Isaac Newton: The Last Sorcerer. Michael White

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      It was these experiments that convinced Galileo that Aristotle’s idea of the Unmoved Mover was false. Objects do not move because they are constantly being pushed or pulled: rather, they possess inertia – an innate tendency to move unless stopped.

      This was a revolutionary notion, but his views on other questions concerning matter and energy also entitle Galileo to be seen as the first of the modernists. He rejected Aristotle’s idea of the four elements and subscribed to Democritus’s atomic theory at least three decades before it began to make a reappearance in the schemes of Europe’s leading thinkers, though he was unable to prove it. He also flew in the face of Aristotle’s insistence that objects possess integrally all the properties we sense when we observe them, declaring:

      I feel myself impelled by necessity, as soon as I conceive a piece of matter or corporal substance, of conceiving that in its nature it is bounded and figured by such and such a figure, that in relation to others it is large or small, that it is in this or that place, in this or that time, that it is in motion or remains at rest, that it touches or does not touch another body, that it is single, few or many; in short by no imagination can a body be separated from such conditions. But that it must be white or red, bitter or sweet, sounding or mute, of a pleasant or unpleasant odour, I do not perceive my mind forced to acknowledge it accompanied by such conditions; so if the senses were not the escorts perhaps the reason or the imagination by itself would never have arrived at them. Hence I think that those tastes, odours, colours etc. on the side of the object in which they exist, are nothing else but mere names, but hold their residence solely in the sensitive body; so that if the animal were moved, every such quality would be abolished and annihilated.⁵

      So, contrary to Aristotle, Galileo states categorically that there are two distinct qualities of bodies. The first may be considered primary qualities, which are inseparable from and fundamental to the nature of the object in question – what twentieth-century scientists would ascribe to the atomic structure and chemical nature of an object. The others are secondary qualities, which are interpreted by the senses of the observer.

      These revolutionary notions of Galileo’s – ideas which have perhaps been swamped by his more famous discoveries in astronomy and dynamics – greatly influenced the French philosopher René Descartes, who for a time informed Newton’s thinking on the subject of matter and the nature of the physical universe.

      Descartes is most famous today for two developments – Cartesian coordinates, which still play a key role in mathematics, and dualism, a philosophy which proposes a sharp distinction between body and soul, matter and spirit. According to Cartesian dualism, the spirit is personal and nebulous, and matter must therefore be impersonal and concrete.

      In Descartes’s image of the universe, matter is immersed in an unseen, immeasurable medium called the ether. God endowed the universe with movement at the beginning of time and allows it to run spontaneously but in accordance with his will. Because in this scheme matter fills all of space, there can be no such phenomenon as a vacuum and all motion is produced by matter impressing on other matter within the medium of the ether. Descartes expressed this in his famous theory of vortices, in which he pictured movement, such as the fall of a stone to the earth, as being like the movement of a feather or a straw caught in an eddy or a whirlpool.

      Descartes rejected mysticism and the occult in his writings and visualised the universe as a machine. Every action involving matter was purely mechanistic, and matter had no contact with spirit. To Descartes, all animals – including humans – were also mere machines. Humans had a spiritual aspect, a soul, but this had no link with our physical selves.

      These ideas were highly controversial. On a scientific level, Descartes’s concepts were unverifiable and he did not contrive experiments to support his theories. On a superficial level, his vortex theory did not clash with the doctrines of Galileo, in that it did not contradict experimental evidence. Galileo had shown that, because of inertia, all movement continued until stopped, and Descartes proposed that the universe had been set in motion by God. The two ideas were not incompatible: if we assume the Creator set things in motion, they would continue until stopped by, say, the intervention of mortals.

      But the most radical aspect of Cartesian philosophy was that it implied to many that, once the universe had been set in motion, God was no longer needed. The Creator had been effectively demoted from ‘Supreme Good’ to ‘First Cause’. Naturally this was a view hotly disputed by theologians and the majority of philosophers, many of whom had been brought up on Aristotle and still thought along the same lines as the Scholastics of the thirteenth century.

      Descartes died when Newton was eight years old, but his philosophies were becoming immensely fashionable as Newton entered university and extended his reading beyond the curriculum. Because it contained material referring to his disputed theories of divine function in a mechanical universe, Descartes’s most famous book, Discourse on the Method (published in 1637), was unpopular with the ecclesiastical authorities, but his theories were discussed openly in the more liberal universities of Europe and began to spread.

      As Descartes’s theories of dualism became known, three other philosophers were helping to create the intellectual scene to which Newton would add his own unique ideas.

      Pierre Gassendi, who was a Catholic priest and a close contemporary of Descartes, revived the work of Democritus and proposed an atomic theory in which matter was composed of tiny indivisible parts. Unlike Descartes, Gassendi did not attempt to describe a mechanistic universe in which all action on a fundamental level occurred by way of vortices – a theory which for many people marginalised God. Instead, he envisaged a universe composed of Democritus’s atoms presided over by an all-pervading Creator. Gassendi’s outlook has been dubbed ‘Christianised atomism’, because it maintains an omnipotent and omnipresent role for God. This was more acceptable than Descartes’s model to men like Newton, who sought a mechanistic model for the universe but could not countenance any diminishing of the Creator’s position.

      Another great innovator of the time was Robert Boyle, today seen as the supreme experimentalist of his era. Boyle believed in practical analysis and was more concerned with how a phenomenon occurred rather than why it happened.

      Boyle tried to unite elements of Descartes’s philosophy of a mechanistic universe with the revived atomic theory, but he did not subscribe to the contention that God had no role in the physical world after initiating primal movement. Like Gassendi, he held that God’s ‘general concourse’ was continually needed to keep the mechanical universe working. But a greater contribution to the study of matter and energy was his demonstration of the fallacy of Aristotle’s notion of the four elements.

      In one of these displays, Boyle illustrated how fire could not be considered a basic element and that Aristotle’s claim that fire could resolve things into their elements was false. He demonstrated that, contrary to Aristotle’s belief, gold can withstand fire and can also be alloyed with other metals and then recovered in its original form, suggesting the existence of unalterable ‘corpuscles’ of gold. He also showed that even when fire did break down materials it required different degrees of heat and different time periods to succeed, and more often than not it produced new substances that were also complex. Finally, he showed that some materials could not be reduced by fire alone.

      The last of the major seventeenth-century figures who greatly influenced Newton’s intellectual development was Francis Bacon. Bacon was not solely a philosopher. He was Lord Chancellor under James I, and was an essayist and moral philosopher who wrote widely about the way he thought science should be conducted. In his The Advancement of Learning (1605), The New Organon (1620) and especially The New Atlantis (1627), he criticised the blind pursuit of Aristotelian philosophy and the rote-learning system of the СКАЧАТЬ