It is not his possession of knowledge, of irrefutable truth, that makes the man of science, but his persistent and recklessly critical quest for truth.
Karl PopperThe initial stage, the act of conceiving or inventing a theory, seems to me neither to call for logical analysis nor to be susceptible of it.
Karl PopperThere is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life.
Karl Popper