An explicit philosophy and meta-philosophy of positivism, empiricism and popperianism is provided. Early popperianism is argued to be essentially a form of empiricism, the deviations from empiricism are traced. In contrast, the meta-philosophy and philosophy of an evolutionary naturalistic realism is developed and it is shown how the maximal conflict of this doctrine with all forms of empiricism at the meta-philosophical level both accounts for the form of its development at the philosophical level and its defense against attack from nonrealist (...) quarters. Following an earlier article on realism of similar theme (Synthese 26 (1974), 409) this paper then further explores the ramifications of a thoroughgoing realist position. (shrink)