To give a causal explanation of an event means to deduce a statement which describes it, using as premises of the deduction one or more universal laws, together with certain singular statements, the initial conditions ... We have thus two different kinds of statement, both of which are necessary ingredients of a complete causal explanation.
Karl PopperCriticism of my alleged views was widespread and highly successful. I have yet to meet a criticism of my views.
Karl PopperThe scientific tradition is distinguished from the pre-scientific tradition by having two layers. Like the latter, it passes on its theories; but it also passes on a critical attitude towards them.
Karl PopperPiecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology.
Karl PopperOptimism 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 Popper