r/DeepThoughts • u/SummumOpus • 1h ago
“Common sense” obscures our metaphysical assumptions
We usually mean by “common sense” something like the obvious way things are, what we take for granted before anyone starts philosophising. But sometimes what we call common sense is really a set of inherited metaphysical assumptions, assumptions about what is real, what exists and what ultimately explains things, that have become so familiar that we no longer recognise them as assumptions.
As Clarence Irving Lewis noted:
“Experience does not categorise itself. The criteria of interpretation are of the mind: they are imposed upon the given by our active attitudes. … Indeed our categories are almost as much a social product as is language, and in something like the same sense. … That the categories are fundamental in such wise that the social process can neither create nor alter them, is a rationalistic prejudice without foundation.”
The very categories through which we make sense of the world already embody assumptions about what sort of world it is. Someone today might say, quite sincerely, “I don’t believe in metaphysics; I just believe in what can be observed.” Yet this already presupposes answers to rather substantial questions about what counts as real, what sorts of things exist, what observation discloses, whether reality is fundamentally material, whether causes are reducible to regularities, whether explanation terminates in brute fact, and so on.
Consider one particularly familiar assumption, that there is an objective world of matter, quantity, extension and measurable properties, and a subjective world of consciousness, experience and qualitative perception; known to philosophers through the primary-secondary quality distinction. The first seems to be what is really out there; the second, somehow, what the mind contributes.
This feels like common sense, but it too has a history. Its roots are ancient, germinating in Greek philosophy, but the seventeenth century transformed older distinctions between appearance and reality. Galileo’s mathematical conception of nature, Descartes’ distinction between res extensa and res cogitans, Locke’s distinction between primary and secondary qualities, and Newtonian physics all contributed to a picture in which the mathematically describable world of matter increasingly appeared to be the real, objective world, while qualitative experience belonged to the perceiving subject; enacting what Alfred North Whitehead would later term the “bifurcation of nature.”
The success of this scientific abstraction then encouraged people to mistake the abstraction for the concrete reality itself. We are tempted to commit what Whitehead termed the “fallacy of misplaced concreteness.” As he put it:
“The enormous success of the scientific abstractions, yielding on the one hand matter with its simple location in space and time, and on the other hand mind, perceiving, suffering, reasoning, but not interfering, has foisted onto philosophy the task of accepting them as the most concrete rendering of fact. Thereby, modern philosophy has been ruined. It has oscillated in a complex manner between three extremes. There are the dualists, who accept matter and mind as on equal basis, and the two varieties of monists, those who put mind inside matter, and those who put matter inside mind. But this juggling with abstractions can never overcome the inherent confusion introduced by the ascription of misplaced concreteness to the scientific scheme of the seventeenth century.”
By the end of the seventeenth century, the mechanical universe was increasingly being treated not merely as a successful scientific model but as a description of reality itself. Each new triumph of physics seemed to confirm the worldview behind it, while there was comparatively little appetite for examining its metaphysical foundations.
Edwin Arthur Burtt gets to the heart of this transformation:
“How could the world of physical matter be reduced to exact mathematical formulæ by anybody as long as his geometrical concentration was distracted by the supposition that physical nature is full of colours and sounds and feelings and final causes as well as mathematical units and relations? … To get ahead confidently with their revolutionary achievements, they had to attribute absolute reality and independence to these entities in terms of which they were attempting to reduce the world. This once done, all the other features of their cosmology followed as naturally as you please. It has, no doubt, been worth the metaphysical barbarism of a few centuries to possess modern science. … These founders of the philosophy of science were absorbed in the mathematical study of nature. Metaphysics they tended more and more to avoid, so far as they could avoid it; so far as not, it became an instrument for their further mathematical conquest of the world.”
This transformation affected more than the description of nature. It changed what counted as an explanation. The older Scholastic picture had understood nature teleologically, with things not merely having efficient causes but ends towards which they were ordered. In the emerging mechanistic picture, final causes increasingly dropped out of the account. Nature became a system of masses in motion governed by mathematical laws, and explanation came to mean identifying the mechanisms that produced an event rather than asking what it was for.
The medieval theological picture was transformed. God increasingly ceased to function as the ultimate end towards which Creation was ordered and became instead the First Cause, Designer or guarantor of an intelligible cosmic Machine. As mechanistic science advanced, even this role became progressively less necessary. The Machine could increasingly be understood without the Mechanic.
Burtt described what happened to Newton’s metaphysical inheritance particularly well:
“In short, Newton’s cherished theology was rapidly peeling off by all the competent hands that could get at him, and the rest of his metaphysical entities and assumptions, shorn of their religious setting, were left to wander naked and unabashed through the premises of subsequent thought, unchallenged by thorough criticism because supposed as eternally based as the positive scientific conquests of the man who first annexed the boundless firmament to the domain of mathematical mechanics.”
Burtt’s account describes the intellectual transformation. Owen Barfield helps explain how it became a way of experiencing the world itself:
“Geometry, applied to motion, produces the machine. … Our collective representations were born when men began to take the models, whether geometrical or mechanical, literally. The machine is geometry in motion, and the new picture of the heavens as a real machine, where the new theory of inertia (in its early form of ‘impetus’) assumed, for the first time in the history of the world, that bodies can go on moving indefinitely without an animate or psychic ‘mover’. It was soon to be stamped indelibly on men’s imaginations by the circumstance of their being ever more and more surrounded by actual artificial machinery on earth. The whole point of a machine is, that, for as long as it goes on moving, it ‘goes on by itself’ without man’s participation. To the extent therefore that the phenomena are experienced as machine, they are believed to exist independently of man, not to be participated and therefore not to be in the nature of representation. …
“All this is not of course to say that science today conceives of nature as a machine, or even on a mechanical model. It is to say that the ordinary man has been doing just that for long enough to deprive the phenomena of those last representational overtones … which still informed them in the Middle Ages, and to eliminate from them the last traces of original participation. In doing so, he has produced the mechanomorphic collective representations, which constitute the Western world today.”
But the philosophical problems did not disappear. Indeed, removing the theological framework exposed a problem that had previously been partly concealed by it. If mind and world are fundamentally different, and the world exists independently of the mind that knows it, what exactly connects the two? How can an intelligence located within the world acquire trustworthy knowledge of a world supposedly existing outside it?
The problem was already implicit in Descartes. He had begun with res cogitans as the immediate certainty and had required a further argument, involving God, to establish the existence of an external mechanical world. Yet as the modern scientific picture developed, that relationship was gradually reversed. The extended, measurable world became the unquestioned reality, while mind became the problem to be explained.
Bishop Berkeley attacked the very idea of a material world existing independently of perception, while Kant later argued that space and time themselves belong to the intuitive conditions through which we experience a world, rather than simply being properties of things-in-themselves. The problem had shifted. Instead of asking only what the world is made of, philosophy increasingly had to ask what it means for a world to appear to a knower at all.
This is where the history becomes particularly interesting. Wolfgang Smith writes of this:
“It is to be observed that ere long, scientists accepted the res extensa as a gospel truth, while totally rejecting the arguments by which Descartes had sought to bolster that notion. At the hands of the British school, moreover, the res cogitans (which had originally been conceived as an unextended substance) was at first imprisoned within a ventricle of the brain (the so-called Newtonian sensorium), and later eliminated in toto. By a curious reversal of Cartesian logic, the res extensa gained precedence over the res cogitans, or as one might almost say: the conjecture swallowed up the dream.”
The remarkable thing is that a distinction which began as a philosophical problem can become so deeply embedded in our intellectual culture that it ceases to look philosophical at all. The quantitative comes to seem fundamental. The qualitative becomes something occurring inside us. The mathematically describable becomes reality itself, while everything else is increasingly treated as secondary, subjective, or in need of reduction.
None of this means that modern science is wrong, of course. Its unprecedented success is precisely what makes the question interesting. A method can be successful at describing and predicting certain aspects of nature without thereby settling the metaphysical question of what nature ultimately is.
As Whitehead observed:
“Every scientific man in order to preserve his reputation has to say he dislikes metaphysics. What he means is he dislikes having his metaphysics criticized.”
As Burtt reminds us:
“To begin with, there is no escape from metaphysics, that is, from the final implications of any proposition or set of propositions. The only way to avoid becoming a metaphysician is to say nothing.”
And as Owen Barfield had put it:
“You will sometimes hear people say they have no metaphysics. Well, they’re lying. Their metaphysics are implicit in what they take for granted about the world, only they prefer to call it common sense.”
There is no metaphysics-free position. There are only explicit metaphysical commitments and implicit ones. The danger isn’t having a metaphysics, but forgetting that we have one, calling it “common sense.”