Skip to main content
Log in

Proof, Explanation, and Justification in Mathematical Practice

  • Article
  • Published:
Journal for General Philosophy of Science Aims and scope Submit manuscript

Abstract

In this paper, I propose that applying the methods of data science to “the problem of whether mathematical explanations occur within mathematics itself” (Mancosu 2018) might be a fruitful way to shed new light on the problem. By carefully selecting indicator words for explanation and justification, and then systematically searching for these indicators in databases of scholarly works in mathematics, we can get an idea of how mathematicians use these terms in mathematical practice and with what frequency. The results of this empirical study suggest that mathematical explanations do occur in research articles published in mathematics journals, as indicated by the occurrence of explanation indicators. When compared with the use of justification indicators, however, the data suggest that justifications occur much more frequently than explanations in scholarly mathematical practice. The results also suggest that justificatory proofs occur much more frequently than explanatory proofs, thus suggesting that proof may be playing a larger justificatory role than an explanatory role in scholarly mathematical practice.

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

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1

(Source: JSTOR Data for Research)

Fig. 2

(Source: JSTOR Data for Research)

Similar content being viewed by others

Notes

  1. Cf. Mancuso (2008b, 135) on the problem of “giving an account of mathematical explanation of empirical phenomena,” which is a different problem from the one about the explanatory and justificatory role of proof in mathematics. In this paper, I am concerned with the latter, not the former. See also Mancuso (2018). For recent work on mathematical explanations in science, see Andersen (2018) and Pincock (2015).

  2. On the question, “What are mathematical explanations?” see Inglis and Mejía-Ramos (2019). Again, this question is beyond the scope of this paper. The focus of this paper is “the problem of whether mathematical explanations occur within mathematics itself” (Mancosu 2018). That is, in mathematical practice (specifically, in the published work of practicing mathematicians), are there “proofs that merely prove” or “proofs that are in some way enlightening” as well?

  3. Cf. Pease et al. (2018) who report some empirical support for their conjecture that “there is such a thing as explanation in mathematics.” Their empirical study, however, was not designed to find out how frequently explanations and justifications occur in mathematics.

  4. The empirical methods employed in this paper are the methods of data science and corpus linguistics, such as text mining and corpus analysis, rather than the empirical methods of social science. For examples of the former methods applied to questions in the philosophy of mathematics and logic, see Pease et al. (2018) and Mizrahi (2019). For an example of the latter methods applied to questions in the philosophy of mathematics, see Inglis and Aberdein (2014).

  5. Cf. Pease et al. (2018) who use ‘expla*’ and ‘underst*’ as explanation indicators.

  6. Dutilh Novaes (2019, 73) argues that, “In an explanatory proof, there should be no surprises: each step in the proof must be clear and evident, eliciting immediate understanding in whoever inspects the proof, thus ruling out unexpected ‘turns’”.

  7. For more on the relationship between philosophy of mathematics and argumentation theory, see Pease et al. (2009). Ashton and Mizrahi (2018a) use a similar methodology and the tools of data science to investigate appeals to intuition in philosophy. See also Ashton and Mizrahi (2018b) and Mizrahi (2019).

  8. The jcodes for the other mathematics journals tested in this empirical study are as follows: American Mathematical Monthly (amermathmont), Annals of Mathematics (annamath), Journal of Computational Mathematics (jcompmath), and Journal of the American Mathematical Society (jamermathsoci).

  9. See, e.g., McLarty (2008) for a use of a case study in the philosophy of mathematics.

  10. On methodological issues in philosophy of mathematics, see Cellucci (2013). On the use of case studies in philosophy of science, see Mizrahi (2020).

  11. For more on the application of text mining and corpus analysis methods to philosophy of logic and mathematics, see Pease et al. (2018) and Mizrahi (2019).

References

  • Andersen, H. (2018). Complements, not competitors: Causal and mathematical explanations. British Journal for the Philosophy of Science, 69(2), 485–508.

    Article  Google Scholar 

  • Ashton, Z., & Mizrahi, M. (2018a). Intuition talk is not methodologically cheap: Empirically testing the “received wisdom” about armchair philosophy. Erkenntnis, 83(3), 595–612.

    Article  Google Scholar 

  • Ashton, Z., & Mizrahi, M. (2018b). Show me the argument: Empirically testing the armchair philosophy picture. Metaphilosophy, 49(1–2), 58–70.

    Article  Google Scholar 

  • Baronett, S. (2016). Logic (3rd ed.). New York: Oxford University Press.

    Google Scholar 

  • Bestvina, M. B., Bromberg, K., Fujiwara, K., & Souto, J. (2013). Shearing coordinates and convexity of length functions on teichmuller space. American Journal of Mathematics, 135(6), 1449–1476.

    Article  Google Scholar 

  • Carter, J. (2019). Philosophy of mathematical practice-motivations. Themes and Prospects. Philosophia Mathematica, 27(1), 1–32.

    Article  Google Scholar 

  • Cellucci, C. (2013). Philosophy of mathematics: Making a fresh start. Studies in History and Philosophy of Science Part A, 44(1), 32–42.

    Article  Google Scholar 

  • Cherlin, G. (2016). On the relational complexity of a final permutation group. Journal of Algebraic Combinatorics, 43(2), 339–374.

    Article  Google Scholar 

  • Colyvan, M., Cusbert, J., & McQueen, K. (2018). Two flavours of mathematical explanation. In A. Reutlinger & J. Saatsi (Eds.), Explanation beyond causation: Philosophical perspectives on non-causal explanations (pp. 231–249). Oxford: Oxford University Press.

    Google Scholar 

  • Copi, I. M., Cohen, C., & McMahon, K. (2011). Introduction to logic (14th ed.). Upper Saddle River, NJ: Prentice Hall.

    Google Scholar 

  • Cullinane, M. J. (2013). A transition to mathematics with proofs. Burlington, MA: Jones & Bartlett Learning.

    Google Scholar 

  • Dutilh Novaes, C. (2019). The beauty (?) of mathematical proofs. In A. Aberdein & M. Inglis (Eds.), Advances in experimental philosophy of logic and mathematics (pp. 63–93). London: Bloomsbury Press.

    Google Scholar 

  • Fenton, W., & Dubinsky, E. (1996). Introduction to discrete mathematics with ISETL. New York: Springer.

    Book  Google Scholar 

  • Fogelin, R. J., & Sinnott-Armstrong, W. (2005). Understanding arguments: An introduction to informal logic (7th ed.). Belmont, CA: Thomson Wadsworth.

    Google Scholar 

  • Freniche, F. J. (2010). On Riemann’s rearrangement theorem for the alternating harmonic series. The American Mathematical Monthly, 117(5), 442–448.

    Article  Google Scholar 

  • Govier, T. (2010). A practical study of argument (7th ed.). Belmont, CA: Cengage Learning.

    Google Scholar 

  • Hanna, G., Jahnke, H. N., & Pulte, H. (2010). Introduction. In G. Hanna, H. N. Jahnke, & H. Pulte (Eds.), Explanation and proof in mathematics: Philosophical and educational perspectives (pp. 1–13). Dordrecht: Springer.

    Chapter  Google Scholar 

  • Hersh, R. (1991). Mathematics has a front and a back. Synthese, 88(2), 127–133.

    Article  Google Scholar 

  • Hinkis, A. (2013). Proofs of the Cantor-Bernstein theorem: A mathematical excursion. Basel: Springer.

    Book  Google Scholar 

  • Inglis, M., & Aberdein, A. (2014). Beauty is not simplicity: An analysis of mathematicians’ proof appraisals. Philosophia Mathematica, 23(1), 87–109.

    Article  Google Scholar 

  • Inglis, M., & Mejía-Ramos, J. P. (2019). Functional explanation in mathematics. Synthese. https://doi.org/10.1007/s11229-019-02234-5.

    Article  Google Scholar 

  • Komori, Y. (2013). Functional equations of Weng’s zeta functions for (G,P)/ℚ. American Journal of Mathematics, 135(4), 1019–1038.

    Article  Google Scholar 

  • Maddy, P. (1997). Naturalism in mathematics. Oxford: Oxford University Press.

    Google Scholar 

  • Mancosu, P. (2008a). Introduction. In P. Mancosu (Ed.), The philosophy of mathematical practice (pp. 1–21). New York: Oxford University Press.

    Chapter  Google Scholar 

  • Mancosu, P. (2008b). Mathematical explanation: Why it matters. In P. Mancosu (Ed.), The philosophy of mathematical practice (pp. 134–149). New York: Oxford University Press.

    Chapter  Google Scholar 

  • Mancosu, P. (2018). Explanation in mathematics. In E. N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy (summer 2018 edition). https://plato.stanford.edu/archives/sum2018/entries/mathematics-explanation/.

  • Marcus, R. (2018). Introduction to formal logic with philosophical applications. New York: Oxford University Press.

    Google Scholar 

  • Martel, Y., & Merle, F. (2011). Description of two soliton collision for the quartic gKdV equation. Annals of Mathematics, 174(2), 757–857.

    Article  Google Scholar 

  • McLarty, C. (2008). ‘There is no ontology here’: Visual and structural geometry in arithmetic. In P. Mancosu (Ed.), The philosophy of mathematical practice (pp. 370–406). New York: Oxford University Press.

    Chapter  Google Scholar 

  • Mizrahi, M. (2019). What isn’t obvious about ‘obvious’: A data-driven approach to philosophy of logic. In A. Aberdein & M. Inglis (Eds.), Advances in experimental philosophy of logic and mathematics (pp. 201–224). London: Bloomsbury Press.

    Google Scholar 

  • Mizrahi, M. (2020). The case study method in philosophy of science: An empirical study. Perspectives on Science, 28(1), 63–88.

    Article  Google Scholar 

  • Nievergelt, Y. (2002). Foundations of logic and mathematics: Applications to computer science and cryptography. Boston: Birkhauser.

    Book  Google Scholar 

  • Niss, M. (2006). The structure of mathematics and its influence on the learning process. In J. Maasz & W. Schlöglmann (Eds.), New mathematics education research and practice (pp. 51–62). Rotterdam: Sense Publishers.

    Google Scholar 

  • Overton, J. A. (2013). “Explain” in scientific discourse. Synthese, 190(8), 1383–1405.

    Article  Google Scholar 

  • Pease, A., Aberdein, A., & Martin, U. (2018). Explanation in mathematical conversations: An empirical investigation. Philosophical Transactions of the Royal Society A, 377(2140), 20180159. https://doi.org/10.1098/rsta.2018.0159.

    Article  Google Scholar 

  • Pease, A., Smaill, A., Colton, S., & Lee, J. (2009). Bridging the gap between argumentation theory and the philosophy of mathematics. Foundations of Science, 14(1–2), 111–135.

    Article  Google Scholar 

  • Pincock, C. (2015). Abstract explanations in science. British Journal for the Philosophy of Science, 66(4), 857–882.

    Article  Google Scholar 

  • Ren, Z. (2012). Banded Toeplitz Preconditioners for Toeplitz Matrices from Sinc Methods. Journal of Computational Mathematics, 30(5), 533–543.

    Article  Google Scholar 

  • Rozkosz, A. (2013). Stochastic representation of weak solutions of viscous conservation laws: A BSDE approach. Journal of Theoretical Probability, 26(4), 1061–1083.

    Article  Google Scholar 

  • Sylvester, J. (1886). Lectures on the theory of reciprocants. American Journal of Mathematics, 8(3), 196–260.

    Article  Google Scholar 

  • Walton, D. N. (2002). Legal argumentation and evidence. University Park, PA: The Pennsylvania State University.

    Google Scholar 

  • Weintraub, S. H. (1997). Differential forms: A complement to vector calculus. New York: Academic Press.

    Google Scholar 

  • Zelcer, M. (2013). Against mathematical explanation. Journal for General Philosophy of Science, 44(1), 173–192.

    Article  Google Scholar 

Download references

Acknowledgements

I am grateful to two anonymous reviewers of the Journal for General Philosophy of Science for their helpful comments on an earlier draft of this paper.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Moti Mizrahi.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Mizrahi, M. Proof, Explanation, and Justification in Mathematical Practice. J Gen Philos Sci 51, 551–568 (2020). https://doi.org/10.1007/s10838-020-09521-7

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10838-020-09521-7

Keywords

Navigation