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Joel David Hamkins

Joel David Hamkins is a mathematician and philosopher and the John Cardinal O’Hara Professor of Logic at the University of Notre Dame who works on set theory, the philosophy of mathematics and the infinite; he proposed the set-theoretic multiverse view and, with collaborators, created the theory of infinite time Turing machines.

Contents22 sections
Key facts

B.S. in Mathematics from Caltech

Hamkins received a B.S. in mathematics from the California Institute of Technology in May 1988.⁠[1]

He recalls that as a Caltech freshman, taking his first genuine logic course, he learned that logic was an entire field of study and decided it would be his future; the incompleteness theorems and the independence phenomenon fascinated him early on.⁠[2]

PhD in Mathematics from UC Berkeley

Visiting Assistant Professor at UC Berkeley

After his PhD he held a postdoctoral visiting assistant professorship at Berkeley in the 1994–1995 academic year; he had already been offered his position at the City University of New York and deferred its start from 1994 to 1995.⁠[4]

Joins the CUNY College of Staten Island

In 1995 he joined the mathematics faculty of the CUNY College of Staten Island, serving as assistant professor 1995–1998 and associate professor 1999–2002, receiving tenure in 2000 and becoming full professor in 2003.⁠[5]

JSPS Fellow at Kobe University

From January to December 1998 he held a fellowship from the Japan Society for the Promotion of Science at the Graduate School of Kobe University, as part of its logic group, with Philip Welch as his official mentor.⁠[6]

Submits the Infinite Time Turing Machines Paper

On August 21, 1998, he and Andy Lewis submitted “Infinite Time Turing Machines” to arXiv, extending the operation of Turing machines to infinite ordinal time and investigating the resulting supertask theory of computability and decidability on the reals; the paper was noted as forthcoming in the Journal of Symbolic Logic.⁠[7]

Carnegie Mellon, Georgia State and Münster

Submits “The Modal Logic of Forcing” with Benedikt Löwe

On September 27, 2005, he and Benedikt Löwe submitted “The modal logic of forcing” to arXiv, using modal logic to capture the general principles relating forceability and truth in set theory and proving that, if ZFC is consistent, the ZFC-provable principles of forcing are exactly the modal theory S4.2.⁠[9]

The paper later appeared in the Transactions of the American Mathematical Society, volume 360, issue 4 (2008).⁠[1]

Proposes the Set-Theoretic Multiverse

On August 22, 2011, he submitted “The set-theoretic multiverse” to arXiv, introducing and defending the multiverse view that there are many distinct concepts of set, each instantiated in its own set-theoretic universe; he argued that on this view the continuum hypothesis is settled by our extensive knowledge of how it behaves in the multiverse and can no longer be settled in the manner formerly hoped for.⁠[10]

The paper was published in the Review of Symbolic Logic, volume 5 (2012).⁠[3]

Research on Infinite Chess

On February 18, 2013, he and C. D. A. Evans submitted “Transfinite game values in infinite chess” to arXiv, studying the transfinite game values in chess on an infinite board and proving that every countable ordinal arises as the game value of a position in infinite three-dimensional chess.⁠[11]

He has said that while visiting the philosophy department at New York University he posted one of his infinite chess positions as a puzzle on his office door, where graduate students and postdocs gradually added proposed solutions.⁠[2]

Professor of Logic at Oxford

While at Oxford he said that much of his work concerned potentialism in the philosophy of mathematics and that his research often followed a cycle in which philosophical inquiry and mathematical analysis drive each other.⁠[13]

Distinguished Professor at CUNY

In 2020 he was named Distinguished Professor at the CUNY College of Staten Island; he had been on the CUNY Graduate Center’s doctoral faculty in mathematics since 1997, computer science since 2002 and philosophy since 2013.⁠[14]

He was a founding co-organizer of the weekly CUNY Logic Workshop and founded the CUNY Set Theory Seminar.⁠[14]

Publishes Lectures on the Philosophy of Mathematics

MIT Press published his Proof and the Art of Mathematics in 2020 and Lectures on the Philosophy of Mathematics in 2021.⁠[3]

Reviewer Danny Yee noted that the latter is based on lectures for an Oxford honours course and is written mainly for mathematicians, and said Hamkins “writes exceptionally clearly.”⁠[15]

Moves to Notre Dame

In January 2022 he took up a position at the University of Notre Dame, appointed in the Department of Philosophy with an affiliation with the Department of Mathematics; he said he expected to work with students in both philosophy and mathematics.⁠[16]

Writing The Book of Infinity

As of November 2023 he was working on The Book of Infinity and exploring set theory, potentialism and modal model theory with students and faculty at Notre Dame.⁠[17]

Daniel Solow Author’s Award

His Proof and the Art of Mathematics received the Mathematical Association of America’s 2024 Daniel Solow Author’s Award; in his response he said that the book’s theorems are all amenable to elementary proof, making it suited to teaching the craft of proof writing.⁠[18]

Appears on the Lex Fridman Podcast

He appeared on episode 488 of the Lex FridmanLex FridmanLex Fridman is a Soviet-born, US-raised computer scientist and podcast host who works as an MIT research scientist on human-AI interaction and autonomous driving. His Lex Fridman Podcast is known for hours-long conversations with guests including heads of state and technology leaders.Open the full entry Podcast, whose description calls him a mathematician and philosopher specializing in set theory, the foundations of mathematics and the nature of infinity; topics included infinity and paradoxes, Russell’s paradox, Gödel’s incompleteness theorems, the halting problem, the continuum hypothesis, the mathematical multiverse, surreal numbers, P vs NP and infinite chess.⁠[19]

Alternative Fields Medal

In August 2026 he announced that he had been awarded the Alternative Fields Medal in recognition of “Excellence in exposition of mathematics to a popular audience”; he said the citation mentions his books and his nearly 2,000 posts on MathOverflow since 2010, reaching 5.8 million viewers.⁠[20]

The Book of Infinity Is Published

On August 25, 2026, the MIT Press published his 400-page The Book of Infinity; the publisher describes its 25 chapters as moving from classical paradoxes such as Zeno and Hilbert’s hotel to Cantor’s transfinite arithmetic, the continuum hypothesis, surreal numbers and debates about potential versus actual infinity.⁠[21]

As of October 2026: Writing on MathOverflow and Infinitely More

As of October 2026 his MathOverflow reputation stood at 251,569, with 1,982 answers reaching about 6.0 million people.⁠[22]

On his website he states that his MathOverflow contributions have earned the site’s top-rated reputation score.⁠[8]

On his Substack newsletter Infinitely More he serializes The Book of Infinity, A Panorama of Logic and a new book on infinite games, and writes a series of essays on the surreal numbers.⁠[23]

Related Organizations, Websites, and Public Accounts

University of California, Berkeley: Official website: https://www.berkeley.edu/ (opens in a new window)⁠[4]

City University of New York: Official website: https://www.cuny.edu/ (opens in a new window)⁠[5]

University of Oxford: Official website: https://www.ox.ac.uk/ (opens in a new window)⁠[12]

University of Notre Dame: Official website: https://www.nd.edu/ (opens in a new window)⁠[16]

Sources

  1. Joel David Hamkins | People | Department of Mathematics | University of Notre Dame (opens in a new window)
  2. Playing infinite chess - 3:16 (opens in a new window)
  3. Joel David Hamkins (opens in a new window)
  4. University of California at Berkeley, Visiting Assistant Professor, 1994 – 1995 (opens in a new window)
  5. City University of New York, since 1995 (opens in a new window)
  6. Kobe University, JSPS Fellowship, 1998 (opens in a new window)
  7. Infinite Time Turing Machines (opens in a new window)
  8. About | Joel David Hamkins (opens in a new window)
  9. The modal logic of forcing (opens in a new window)
  10. The set-theoretic multiverse (opens in a new window)
  11. Transfinite game values in infinite chess (opens in a new window)
  12. Oxford University, Professor of Logic & Sir Peter Strawson Fellow, University College Oxford (opens in a new window)
  13. Profile: Professor Joel David Hamkins - University College Oxford (Univ) - Univ (opens in a new window)
  14. Joel David Hamkins (opens in a new window)
  15. Lectures on the Philosophy of Mathematics (opens in a new window)
  16. O’Hara Professor of Philosophy and Mathematics, University of Notre Dame (opens in a new window)
  17. Philosophy professor finds questions about mathematics and infinity to be endlessly fascinating (opens in a new window)
  18. Daniel Solow Author’s Award 2024 (opens in a new window)
  19. #488 – Infinity, Paradoxes that Broke Mathematics, Gödel Incompleteness & the Multiverse - Joel David Hamkins | Lex Fridman Podcast (opens in a new window)
  20. Alternative Fields Medal, awarded August 2026 (opens in a new window)
  21. The Book of Infinity by Joel David Hamkins: 9780262054010 | PenguinRandomHouse.com: Books (opens in a new window)
  22. User Joel David Hamkins - MathOverflow (opens in a new window)
  23. About - Infinitely More (opens in a new window)