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"Not quite true" is irrelevant. An answer never need be fully true, and that is impossible. It only needs to be certain enough to accept a particular fact or take a particular action, and that's a far lower bar, contingent on the greatest information accessible in the moment, not any hypothetical ultimate. Knowledge is always and only justified belief.

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I think Solow means "not quite true" in the sense of simplification or approximation. But the simplifications in his case are in service of a search for (less than ultimate) truth. He was not quite a pragmatist in the sense that you lay out, although he would have smiled at your "always and only" because it's so close to Milton Friedman's "Inflation is always and everywhere a monetary phenomenon."

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More seriously, I think everyone being clear about their unprovable assumptions is the most important thing in social debate. That's the only way to know what kind of discussion you're having. Sometimes you're in a discussion like (a good faith) one about abortion. Some people just believe morally that an early fetus had similar moral status to a free ranging person. Others don't. Fundamentally that's not something you can reason or debate your way out of.

But we often aren't clear about our assumptions. The macro example the post starts with is a good one. Conservative 20th century economic "theory" was always a con. It started with the assumption that plutocracy with near absolute freedom for plutocrats was the ultimate good achievable by society. But it's practitioners weren't idiots so hid that and pretended their base assumptions were made up equations and that they were physicists simply uncovering the truth that crushing plutocracy is best.

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Matt: thanks for the comment.

You make two points. The first is very much in sync with the WoC "ethos" (Shadi's term) and I have no objection to this assumption-exposing, clarity-seeking agenda. My point was that "first principles" is the wrong term for these non-negotiable, dogmatic core beliefs, and I pointed to a tradition where they represented a different, more provisional kind of assumption.

To speak to your second point I would need to know what you include in "conservative 20th centrury economic theory." If you are speaking about the Mises-Hayek libertarian laissez-faire tradition (certainly not the older, Smithian laissez faire tradition!) I would agree that it contained a not-always-explicit make-the-world-safe-for-plutocrats component, but I would add that it's the only school of economics to be based upon explicitly dogmatic, claimed-to-be-self-evident, non-negotiable assumptions. If you're making a broader point about economics or economists, then i think you are off base. My next-favorite Solow quote: "Economics is not the physics of society."

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Yes I'm talking about Mises-Hayek and their acolytes. I know within the economics profession itself mathy (as in truthy) plutocratic ideology as intellectual contribution has diminished. But the story isn't over. Mankiw's book serving as the default intro to econ for an entire generation of students rivals the work of the 20th century charlatan founders. That will have negative effects lasting another 30+ years at least!

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To me, economics is not a science based on the laws of physics, chemistry, or biology. The first is based on the laws of the universe, the second on the laws of the universe, the second of the laws of the universe and physics, and the third on the first three sets of laws. Economics is based on assumptions of human behavior and its “laws” do not have a mechanistic explanation. For example, evolution results from “selection” of varieties of genes in the process of reproduction. Genes are selected for or against in the contest of the environment in which a species is reproducing. The environment does vary, as climate change and global warming clearly demonstrate (and also such things as the wars we are seeing today). The second laws of thermodynamics correctly predicts that entropy increases in closed systems. Life forms are semi-closed systems and thus have a 100% probability of ceasing to be organized enough to continue to exist, entity by entity. I.e., we all die, as predicted by the laws of physics and chemistry. As Kurt Vonnegut noted about human behavior, “so it goes,” That, unfortunately, does seem to be almost a law consistent with entropy.

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You're circling around another Solow quote, "economics is not the physics of society." It's "laws" are only statistically true. But it has the same need as physics to choose its axioms carefully.

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I have applied the idea of first principles to politics and found two such principles, on which I built a scientific theory to solve political problems through what i call democracy engineering. If youre interested to write about it, contact me at troydavis@post.harvard.edu

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Absolutely! I respond by email.

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In what aspect of Einstein’s theory were there any assumptions that were not true? A theory in physics is a detailed explanation of why things are as they are and that allows for accurate predictions to be made. If any prediction is found to not be true than there is something wrong with the theory and it needs to be modified. For over 100 years Einstein’s theory has been tested over and over and not a single prediction has failed the test. This week the theory’s prediction that large gravitational bodies “bend” light will be tested again. And the total solar eclipse will with almost 100% certainty be confirmed again. Newton’s theory of gravitation is not based on any incorrect assumptions. It is mathematically accurate, as is Einstein’s theory. Mathematics is the universal language of science and its theories. A theory in science is not a guess. Darwin’s theory of natural selection was not based on inaccurate guesses. It was based on factual observations. What it lacked at the time was the explanation for the mechanism of natural selection: what was the cause of the differences in traits and how were those differences stored and passed on? Today we know that DNA in genes can change (mutate) leading to changes in traits that may be selected for or against, i.e., increasing or decreasing the likelihood of a gene being passed on. Nothing in Darwin’s theory was based on a falsehood. An incomplete explanation yes, but nothing in the theory needed to be corrected, just expanded. The laws of the universe, such as the laws of gravitation or thermodynamics, etc., are immutable. Human laws are not. That’s why human laws lack the 100% predictably of settled scientific theories.

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Thanks for the comment.

I can't speak in detail to Einstein, but Newton's theories certainly contained simplifying assumptions, and the resulting small predictive errors, put scientists to work for centuries in an attempt to account for them. The assumptions [which bracketed the effects of the planets on each other, etc.] made the theory both possible and fertile. That the spirit of Solow's provocative -- but also humorous -- opening statement; scientific theories are open-ended and subject to improvement because their setup makes them, in some sense, approximations. Darwin's made one big simplifying assumption, so big it's almost invisible, that evolution is a biological process, based on traits in individuals, but ever since Darwin scientists (especially social scientists) have asked whether selection could be group-based (today's "cultural evolution" researchers believe so), and it's a hot debate.

Galileo, though he was ignorant of algebra and statistics, asserted that mathematics is the "language of nature," and most scientists since have shared that assumption/assertion and have given it a deterministic spin -- to the extent that Einstein could not accept some of the non-deterministic implications of quantum theory, etc. Today, we have Stephen Wolfram -- a crank, perhaps, but an interesting one, suggesting that nature is a discrete and "computational" process rather than the law-bound mathematics-speaking entity described by Galileo. so, in the fields you describe I see lots of important, facilitative, fertile, but perhaps limiting assumptions.

Solow's "not quite true" was a joke at Milton Friedman's expense; yes, some of our assumptions may be unprovable, but we had better think our crucial assumptions make sense as statements about the world and are not just chosen to facilitate a result. Newton's assumption allowed him to focus on the main effect, which he had correctly identified, and what Solow proposes is completely in that spirit.

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I like the way you describe Aristotle's approach here. He does seem to hold things a bit loosely. I never get the sense that he's system-building in a way that he wouldn't be willing to revise based on new ideas or new arguments.

How tightly or how loosely we hold to those basic assumptions is the real nut of it. And I wonder how much it comes down to disposition. I was raised in a religious community that taught a lot about "worldviews." On the one hand, it was a helpful framework for seeing the connections between philosophical foundations and their implications. But at its worst, as I see it now, it became a kind of irrational fideist or existentialist position. If all our positions are reducible to assumptions, and we have different assumptions which are simply incorrigible, then there's no conversation to be had. Neither can convince the other of anything. You either have my assumptions or you don't. The result of this worldview absolutism is that "they" cannot be reasoned with.

Hold assumptions loosely like Aristotle and there's space for liberalism, democracy, debate, learning, peer review, experiment, a marketplace of ideas. Hold those assumptions tightly and it comes down to who controls which institutions from which they can promote their worldview as propaganda. (It's either "our" propaganda or "their" propaganda.)

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In the parlance of our times I'd say first principles is code for narcissism in search of a path towards mass rent extraction. Maybe... 23% joking 😁

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