When I’m in a provocative mood, I argue that it’s tougher to make it in science writing than in science, hence science writers are, on average, smarter than scientists. As an (admittedly single) data point, I might cite Jim Holt. As he demonstrates in his 2012 bestseller Why Does the World Exist? (which I loved) and new essay collection When Einstein Walked with Gödel (see reviews by The New York Times and physicist Peter Woit), Holt writes with pizzazz about scientific, mathematical and philosophical concepts that cow lesser minds. No mere explicator, he is intellectual aesthete, a connoisseur of concepts. He holds ideas and their inventors up to the light for our delectation, pointing out features that we might have missed. In the preface of his new book he says his goal is to “enlighten the newcomer while providing a novel twist that will please the expert. And never to bore.” A high bar, over which Holt soars. Irony is his preferred rhetorical mode. He seems to view earnest conviction with distaste. In the following Q&A I hope to pin him down on matters of import. --John Horgan

Horgan: Are you as smart as you think you are?

Holt: Almost certainly not. There is abundant evidence that people tend to overrate their own abilities, including their intelligence, and I am unlikely to be exceptionally free of such "positive illusions." An accurate assessment of my intelligence was furnished by the mathematician Bob Stong, (of "Hattori-Stong theorem" fame) during my oral exam for a master's degree in mathematics. After I had fumbled a couple of easy questions about group theory (e.g. How many groups are there of order 15?), Stong announced, "Mr. Holt, you do not deserve an M.A. in mathematics. You do not deserve a B.A. in mathematics. You deserve a B.A. in sociology."

Horgan: And modest too! As far as I can tell you’re a fox, you don’t have a big idea. Or do you?

Holt: I do in fact steer by One Big Idea, which makes me a hedgehog rather than a fox. It is this: the part of reality that we can make meaningful claims about is limited by our experience and observation. This is a Big Idea that tends to deflate other Big Ideas.

Horgan: I like it. What’s the point of philosophy if it never really answers any questions?

Holt: I don't accept your premise. John Rawls answered the question, "What is a just society?" with his two basic principles of justice, derived from an analysis of fairness. This was an enormously important advance. Saul Kripke answered the question, "What are the truth conditions for claims about necessity and possibility?" with his semantics for modal logic. Edmund Gettier answered the question, "Does knowledge equal justified true belief?" in the negative, by coming up with "Gettier examples." Even when philosophy can't answer questions decisively, it can clarify them by making needed distinctions and bringing out hidden assumptions--an intellectual activity that often points the way to new and better questions.

Horgan: Why do many great philosophers seem nuts? If you devote yourself to studying life, shouldn’t you be competent at living?

Holt: What are you talking about? Nearly all the greatest philosophers in history have been eminently sane, and even practically talented. Many led exemplary lives, and were downright lovable. (Socrates, Spinoza, and Hume come to mind.) There was hereditary madness in Bertrand Russell's family, but he escaped it and devoted himself first to logic and then to social justice. Wittgenstein had a fraught life, but he did not commit suicide like three of his non-philosopher brothers, and he was adored and emulated by his disciples. The only case I'll concede to you is Gottlob Frege, who was anti-Semitic, which I consider to be a form of mental illness.

A propos, the "nuts" that I write about tend to be mathematicians--Cantor, who created the theory of infinity and died in an asylum, Gödel, who starved himself to death out of a paranoiac fear that there was a universal plot afoot to poison him, Grothendieck, who ended his days as a devil-obsessed recluse in the Pyrenées. I'll spare you the cant about how their mental problems came from escaping Plato's cave and being blinded by the Sun of transcendent mathematical perfection.

Horgan: Yeah, mathematicians do seem nuttier. Of all the great thinkers you’ve written about, is there anyone you would rather NOT have met?

Holt: Benoit Mandelbrot, who from what I hear was unpleasantly and insecurely egomaniacal. And perhaps it's just as well that I never met the awesome Alexandre Grothendieck, because he did not suffer fools gladly.

Horgan: Mandelbrot is an excellent choice. Are you as sick of string theory as I am?

Holt: I’m sick of the "landscape" and the "multiverse" and the "anthropic principle" and the fact that people keep talking about string theory as though it's an actual physical theory with equations and everything as opposed to a bunch of arguments that such a theory might exist. But I'm not sick of the mathematical side: of Calabi-Yau spaces and conformal field theory and the role of string-theoretic ideas in the Langlands Program--the sort of stuff that won Ed Witten a Fields medal in mathematics. I find all that very exciting, even if it's way over my head. (I rely on the mathematician Edward Frenkel to explain it to me.)

Horgan: Will quantum mechanics ever make sense?

Holt: To the disgust of my good friends David Albert and Tim Maudlin, I tend to take an instrumentalist view of science in general and quantum mechanics in particular, so I am not all that vexed by the “measurement problem.” And it is quite possible that quantum mechanics will eventually be superseded by a nonlinear theory (as Roger Penrose and Steven Weinberg have supposed), which would make the “Schrödinger's cat” problem go away. The appearance of nonlocality--EPR, Bell, and so on--is troubling, but I think a better analysis of time and “advanced action” might eliminate the tension between quantum mechanics and special relativity.

Horgan: Ed Witten has said that consciousness is a harder problem than why there is something rather than nothing. What do you think?

Holt: I see consciousness and why-something-not-nothing as two facets of a single mystery: What is reality? Although the structure of reality is mathematical, the “stuff” of reality is consciousness. In Platonic terms, reality consists of phenomena (conscious appearances) imitating mathematical Forms. If that sounds daft, try to imagine a world devoid of consciousness--a world “as it is in itself,” one uncontaminated by sentience. All you end up with is an abstract mathematical structure. What sense does it make to say that this structure has an existence that is robustly physical, as opposed to merely mathematical? So the problem of existence is inseparable from the problem of consciousness.

Horgan: Yeah, like Deepak Chopra says. So who is your favorite philosopher and why? Is Wittgenstein overrated?

Holt: My favorite philosopher of recent times is Hilary Putnam, who taught at Harvard and who died in 2016 at the age of 89. Though I never met Putnam, I read his collected papers over and over again for their technical virtuosity, stunning inventiveness, clarity, and wit. A couple of generations of philosophers lived off the fecundity of Putnam's mind--and were perplexed by his willingness to change it. After helping to solve Hilbert's tenth problem, Putnam invented functionalism in the philosophy of mind, and then renounced it; invented the “Are we brains in a vat?” argument against skepticism; invented the “model-theoretic argument” against realism and then sort of renounced it; and delivered himself of profound observations on Hegel, American pragmatism, the philosophy of mathematics and science, the inseparability of fact and value, and Wittgenstein.

On Wittgenstein: I think (and so did Putnam) that Wittgenstein's philosophy of language and mind are of the very highest importance. But you would be hard pressed to find many younger philosophers today who agree. At the moment, Wittgenstein is rather badly underrated, not overrated. Which means that philosophers are repeating a lot of the mistakes that were made before Wittgenstein came along.

Horgan: If philosophers really learned from their mistakes, they’d probably quit philosophy. Does Gödel’s incompleteness theorem mean that our knowledge will always be incomplete, or is that as dumb as saying that relativity means that everything is relative?

Holt: I don't think Gödel's incompleteness theorems have that implication. [Horgan: Note that Holt just gracefully informed me that Gödel's "theorem" actually consists of two theorems.] Sentences in number theory that are undecidable in the Gödel sense do not really have determinate truth values; they are neither true or false. (To think that they do have determinate truth values you have to believe that we somehow have access to the “intended model” of arithmetic, which exists in Platonic heaven.) The same applies, I think, to the continuum hypothesis in set theory. Mathematicians don't worry much about Gödel. But many of them do think that mathematical knowledge is indefinitely extendable, up a never-ending ladder of “avatars,” and that therefore it will always fall short of completeness.

A more interesting question about the potential completeness of our knowledge is whether physicists will discover a Final Theory. There was optimism about that 25 years ago, when Steven Weinberg wrote Dreams of a Final Theory, but it has largely faded since then. Now a lot of younger physicists and philosophers of physics seem to believe that the best we can hope for is a never-ending series of “effective theories” valid for higher and higher energies--not dissimilar to the picture of mathematics.

Horgan: Do you believe in moral progress? Are things getting better and better, as Steven Pinker keeps assuring us?

Holt: The historical data seem to show a Pinkerish trend toward moral progress over the last couple of millennia--that's the signal. But then there's the increasing magnitude of moral catastrophes, owing both to technology and to larger forms of social organization--that's the noise. (Or have I got the signal and noise reversed?) Looking into the near future, I'm reasonably confidant that current barbarous practices like the punitive incarceration of humans and the abuse of non-human animals in factory farming will be eliminated. But I'm not willing to extrapolate the arc of moral improvement into the very far future, as some lotus-eating visionaries do. There's an abstract quasi-evolutionary argument that moral progress will go on forever, based on the observation that, in computer simulations of iterated prisoner's-dilemma games, the cooperating entities eventually prevail over the cheating entities. So, it is argued, our descendants in the very distant future will be extremely nice to one another. But I don't think we'll have any descendants in the very distant future. About 50 billion humans have come into existence already since the appearance of our species. How many more of us will there be? By the Copernican principle--which says that we humans who exist right now are unlikely to be "special" in the sense of being among the very first or the very last of all humans who will ever exist--we can say with 95 percent certainty that there will be no more than 2 trillion of us to come. Assuming that the population of the earth stabilizes at about 10 billion, that means the human species will be extinguished within about 20 millennia, or even faster if we expand our generational numbers by taking over other planets. And, if I had to guess, I'd say that our probable extinction will be self-inflicted rather than the result of a cosmic accident. In other words, it will be, collectively speaking, our own fault. That's a grave moral failing.

Horgan: Why does Jim Holt exist?

Holt: My distinctive trait is that I’m a dilettante who is always trying to learn something new, and learn it well enough that I can explain it clearly to others. My parents took no interest in my education. No interest at all. I went to a lousy public high school, where I took study hall and driver’s ed. I wasted my undergraduate days in inane courses like religious studies and organic chemistry. It was only near the end of my education that I discovered what I truly loved: mathematics and philosophy. I've been playing catch-up ever since--which gets harder and harder, since I no longer have the brain plasticity to absorb cobordism or Yang-Mills theory. So I'm just a dilettante journalist who hangs out with philosophers and physicists. That's my essence. And I blame that on my parents. Their neglect made me what I am today. They're dead, and I hate them for it. But it's a good life.

Horgan: Jim Holt in driver’s ed, fun to envision. So what’s your utopia?

Holt: My utopia is a society that consists in its entirety of Tim and Vishnya Maudlin, David Albert, Jenann Ismael, Shelly Goldstein, Barry Loewer, Carlo Rovelli, Hartry Field, Trevor Teitel, and me, all arguing eternally about gauge theory while beautiful girls and comely boys peel grapes for us.

Further Reading:

What Is Philosophy's Point? Part I

Science Will Never Explain Why There's Something Rather Than Nothing

Was Wittgenstein a Mystic?

How Physics Lost Its Fizz

See Q&As with Scott AaronsonDavid DeutschGeorge EllisMarcelo Gleiser, Sabine HossenfelderStuart KauffmanChristof KochGarrett LisiPriyamvada NatarajanMartin Rees, Carlo RovelliRupert Sheldrake, Lee Smolin, Sheldon Solomon, Paul Steinhardt, Tyler VolkSteven Weinberg, Edward Witten, Peter Woit and Stephen Wolfram

See also my 2008 Bloggingheads.tv interview with Holt.