David Deutsch: at the beginning of infinity, why wrongness is the engine
Key points
Key takeaways from the Modern Wisdom interview with physicist David Deutsch (October 2026):
On knowledge and misunderstanding. Deutsch, in his Popperian view, argues there is only one way to create knowledge — conjecture and error-correction — shared by evolution, science and a child learning language. When communication fails, the communicator, not the listener, has mis-pitched to the listener's problem situation.
Certainty is not a virtue. Every adult has been sure of something that proved wrong, so the feeling of certainty is no guide to the truth, and neither is authority: a person can be ignorant or malevolent and still be right on a particular point, so ideas must be judged by the quality of their error-correction, not the standing of their source.
Optimism as method, not mood. Deutsch's optimism is not cheerfulness but the stance that every failure is a solvable problem. "We are all at the beginning of infinity" — everyone is at the same early point in an infinite growth of knowledge, which is why holding oneself up as an authority is a mistake.
Against belief. He goes further and argues belief itself is a corrupt category inherited from Platonism and Christianity; what matters is reason and error-correction, and disbelief cannot be made immoral because it cannot be chosen by an act of will.
Weaponised uncertainty. The internet fuses production of ideas with publication, so conjectures are attacked as errors before they can develop. Deutsch no longer floats ideas on X, and recommends labelling speculation as question or conjecture — or writing it as fiction, as he has done with his book on the Fermi problem, set in a fictional universe to invite criticism.
On AI risk. Asked about researchers leaving Anthropic over existential-risk fears, Deutsch argues AGI will not pose a great threat to humans — a markedly calmer line than the recent superintelligence scares, consistent with his broader view that knowledge grows through error-correction rather than catastrophe.
Science and the joy of being wrong. He believes the sensation of being baffled — a state of collision where something looks true and impossible at once — is what attracts him to research; "a small fact can destroy a large reputation", so he prefers forming testable theories over trusting reputations.
Read more: Modern Wisdom — YouTube
