Skip to main content

Pragmatic Platonism

Mathematics and the Infinite

  • Chapter
  • First Online:
Hilary Putnam on Logic and Mathematics

Part of the book series: Outstanding Contributions to Logic ((OCTR,volume 9))

  • 685 Accesses

Abstract

It is argued that to a greater or lesser extent, all mathematical knowledge is empirical.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 54.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 69.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    This essay is based on a paper with the same title (but without the subtitle) read at a conference celebrating Harvey Friedman’s 60th birthday. Much of the text is taken verbatim from that paper.

  2. 2.

    Feferman et al. (2003), vol. IV, pp. 502–505.

  3. 3.

    Feferman et al. (2003), vol. III, p. 312.

  4. 4.

    Feferman et al. (2003), vol. V, p. 204.

  5. 5.

    Feferman et al. (2003), vol. III, p. 313.

  6. 6.

    Feferman et al. (2003), vol. III, p. 50.

  7. 7.

    A proof did not appear until the next millennium! See Green and Tao (2008).

  8. 8.

    This was a celebrated result because the unsolvability of Hilbert’s tenth problem was an immediate corollary (Davis et al. 1996).

  9. 9.

    Post (1994) p. 295.

  10. 10.

    van Heijenoort (1967) p. 371.

  11. 11.

    This discussion, including the quotations, is based on Paolo Mancosu’s wonderful monograph (Mancosu 1996).

  12. 12.

    The method of exhaustion typically required one to have the answer at hand, whereas with indivisibles the answer could be computed.

  13. 13.

    Emphasis is in the original.

  14. 14.

    Of course this conventional use of the Greek letter \(\pi \) has nothing to do with the number \(\pi = 3.14159\ldots .\)

  15. 15.

    Although Euler obtained this infinite product by using a doubtful analogy, Weierstrass eventually obtained it quite rigorously as a special case of a general theorem about complex analytic functions.

  16. 16.

    That there are infinitely many primes has been proved in many different ways. The first proof is already in Euclid. It is very simple and elegant. To show that given any finite collection of primes, \(p_1,p_2,\ldots , p_n\), there is another prime not in that collection, one multiplies together all the primes in that collection and adds 1:

    $$\begin{aligned} N = p_1p_2\ldots p_n +1 \end{aligned}$$

    Since none of \(p_1,p_2,\ldots , p_n\) are divisors of N, either N is itself a prime different from any of them or it is divisible by a prime different from them.

  17. 17.

    A similar conclusion is obtained heuristically in Hardy and Wright (1960) pp. 371–372 without probabilistic considerations.

  18. 18.

    Mancosu (1996) p. 172.

  19. 19.

    Because otherwise the consistency of ZF would be provable in ZF contradicting Gödel’s second incompleteness theorem. For that matter the set \(V_{\omega 2}\) cannot be proved to exist from the Zermelo axioms alone; in ZF its existence follows using Replacement.

  20. 20.

    Number theorists seem to regard the use of Grothendiek universes as a mere convenience. See McLarty (2010) for a careful discussion.

References

  • Barrow, J. D., & Tipler, F. J. (1986). The anthropic cosmological principle. Oxford: Oxford University Press.

    Google Scholar 

  • Boole, G. (1865). A treatise on differential equations. London: Macmillan and Co.

    Google Scholar 

  • Davis, M. (2005). What did Gödel believe and when did he believe It? Bulletin of Symbolic Logic, 11, 194–206.

    Article  MathSciNet  Google Scholar 

  • Davis, M., Putnam, H., & Robinson, J. (1961). The decision problem for exponential diophantine equations. Annals of Mathematics, 74, 425–436. Reprinted in S. Feferman (Ed.). (1996). The collected works of Julia Robinson (pp. 77–88). American Mathematical Society.

    Article  MathSciNet  Google Scholar 

  • Davis, M., Matiyasevich, Y., & Robinson, J. (1976). Hilbert’s tenth problem. Diophantine equations: positive aspects of a negative solution. In Proceedings of Symposia in Pure Mathematics, vol XXVIII: Positive Aspects of a Negative Solution (pp. 323–378). Reprinted in S. Feferman (Ed.). (1996). The collected works of Julia Robinson (pp. 269–378). American Mathematical Society.

    Google Scholar 

  • Feferman, S., et al. (1986–2003). Kurt Gödel collected works, volume I–V. Oxford: Oxford University Press.

    Google Scholar 

  • Frege, G. (1892). Rezension von: Georg Cantor. Zum Lehre vom Transfiniten. Zeitschrift fr Philosophie und philosophische Kritik, new series, 100, 269–272.

    Google Scholar 

  • Green, B., & Tao, T. (2008). The primes contain arbitrarily long arithmetic progressions. Annals of Mathematics, 167, 481–547.

    Article  MathSciNet  Google Scholar 

  • Hardy, G. H., & Wright, E. M. (1960). An introduction to the theory of numbers (Fourth Edition ed.). Oxford: Clarendon Press.

    MATH  Google Scholar 

  • Mancosu, P. (1996). Philosophy of mathematics and mathematical practice in the seventeenth century. Oxford: Oxford University Press.

    Google Scholar 

  • McLarty, C. (2010). What does it take to prove Fermat’s Last Theorem? Grothendiek and the logic of number theory. Bulletin of Symbolic Logic, 16, 359–377.

    Article  MathSciNet  Google Scholar 

  • Post, E. L. (1944). Recursively enumerable sets of positive integers and their decision problems. Bulletin of the American Mathematical Society, 50, 284–316. Reprinted: Davis, M. (1965, 2004). The undecidable. New York: Raven Press; New York: Dover. Reprinted: E. L. Post, & M. Martin Davis (Ed.). (1994). Solvability, provability, definability: The collected works. Birkhäuser.

    Google Scholar 

  • Putnam, H. (1975). What is mathematical truth? Historia Mathematica, 2, 529–533.

    Article  MathSciNet  Google Scholar 

  • Putman, H. (1995). Philosophy of mathematics: why nothing works. Works and life (pp. 499–511). Cambridge: Harvard University Press.

    Google Scholar 

  • Robinson, J. (1952). Existential definability in arithmetic. In: Transactions of the American Mathematical Society (Vol. 72, pp. 437–449). Reprinted in S. Feferman (Ed.). (1996). The collected works of Julia Robinson (pp. 47–59). American Mathematical Society.

    Google Scholar 

  • van Heijenoort, J. (Ed.). (1967). From Frege to Gödel: A source book in mathematical logic, 1879–1931. Cambridge: Harvard University Press.

    MATH  Google Scholar 

  • Weyl, H. (1944). David Hilbert and his mathematical work. Bulletin of the American Mathematical Society, 50, 612–654.

    Article  MathSciNet  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Martin Davis .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2018 Springer Nature Switzerland AG

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Davis, M. (2018). Pragmatic Platonism. In: Hellman, G., Cook, R. (eds) Hilary Putnam on Logic and Mathematics. Outstanding Contributions to Logic, vol 9. Springer, Cham. https://doi.org/10.1007/978-3-319-96274-0_10

Download citation

Publish with us

Policies and ethics