For the purposes of this paper, realism is defined as the belief that in visual perception there is a direct perception of material bodies existing in space external to the perceiver's body. Most contemporary positivists and analytical philosophers are realists in this sense. Included in this classification would be all those who argue from the character of seen relations of bodies to the uniformity view of causation; those who oppose public to private experience; those who believe that one can point (...) to facts; those who believe in the real existence of objects like extended solid tables and chairs; and those who distinguish in terms of verifiability between judgments of color and judgments of value. (shrink)

This book, first published in 1936, divides into roughly two parts: a re-examination of historical material; and a positive theory of causation suggested by the results of this re-examination. The historical study discloses an ambiguity in the meanings of causation and determinism; it discloses also that this ambiguity is transferred to the meaning of freedom.