Sid, you may want to keep your sig under control - it might get you into trouble...
"True knowledge exists in knowing that you know nothing. And, in knowing that, you know nothing, that makes you the smartest of all." -- ***censored***.
If you
know you know nothing - then you
know something. By definition.
The non sequitur which follows "And, in knowing that" is a linguistic back-flip with reverse double-pike into "you know nothing" which, without the punctuative comma would have made perfect sense, and indeed, unconsciously achieves precisely that effect, leaving you bewildered, but unwilling to think too deeply about the meaning as you've just had your ego massaged by the closing flattery of being "the smartest of all" which of course was never the real intent of the quote originator - quite the reverse, and carried out for his own perverted pleasure.