Fifth reprint from the second edition revised (London : K. Paul, 1932). – This book is an attempt «to plunge into the philosophy of early modern science, locating its key assumptions as they appear, and following them out to their classic formulation in the metaphysical paragraphs of Sir Isaac Newton. The present is a brief historical study which aims to meet this need» (p. 22). – Chapter I, Introduction : A. The historical problem suggested by the nature of modern thought; B. The metaphysical foundations of modern science the key to this problem; – Chapter II, Copernicus and Kepler : A. The problem of the new astronomy; B. Metaphysical bearings of the pre-copernican progress in mathematics; C. Ultimate implications of Copernicus’ step. Revival of pythagoreanism; D. Kepler’s early acceptance of the new world-scheme; E. First formulation of the new metaphysics. Causality, quantity, primary and secondary qualities; – Chapter III, Galileo : A. The science of “local motion”; B. Nature as mathematical order. Galileo’s method; C. The subjectivity of secondary qualities; D. Motion, space, and time; E. The nature of causality. God and the physical world. Positivism; – Chapter IV, Descartes : A. Mathematics as the key to knowledge; B. Geometrical conception of the physical universe; C. “Res extensa” and “Res cogitans”; D. The problem of mnd and body; – Chapter V, Seventeenth-century english philosophy : A. Hobbes’ attack on the cartesian dualism; B. Treatment of secondary qualities and causality; C. More’s notion of extension as a category of spirit; D. The “spirit of nature”; E. Space as the divine presence; F. Barrow’s philosophy of method, space, and time; – Chapter VI, Gilbert and Boyle : A. The non-mathematical scientific current; B. Boyle’s importance as scientist and philosopher; C. Acceptance and defence of the mechanical world-view; D. Value of qualitative and teleological explanations; E. Insistence on reality of secondary qualities. Conception of man; F. Pessimistic view of human knowledge. Positivism; G. Boyle’s philosophy of the ether; H. God’s relation to the mechanical world; I. Summary of the pre-newtonian development; – Chapter VII, The metaphysics of Newton : Section 1, Newton’s method; Section 2, The doctrine of positivism; Section 3, Newton’s general conception of the world, and of man’s relation ti it; Section 4, Space, time, and mass; Section 5, Newton’s conception of the ether; Section 6, God. Creator and preserver of the order of the world; – Chapter VIII, Conclusion : Need for philosophy as a critical analysis of the metaphysic of science. M.-M. V.