Mechanism (philosophy) - Universal Mechanism

The older doctrine which we have called universal mechanism is a theory about the nature of the universe, closely linked with the early modern version of materialism. Universal mechanism held that the universe is best understood as a completely mechanical system—that is, a system composed entirely of matter in motion under a complete and regular system of laws of nature. The mechanists understood the achievements of the scientific revolution to show that every phenomenon in the universe could eventually be explained in terms of 'mechanical' laws: that is, in terms of natural laws governing the motion and collision of matter. It follows that mechanism is a form of thorough going determinism: if all phenomena can be explained entirely through the motion of matter under physical laws, then just as surely as the gears of a clock completely determine that it will strike 2:00 an hour after it strikes 1:00, all phenomena are completely determined by the properties of that matter and the operations of those natural laws.

Indeed, the determinism implied by universal mechanism is even stronger than clockwork.

Whereas the mechanism of a clock may cease to work predictably as its parts break down, the "parts" of the system in universal mechanism are nothing less than everything in the universe — anything that they "broke down" into would still be a part of the universe, and so would still be subject to the mechanistic laws of nature.

The French mechanist and determinist Pierre Simon de Laplace formulated the sweeping implications of this thesis by saying:

"We may regard the present state of the universe as the effect of the past and the cause of the future. An intellect which at any given moment knew all of the forces that animate nature and the mutual positions of the beings that compose it, if this intellect were vast enough to submit the data to analysis, could condense into a single formula the movement of the greatest bodies of the universe and that of the lightest atom; for such an intellect nothing could be uncertain and the future just like the past would be present before its eyes." Pierre Simon Laplace, A Philosophical Essay on Probabilities

One of the first and most famous expositions of universal mechanism is found in the opening passages of the Leviathan by Thomas Hobbes (1651). What is less frequently appreciated is that René Descartes, who is today remembered mainly as a paradigmatic enemy of materialism and mechanism (and in that respect quite the opposite of Hobbes), also did much to advance the mechanistic understanding of nature, in both his scientific works on mechanics and in his philosophical works on metaphysics.

Descartes was a substance dualist, and argued that reality was composed of two radically different types of substance: corporeal substance, on the one hand, and mental substance, on the other hand. Descartes steadfastly denied that the human mind could be explained in terms of the configurations of corporeal substance (a chief claim of all forms of mechanism). Nevertheless, his understanding of corporeal substance was thoroughly mechanistic in nature:

"I should like you to consider that these functions (including passion, memory, and imagination) follow from the mere arrangement of the machine’s organs every bit as naturally as the movements of a clock or other automaton follow from the arrangement of its counter-weights and wheels." (Descartes, Treatise on Man, p.108)

His scientific work was based on the understanding of all natural objects, including not only billiard balls and rocks, but also non-human animals and even human bodies, as completely mechanistic automata. Descartes' dualism was, in no small part, motivated by the fact that he could see no place for the soul or for freedom of the will in his thoroughly mechanistic understanding of nature. Ancient naturalists such as Aristotle, on the other hand, had no need for substance dualism because their conception of nature was teleological rather than mechanistic, and was compatible with a robust sense of human freedom. Descartes, then, can be seen as agreeing with the early modern mechanists, and disagreeing with Aristotle, on the nature of the physical world. The difference between Descartes and his mechanist colleagues was that mechanists either saw no problem for the notions of soul and freedom of the will, or else were simply willing to dispense with these notions altogether.

The mechanistic worldview gained considerable favor with the revolutionary successes of Isaac Newton, whose work in mechanics seemed to successfully explain the motion of both celestial bodies and earthly objects according to the operation of a single mechanical principle. To be sure, that principle — universal gravitation — was something of a disappointment to the older cadre of mechanists, since mechanism originally sought to explain all phenomena entirely in terms of the motion and collision of material bodies, whereas Newton's principle of gravitation required action at a distance. Nevertheless, the generation of philosophers who were inspired by Newton's example carried the mechanist banner. Chief among them were French philosophers such as Julien Offray de La Mettrie and Denis Diderot (see also: French materialism).