The Physics of Philosophy

A Tale of Misdirected Unrequited Love

Philosophy fawns over physics, praises it, admires it, offers to carry its books to and from school. The logical positivists deemed it the arbiter of meaning. And even after the dust settled and sanity was restored, the demand that philosophy be naturalized – modeled on the natural sciences (and on physics in particular) – remained.

Since then philosophy’s infatuation has only grown more desperate. No longer the arbiter of meaning, philosophy has promoted physics to the arbiter of truth. And, even more importantly, to the arbiter of respectability. “Go ahead and dazzle us with your theories,” philosophy tells its people, “but woe be unto them (and you) if they run afoul of the world as physics understands it.” 

The adoration and deference have persisted for well over a century and are by now instinctive. Physics encroaches on philosophy’s turf without fear, proposing theories of space, time, reality, and the origins of everything, and philosophers mostly cheer it on. Make no mistake: they could resist. They could (rightly) accuse physics of exceeding its bounds, venturing into areas of conceptual uncertainty, paradox, and speculation that its methods and equations are ill-equipped to handle. But most wouldn’t dare. And, if they did, other philosophers would be the first to scoff.  

In the annals of interdisciplinary capitulation there is perhaps no entry more abject than philosophy’s wholesale embrace of physicalism – the view that, at bottom, everything is physical – that if there is such a thing as consciousness, will, and meaning, they must be explicable in physical terms. And who might supply those terms but physics: the arbiter of the physical? And so philosophy’s central mission – to uncover reality’s fundamental nature – to discover that out of which everything is made – has been outsourced to a rival.

Perhaps I’m just bitter. But the bitterest pill of all is that philosophy’s capitulation may not even be entirely misguided. Physics, despite the constant praise and adulation, is actually doing something right. There’s no denying that it’s figured something out. And it has something to teach the rest of us.

But what?

The Secret of Physics’s Success

Physics is many things: formalism, reduction, experiment, observation, modeling, parsimony, conceptual specialization, the dogged pursuit of fundamentality, and, when in doubt, trusting the math. But those qualities are not unique to physics; they’re in every natural and social science save the pursuit of fundamentality. And philosophy has been pursuing fundamentality even longer than it’s been pursuing physics. And if these qualities aren’t unique to physics, then they can’t explain its unique success.

So what does?

Physics is in the business of explanation. So is philosophy and all the natural and social sciences; they’re all trying to explain something. And so, if physics is offering better explanations than philosophy – and better than anyone else – it stands to reason that that would be because it’s discovered something about explanation itself. Physics may have figured out a form of explanation that’s both illuminating and that separates it from the herd.

Hierarchy vs. Opposition

If you study philosophy you’ll soon enough encounter the idea that you can’t really explain anything. You can explain A in terms of B, B in terms of C, and so on. But eventually you’ll run out of reasons (usually faster than you think). And so your entire belief system is built on sand.

That hierarchical model – A is explained by B, B by C, C by D, and so on – is intuitive and frequently deployed, its ultimate futility notwithstanding. Why did he slip on the sidewalk? Because the ground was wet. Why was the ground wet? Because it rained. Why did it rain? Because the water vapor in the atmosphere condensed into droplets. Why did the water vapor condense into droplets? And so on.  

And the hierarchical model is popular throughout academia. A philosopher, for instance, might explain how you’re the same person you were yesterday in terms of psychological continuity, psychological continuity in terms of memories, and memories in terms of neural patterns. A historian might explain the fall of Rome as a series of discrete but cascading events.    

And explanation in physics looks hierarchical. Compounds are explained in terms of molecules, molecules in terms of atoms, atoms in terms of subatomic particles (protons, neutrons, electrons), subatomic particles in terms of quarks, and quarks in terms of quantum fields.

But look closer. Because the dominant explanatory model in physics is not hierarchical but oppositional. It’s not “A is explained by B” but “A is explained by the opposition between B and C.” Atoms may be explained in terms of subatomic particles, but an atom’s stability is explained by the opposition between attractive and repulsive forces. That’s how physics explains stability in general, whether atomic, cosmological, or otherwise. Stability, physics understands, is just forces in opposition.

Forces in Opposition

Why does the earth stay in its orbit? It’s two forces – gravity and angular momentum – acting in opposition. One draws the Earth inward, the other pushes it outward, and a steady orbit results.

How do airplanes fly? It’s forces in opposition: lift vs. gravity, thrust vs. drag, lower air pressure above the wing opposed by higher pressure below it.  

How does walking work? It’s opposition at multiple levels. Gravity pulls the body down and a ground reaction force pushes it up. Forward propulsion opposes friction. Forward momentum opposes vertical instability (that’s why it’s hard to walk extremely slow). On a muscular level, there’s opposition between agonist and antagonist forces (e.g. quads vs. hamstrings). At a neurological level, there’s opposition between excitatory and inhibitory signals.

The idea of opposition is baked into Newtonian mechanics: every action has an equal and opposite reaction. You push against a wall and it pushes against you.  

(As a kid, I found Newton’s third law perplexing. If every action has an equal and opposite reaction, I wondered, then how does anything move? If I push on a wall and it pushes back against me with an equal and opposite force, then how could my hand ever go through it? I’ve heard several explanations – that the opposing force doesn’t necessarily come from the same object or that it just has to manifest somewhere – but I think a better explanation is that motion requires every action to have an equal and opposite reaction; motion is the product of opposition. Otherwise something would have to come from nothing.)

And the oppositional model survives the 20^th century. There’s matter and anti-matter, particles and anti-particles, symmetry, conservation laws, uncertainty and complementarity principles. Spacetime itself can be understood as an amalgam of opposing forces (space and time); Einsteinian physics tells us that as an object's speed through space increases, its passage through time slows. Space and time preserve the speed of light’s constancy through their mutual opposition. And though it’s not a standard interpretation, spacetime’s curvature could be explained as arising from the opposition between the tendency of mass-energy to occupy spacetime and spacetime’s resistance to being de-formed.

And so we hit a wild conclusion: physics may be head and shoulders above the rest because it’s solved the paradox of explanation. It may have discovered a way to dump the hierarchical model and to make explanations mutually reinforcing without collapsing into circularity. No wonder it’s kicking our ass.

The Oppositional Model

Physics is not entirely alone in having embraced the oppositional model. Economics – the most successful and respected of the social sciences – uses it as well. Economic explanation typically takes the form of opposing forces falling in and out of equilibria. Price is just supply and demand in opposition. Interest rates are determined by the ratio of savings to investment. Exchange rates fluctuate on the basis of the demand for currency as opposed by its supply.  

You’ll find the oppositional model in parts of biology as well. An organism’s survival, for instance, is explained in terms of homeostasis (a fancy word for processes in opposition). Ecological explanation typically takes this form as well.  

But in many areas the hierarchical model reigns supreme. Illness, mental or physical, is typically explained in terms of a blockage, dearth, excess, rupture, or decay and not in terms of opposition. The germ theory of disease, for instance, posits particular pathogens as causes. Mental illnesses are sometimes explained by a dearth or excess of a particular neurotransmitter. Such monocausal, hierarchical explanations aren’t necessarily wrong. They could even be quite useful. But they are necessarily incomplete. At best they’re telling half the story. Illness, like life, is a product of opposing forces; that’s why, after you get sick, you (usually) eventually get better. There’s the germ that invades and the body that fails to counteract it. Two people may be exposed to the same pathogen but only one gets sick. Often you get better just by believing that the medicine is on its way.    

And the hierarchical model dominates philosophy, partly due to the misconception that that’s what made physics so successful.  

The Physics of Philosophy

The philosophy of physics applies philosophy to physics: it takes the concepts and theories that physics produces and tries to jam them into a hierarchical model. The physics of philosophy applies physics to philosophy: it takes the concepts and theories that philosophy produces and coaxes them into an oppositional model.  

To do the physics of philosophy, all you have to do is start your philosophizing with the supposition that your subject matter – consciousness, agency, personal identity, knowledge, wellbeing, whatever – is best explained not in terms of one thing but two or more in opposition.

I’ll give detailed examples in later posts. But below are some suggestions just by way of illustration.

Knowledge may seem hierarchical, to be explained in terms of truth, justification, warrant, and belief. But counterexamples abound. And so consider an oppositional alternative. Instead of seeing knowledge as a set of discrete attitudes and states, it could be seen as a product of understanding at different levels of granularity – a fit between reductionism and holism – a harmony between your grasp of the whole and your grasp of its parts. That could even account for the intuition that knowing something requires having both an internal representation of it and being able to explain it to others.

Wellbeing obviously consists in a kind of internal balance or harmony, as many ancients claimed. It’s not just an accumulation of discrete bundles of pleasure, desire-fulfillment, achievement, etc., or some combination thereof.  

Personal identity needn’t be explained in terms of beliefs, desires, memories, or bodily continuity. Rather, it could be a function of internal opposition: it’s your inner conflicts that define you. Like the earth’s orbit, you’re a product of oppositional forces: your consciousness pulls you one way and your unconsciousness pushes in another. Identity is a kind of stability and stability is forces in opposition.  

Consciousness remains a mystery, but maybe not for long if we abandon hierarchy for opposition. On an oppositional model, consciousness could be understood as arising from a tension between a self and its self-representation: from the duality created by a self’s experiments in self-awareness. The self wants to understand itself, and so it creates a representation of itself within itself.

My dear philosophers. I cannot vouch for any of these analyses. They’re just suggestive. They may or may not bear fruit. Nevertheless, our predicament is clear. The hierarchical model has forsaken us. We need another option, and physics lights the way.

If we must adore her, let’s at least adore her for the right reasons.