Publisher Summary This chapter discusses induction and the empiricist model of knowledge. Empiricism can be described as that philosophical position which holds that experience is the only source and the only justification for all synthetic knowledge. All descriptive concepts are taken from experience, and all statements about the world are derived from it. Referring to empiricism in its modem form, these two principles can be formulated thus: (1) the language of the natural sciences contains only observation terms as undefined descriptive terms and (2) all (true) synthetic statements can be and can only be justified by observation sentences. The different ways of justification of empirical sentences by observation sentences is discussed. The inductive procedure of validation, and the empiricist thesis can only be upheld if a theory of induction can be constructed, which explains in a satisfactory way how one arrive (by a process of inductive reasoning from observations) at those of empirical hypotheses that have not been verified and are not favored against their competitors by their corroboration.