A property of any proposition for which it is possible to specify a set of circumstances the occurrence of which would demonstrate that the proposition is false. According to Karl Popper, falsifiability is the crucial feature of scientific hypotheses: beliefs that can never be tested against the empirical evidence are dogmatic.
(Via Philosophical Dictionary)
Here’s a fine blog post by Doug Geivett on books he recommends for gaining a good grasp of contemporary epistemology (theory of knowledge). In his own courses, Dr. Geivett prefers
These books complement each other nicely. The book by Robert Audi will require a tutor for most who are new to the subject. It is rich and comprehensive, and, most important, very sensible about the topics it addresses. Better than any other book I know of, this book presents the subject in a natural order that is conducive to proper progress through to thorny issues it addresses.
To anchor a course in epistemology, I’ve found that the books by Feldman and Bon Jour complement each other neatly. They are concise and readable surveys of major topics. Laurence Bon Jour adopts a method of presentation that he explains clearly at the outset. While I think the method he adopts is unfortunate, it does give readers a sense of the rootedness of trends in contemporary epistemology in the influential work of the great 17th-century philosopher René Descartes. Of special value is Bon Jour’s treatment of the contest between foundationalists and coherentists in epistemology. A convert from coherentism to foundationalism, Bon Jour excels in his exposition of this debate; yet he is also realistic about the persistent philosophical challenges raised by foundationalism . . . (continue reading)