MODERN RATIONALISM
Descartes and Hobbes were the founders of modern rationalism, but each in a different way. Descartes (1596-1650) found mathematics a model of procedure. In other words, he proposed that men should philosophize after the manner of mathematics. He did not believe that mathematics, with its applications to physics, was itself the highest knowledge. He sought rather to formulate a logic that should be as exact as mathematics, but more fundamental and universal; thus affording a basis for the demonstration of the higher truths concerning God and the soul. The “Discourse on Method”〖H. C., xxxiv, 5.〗 is a record of the author’s profound regard for mathematics and of his own search for a like certainty in philosophy.
But Hobbes (1588-1679) was a follower of Galileo in a different sense. He proposed not so much to imitate mathematics as to adopt and extend it. He represents that idea which La Place so eloquently proclaimed a century later, and which the work of Newton seemed so nearly to realize, the idea of a universal mechanism, in which the laws of bodily motion should apply even to the origins of nature and to man. It was hoped thus to bring it about that all things should be as demonstrably known, and as certainly predictable, as the velocities and orbits of the planets. To this end the author of “The Leviathan”〖H. C., xxxiv, 311.〗 regards both man and society, the little man and the giant composite man, as simply delicate and complicated mechanisms, moved by an impulse of self-seeking.
These, then, are the three forms in which the science of the Renaissance as embodied in Galileo is communicated to modern philosophy. Bacon, Descartes, and Hobbes became in turn the sources of the new tendencies that make up the philosophy of the seventeenth and eighteenth centuries. The empiricism of Bacon was renewed in Locke,〖H. C., xxxvii, 9.〗 who applied “the plain historical method” to the study of the human mind; continued by Berkeley,〖H. C., xxxvii, 189.〗 who reduced even being to perception (“esse est, percipi”); was brought to a sceptical crisis in Hume;〖H. C., xxxvii, 289.〗 but persisted as the national philosophy of England. The rationalism of Descartes afforded a basis for the great metaphysical systems of Continental philosophy, for the monism of Spinoza and the pluralism of Leibnitz; was degraded to a mere formalism and dogmatism in Wolff; but nevertheless persisted in the new idealistic German philosophy which was inspired by Kant. The physical philosophy of Hobbes, mingled with similar elements drawn from the philosophies of Locke and Descartes, developed into the French materialistic movement which attended the outbreak of the Revolution, and remains the model for all philosophers who seek to make a metaphysics out of physics. The forms which these three tendencies assumed during the eighteenth century, and especially their excessive emphasis on facts and necessities, provoked the great reaction which bore fruit in the following century, but which was already anticipated in Pascal’s philosophy of faith,〖H. C., xlviii.〗 in Rousseau’s philosophy of feeling,〖H. C., xxxiv, 165.〗 and in Lessing’s philosophy of development.〖H. C., xxxii, 185.〗