.  Did you use logic to come up with that? 
 :One more for the road:  "We cannot know anything."  To assume that this sentence is true implies that you know this sentence, and therefore you know something, and therefore this statement is false.  However, you can say what DeCartes said:  "I doubt, therefore I think.  I think, therefore I am."