Maurice Blondel’s major work L’Action contains one of the most penetrating investigations ever of the natural sciences and their methodology. This study examines in detail this discussion of the sciences in its historical and systematic contours. It further clarifies the scientific character of Blondel’s more general philosophy and should be of interest to philosophers of religion and those natural scientists interested in examining the foundations of modern science. In particular it clarifies precisely the interaction at the philosophical level between science and religion. It demonstrates clearly that when one remains consequent in the strictest application of the scientific method, one is forced not only to address the complex matter of consciousness and self-reference, but also such issues as freedom, morality, metaphysics and the more fundamental question of God.