Optimism is a duty. The future is open. It is not predetermined. No one can predict it, except by chance. We all contribute to determining it by what we do. We are all equally responsible for its success.
Karl PopperThere is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life.
Karl PopperThere will be well-testable theories, hardly testable theories, and non-testable theories. Those which are non-testable are of no interest to empirical scientists. They may be described as metaphysical.
Karl PopperCriticism of my alleged views was widespread and highly successful. I have yet to meet a criticism of my views.
Karl Popper