Upon its first English publication in 1959, Popper’s The Logic of Scientific Discovery revolutionized thinking about the scientific method. Largely an exploration of the “demarcation problem,” or what distinguishes science from non-science, Popper introduced and defended his concept of falsifability – that scientific systems are ones open to empirical disconfirmation – against the prevailing views of his day. Now widely considered among the most important books in the history of philosophy of sc