A history of materialism, Part 3: Scientific materialism
The third of a four-part series on Marx's science and epistemology.
This is the third of a four-part series on the history of materialism. The first part is here and the second part is here.
The intellectual history of epistemologies is far more complicated and nuanced than the capsule summary I’ve presented her, but I do so for a reason. In principle, we should be able to place any given theory of knowledge on a spectrum between blind reason and strict empiricism. This is because every epistemology worth the name has to answer a simple question: can we trust the senses? If so, then you move towards one end of the spectrum, and sensory evidence becomes the criterion of legitimacy for any other source of knowledge. If not, then you are forced to rely on other sources of knowledge – reason, intuition, revelation, and so on – while dismissing the senses as unreliable. The figures I have chosen have gravitated towards one end of the spectrum or the other, and if I have simplified their philosophies it has been simply to emphasize their alignment.
But now, I would like to consider someone who doesn’t seem to fit neatly into either category: Epicurus. Ordinarily, Epicurus is understood as a strict empiricist. He declares that “the evidence of our senses…ought to be the rule of our reasoning about everything”; elsewhere, Diogenes reports a clever argument by Epicurus: “If you argue against all your sensations, you will have no criterion to declare any of them false.”
Like Democritus, Epicurus argued that the world was ultimately composed of atoms. Their physics were so similar, in fact, that intellectuals like Cicero writes that “most of it belongs to Democritus,” and cast Epicurus as a kind of plagiarist. But Karl Marx, in his dissertation, rejects Cicero’s characterization and lays out what he sees as The Difference between the Democritean and Epicurean Philosophy of Nature. This argument is crucial for understanding Marx’s materialism.
As atoms travel through the void, Democritus argues, they fall downwards in perfectly straight lines. But this, Marx says, cannot explain anything about the world – for if atoms are moving in parallel “neither their repulsion nor their meeting would have taken place, and the world would never have been created.” But the world does exist, as a matter of empirical fact; thus we can directly surmise that Democritus’s picture is incorrect.
But Epicurean physics, Marx writes, do not fit this picture. For in Epicurus’s theory, atoms, as they fall, can spontaneously deviate from a straight line; and this “declination of the atom from the straight line differentiates one [theory] from the other.” And from this slight motion, Cicero writes, “arose complexities, combinations, and adhesions of the atoms with one another, and out of this came the world, all parts of it and its contents.”
Cicero thinks this “swerve” is a “puerile invention” – an occult force of the sort we have already discussed. Marx disagrees on multiple grounds, but three are relevant here. First, as we have already noted, the empirical existence of the world in all its complexity rules out Democritus’s universe – but it does not rule out the universe of Epicurus. Second, Epicurus works to reconcile the swerve with empirical reality by endeavoring “to represent the declination to be as imperceptible as possible to the senses”. And third, Marx argues, our experience of freedom is something that “must be realised, positively established” by physics; by allowing the atom to spontaneously swerve, Marx argues, its “motion is established as self-determination.”
Democritus’s deterministic universe cannot account for freedom, but the Epicurean universe, because it allows for spontaneity, can.
It is true, then, that Epicurus has departed from what we have called strict empiricism by proposing the existence of an occult force. But this occult force – the spontaneous swerve of the atom – can explain empirical reality in a way that the strict empiricism of Democritus, ironically, cannot. Indeed, the very existence of the world, along with the existence of freedom, have backed Epicurus into having to accept the swerve, for Epicurus, Marx writes, has only one rule: “the explanation should not contradict sensation”.
This is what I will call the philosophy of scientific materialism. It differs from strict empiricism in that it will allow the introduction of “forces” as explanatory hypotheses – thus, it is scientific. But unlike blind reason, scientific materialism will only introduce these forces where senses fail to provide an explanation; and even then, these forces must be consistent with what the senses tell us. Thus, it is materialistic.
Epicurus was in this light the first scientific materialist – but to better understand this doctrine, let us turn to its most important practitioner: Isaac Newton. Writing to a critic in 1972, Newton explains his method directly:
The best and safest method of philosophizing seems to be, first to enquire diligently into the properties of things, and to establish these properties by experiment, and then to proceed more slowly to hypothesis for the explanation of them.
This empirical approach to knowledge may proceed slowly and piecemeal, he admits, but it advances on much sounder footing than blind reason. So he writes in Opticks:
To explain all nature is too difficult a task for any one man or even for any one age. ’Tis much better to do a little with certainty, & leave the rest for others that come after you, than to explain all things by conjecture without making sure of any thing.
As with Locke, Newton’s commitment to empiricism inclined him towards a kind of mechanistic physics, which rid the world of “occult forces” that could not be easily confirmed by empirical inquiry. But ironically, this led him to doubt one of his greatest discoveries: gravity. In a 1692 letter to Richard Bentley he writes,
Tis unconceivable that inanimate brute matter should (without the mediation of something else which is not material) operate upon & affect other matter without mutual contact…That gravity should be…so that one body may act upon another at a distance through a vacuum without the mediation of any thing else…is to me so great an absurdity that I beleive no man who has in philosophical matters any competent faculty of thinking can ever fall into it.
Newton’s doubts were echoed by his contemporaries – most ferociously by Gottfried Wilhelm Leibniz. Though Leibniz was a rationalist, he accepted the mechanistic view of the universe, insisting that “All the natural forces of Bodies are subject to Mechanical Laws…like a Watch”. But if there was gravity, there
Would be an Operation at a Distance…he would have the Sun to attract the Globe of the Earth through an Empty Space? Is it God himself that performs it? But this…is the very Thing which all Men endeavour to avoid in Philosophy…Otherwise nothing will be easier than to account for Any thing by bringing in the Deity, Deus ex Machina, without minding the Natures of Things.
Though Leibniz was, again, a rationalist, this critique fits well within the tradition of strict empiricism; for what he cautions here is that Newton, by appealing to an immaterial force, can make any claim he likes “without minding the Natures of Things.”
Despite such critiques and his own doubts, however, Newton found himself backed into a theory of gravity by the evidence:
In this philosophy particular propositions are inferred from the phenomena, and afterwards rendered general by induction. Thus it was that…the laws of motion and of gravitation were discovered. And to us it is enough that gravity does really exist, and acts according to the laws which we have explained, and abundantly serves to account for all the motions of the celestial bodies, and of our sea.
This is scientific materialism. Newton, like Epicurus, begins with a methodological commitment to empirical investigation; but like Epicurus, he finds that he can only explain certain empirical facts by proposing the operation of some unseen force. What distinguishes the theory of gravity from an exercise in blind reason is that operates as an explanation, not instead of one. It is theoretically productive; it makes predictions, and it can be confirmed by empirical experiment.
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