The Great Conversation:
Physics
By Gabriel Blanchard
Under the seemingly-unassuming name "Physics Dept.," colleges all over the country house scholars who would unveil what may be the almost-literal artwork of God.
Physics holds a rather unusual place in the history not just of thought, but of education. Many disciplines which used to be one have been vastly whittled down or subdivided, usually with a corresponding loss of prestige: the word logic, for instance, used to be almost equivalent to what we now describe as philosophy (or at least to parts of it*), but now covers a far more restricted field, limited almost entirely to analyzing arguments for structural validity. Other disciplines have been so radically altered, whether in their basic content or their procedural methods, that they are scarcely recognizable as the same object of study (which has interesting and sometimes unexpected implications for the classical renewal movement). Even in a field as seemingly immune to change as mathematics, if an ancient geometer like Archimedes or Ptolemy were shown a modern calculus problem, he could easily be pardoned for thinking at first glance that he had been presented with a magical diagram! Physics has suffered both these fates, and yet it remains not only an illustrious science,* but one of the most influential upon the other sciences. The borders of its domain have changed, and now cover much of the territory astronomy once ruled, but its repute has if anything only increased since antiquity.
This is in part thanks simply to the position physics occupies on the STEM spectrum, ranging from least to most abstract. The fields we call the sciences today, and engineering and technology accordingly, are those which can be quantified, i.e. understood in terms of numerical values and relationships.† The highest level of numerical abstraction possible is, of course, numbers themselves, and thus mathematics as a discipline.
Let us then postulate a physical world—any physical world, whether it’s got organic life and minds like ours does, or just undifferentiated matter and nothing else. Physics is the discipline that studies this level of existence: the behavior of matter and energy in space and time, simply as such. It is only “on those conditions,” so to speak, that chemical formation, reaction, and decay all take place, thus giving us entities like stars; we can thus say that chemistry is conditioned by physics. The particular planetary features of the earth and of organic life, in turn, exist only on the terms of chemistry (and break down promptly if these terms are defied too boldly!), so that fields such as geology, geography, and biology are all conditioned by chemistry, and through it by physics. This naturally applies all the way down the “assembly line” of material reality. This positions physics as in some sense the master discipline among the sciences—the one that contains or governs all the rest.
All science is either physics or stamp collecting.
The history of physics is, of course, more complex than this. The name of the discipline comes from Aristotle’s Physics,‡ though this was concerned only with those things—living or not—that, like us, are to be found in or on or not very far above the earth. Based on what even then was thousands of years of observation, it seemed plain that the heavens did not change except in regular cycles, if that even counted as change. But here on earth, and clearly well upwards into the atmosphere, the stuff of which everything was made was subject to ceaseless change. Physics was thus almost “the study of the terrestrial,” the changeful world beneath the Moon, the one place where things passed into and out of being continually.
A lot of things about physics changed over the course of the seventeenth and eighteenth centuries, and this ancient idea of nature broke down. Sir Isaac Newton was the architect of the next: his 1687 Principia laid out his famous three laws of motion, the first version of what would come to be known as classical mechanics. Some notable features of classical mechanics are that, in it, the movement of every material body is absolutely predictable in principle, whether we are looking forwards or backwards in time: no motion is random, and the system’s laws cannot be violated. But the information available for physicists to study was still improving. In 1859, French astronomer Urbain le Verrier (who had already, based on irregularities in the orbit of Uranus, predicted the location of the as-yet undiscovered planet Neptune to an error margin of a single degree!) determined that there was something strange about the orbit of Mercury too. It was ultimately determined that Newtonian mechanics also work properly only within certain limits—i.e., they are not true laws but approximations.
Albert Einstein determined that Newton’s laws fail when dealing with objects on the galactic scale, or objects whose velocity (like that of an unladen swallow) is a considerable fraction of the speed of light. Indeed, it was to resolve these problems that he proposed his theories of relativity: general relativity applies to space-time as a whole, while special relativity describes our “local” interactions with, or rather in, space-time. This is where we get the idea of gravity as “curvature in space-time” caused by mass, often depicted as billiard balls on a large rubber sheet. It is also from Einstein that we first got the theory of the existence of black holes, which have since been proven to exist but whose strange properties continue in some respects to baffle modern science.
However, only shortly after Einstein had corrected the flaws in Newton, something else happened: a Danish scientist named Niels Bohr determined that Newton’s laws fail when dealing with subjects on the atomic scale. Indeed, it was to resolve this problem that he proposed his theory of quantum mechanics; and, if you have seen or read anything about modern physics in the last decade or so, especially anything that prominently featured words and phrases like string theory or eleven dimensions or Heisenberg uncertainty principle or the Calabi-Yau manifold (that old chestnut), you may know already where this is going! Obviously, quantum mechanics very neatly explain the atomic-level problems Bohr and his colleagues had been working on, and furthermore have been formidably verified by experiment, just like relativity has; inevitably, the two systems don’t make sense together and no one has yet been able to construct an overarching theory that subsumes the two. The possibility of creating a unified field theory—a theory that is to physics in general what physics is to science in general—remains one of the tantalizing unresolved inquiries of this discipline.
Suggested reading:
Aristotle, On the Heavens
Nicomachus of Gerasa, Introduction to Arithmetic
Francis Bacon, Novum Organum
Johannes Kepler, A New Astronomy
Albert Einstein, Foundations of the Theory of General Relativity
Werner Heisenberg, The Physical Principles of the Quantum Theory
C. S. Lewis, The Discarded Image
Stephen Hawking, A Brief History of Time
*Specifically, logic used to indicate approximately those divisions of philosophy known as ontology, or the study of being and becoming, and epistemology, or the study of knowledge, learning, and inference; what we now call “logic” was referred to by our ancestors as dialectic. Similarly, science used to be just a synonym for knowledge: it came thus to mean “field, subject,” and thence to the modern meaning.
†It might be better to say, the sciences study the quantifiable aspect of things. Suppose we are measuring the average height of Portuguese ironmongers, as one does. We do not exhaust the truth of their humanity (or even the truth about their human bodies) by doing so. But this is because we are only asking one highly-specified question; it’s not that there is nothing to be known about Portuguese ironmongers except their average height.
‡The title, τὰ φυσικὴ [ta phusikē], literally means “on things that come to be.” The feel of this title is tougher to translate, because the contrast Aristotle was drawing was between things that change and things that don’t,
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Currently employed as CLT’s editor at large, Gabriel Blanchard is a proud uncle of seven nephews. He has a bachelor’s in Classics from the University of Maryland, College Park, and lives in Baltimore.
Be sure to check out some of our other installments in the history of Western thought; we have introductions to ideas such as animal life, chance, the nature and rules of definition, liberty, time, truth, the human will, and many more. We also have a podcast, Anchored, hosted by our founder, as well as a seminar series and a YouTube channel. Thank you for reading the CLT Journal, and have an excellent day.
Published on 13th July, 2023.