Originally Posted by Dr Livingston
A genius. Perhaps the most influential philosopher of the 20th century. Made monumental contributions to the philosophy of language and logic. Google should be littered with references. His Tractatus Logico-Philosophicus
is a masterpiece and contains the famous quote: "whereof one can not speak, thereof one must remain silent."
Spent a large part of his career trying to define what it is to know
something and relatedly, what it means to be certain