In an earlier post on Einstein, I discussed Newton’s demolition of the mechanical philosophy. Since the topic of materialism is so widely misunderstood, I think the significance of what Newton did should be discussed at length. Unfortunately, the revolutionary import of what Newton did has still not been absorbed by many people, even after the lapse of over 300 years. (Newton obviously had nothing to do with Quantum Theory. The reason I have used the words ‘Quantum Revolution’ in the title are to underline the fact that what Newton did, was considered by everyone (including himself) to be as exotic, mind-boggling and non-sensical, in his time, as Quantum Mechanics is considered in our day. This is a fact that is forgotten even by many physicists who describe Newton’s physics as ‘common-sense’ physics, which it was anything but).
Newton, like Galileo and Descartes before him, was an adherent of the mechanical philosophy. According to this philosophy, the goal of science was to explain everything in terms of contact among physical/material bodies. The reasoning behind this approach was solid. Descartes and company were thoroughly dissatisfied with the Aristotelian way of explaining things, whereby phenomena could be explained based on the qualities of the bodies involved.
For instance, according to an Aristotelian, a heavy body fell down because it was going to its natural place. The eminent figures of the modern scientific revolution recognized the emptiness of such an explanation. Therefore, they called for a mechanical approach for intelligible explanations. (The word intelligible is very important here. It is important because the standards of intelligibility have changed, diminished in fact, as science has progressed). Simply put, lumps of matter interacting with other lumps of matter was an ‘intelligible’ explanation for natural phenomena (according to the followers of the mechanical philosophy). So everything from magnetic attraction to gravity had to be explained in mechanical terms, i.e., lumps of matter pushing against each other. Come to think of it, it makes perfect sense. Consider mundane examples such as a footballer kicking a football or people pushing against each other. Both acts of contact give rise to natural phenomena: the football being hurled high into the sky, and the colliding people falling back or down.
The scientific leap made by the adherents of mechanical philosophy was to extrapolate contactual causes for explaining all phenomena, including those where such collisions were not visible to the senses. So for example, in order to explain magnetic attraction and repulsion, Descartes supposed that tiny, invisible particles of matter collided with each other to produce magnetic effects. Gravity too could be explained in a similar way.
But along came Newton and talked about the attractive force of gravity, without giving any intelligible (i.e., mechanical/physical/material) explanation for it. So this essentially meant, anathema of all anathemas, that action could occur at a distance without any physical contact! Dear Reader, we have grown up with a model of the world in which every body in the universe attracts every other body. This might seem common-sense to us but it is anything but. It is like saying that when I move my hand, I move the moon*. Let me rephrase: It is EXACTLY like saying that when I move my hand, I move the moon! Action at a distance! Force! Magic? Intelligibility down the drain!
When Newton published his work, it scandalized such illustrious people as Leibniz (Leibniz is someone who can easily give any intellectual a run for his or her money, in any era), Huygens (another heavyweight), Robert Boyle, and last but not the least Newton (the greatest scientist of them all) himself.
Huygens and Leibniz explicitly rejected Newton’s “mystical” theory because it was “incompatible with the laws of mechanics”. They criticized him for reintroducing “occult” forces into science, from which science of course had extricated itself after great advancements. They felt the that theory of gravitation was a “treason against the good cause of natural science”
And the most striking judgement came from the supreme philosopher, David Hume. Hume said: “Newton restored nature’s ultimate secrets to that obscurity, in which they ever did, and ever will remain” !!!??? Hume was of course right! But this is not what we say about Newton these days, is it? Or even contrast Hume with someone from the same generation, Alexandre Pope, who was a poet (and not a philosopher or a scientist). Pope waxed lyrical about Newton: “Nature and nature’s laws lay hid in Night/God said, ‘Let Newton be!’ and all was light”
Due to the success of Newton’s theory in accounting for experiential and experimental data, it was Pope’s judgement on Newton, rather than Hume’s, which came to be commonly accepted. Newton’s theory became standard, and gradually became ‘common sense’. We discovered that we had to lower our standards of intelligibility. Things could not be explained in physical/mechanical/material terms. After Newton there was no longer any meaningful definition of the term physical or material. Was the force of gravity “physical”/ “material”? In fact, as science progressed further after Newton, with concepts such as electrical and magnetic “fields”, and later on concepts as exotic as “curved space time”, becoming comfortable tools in the toolbox of scientists, the notion that the world is ‘physical’ (whatever that means) forever disappeared from the sciences.
But this is something that many people (including many philosophers and scientists) either do not remember or do not seem to be cognizant of. (Of course, with Quantum mechanics, we have had to further lower our standards of intelligibility).
(Endnote: The ideas in this post have been inspired by the writings of Steven Weinberg, Noam Chomsky, I. Bernard Cohen and Peter Dear)
* This sentence is due to Noam Chomsky