** Philosophy and Foundations of
Mathematics **

“How is pure mathematics possible?” is a chapter title of one of Kant’s books. Plato, Descartes, Leibniz, Frege, Husserl, Russell, Wittgenstein, Quine and other great philosophers have accorded a fundamental role to questions in the philosophy of mathematics. We may even say (with J. P. Mayberry) that it is this feature of western philosophy that sharply distinguishes it from the other great philosophical traditions. The interest in the philosophy of mathematics has various reasons. Let me mention two. Firstly, mathematics is the vintage example of a domain of knowledge whose truths are not (or do not seem to be) rooted in experience. How is that possible? Secondly, some of the deepest problems in philosophy find their most perspicuous formulation when they are specialized to mathematics and its foundations.

Working mathematicians have also been interested in the foundations of their subject. This was specially true in the first
quarter of the last century, when Poincaré, Hilbert, Weyl, Brouwer et al. have passionately debated the foundations of
mathematics. Foundational doctrines are strongly informed by technical results in mathematical logic and, at times, they can even
be carved out and made precise, opening the possibility of their *mathematical* development and/or refutation. Historically,
as it is well known, refutation has actually happened in some cases. Take, for instance, the refutation of the Fregean brand of
logicism by Russell's paradox, or the downfall of Hilbert's original programme due to Gödel's incompleteness theorems. At
other times, like with any philosophical issue, philosophy of mathematics seems prone to irremovable ambiguity. “There is no
mathematical substitute for philosophy,” said Saul Kripke; “not even for the philosophy of mathematics,” I would
add. It is this sweet combination of mathematical rigour and philosophical reflection that makes the foundations and philosophy of
mathematics such a fascinating subject.

*Papers not yet published should be considered drafts. Do not cite them without my permission.*

*Concerning the published papers, please note that what is posted are* manuscripts * from which the
published versions were created. There will be some differences between the manuscripts and the published versions. Should you
actually want to cite a paper, please consult the published version.*

Papers:

Zigzag and Fregean arithmetic. In: “The Philosophers and Mathematics”, edited by H. Tahiri. Logic, Epistemology, and the Unity of Science 43, Springer International, 2018, pp. 81-100.

Categoricity and mathematical knowledge. Revista Portuguesa de Filosofia 73(3-4), pp. 1423-1436 (2017).

On the notion of object - A logical genealogy. Disputatio 24, pp. 609-624 (2012).

A most artistic package of a jumble of ideas. dialectica 62, pp. 205-222, 2008. Special commemorative number of the fiftieth anniversary of Kurt Gödel's paper

*Über eine bisher noch nicht benützte Erweiterung des finiten Standpunktes*in this journal. Guest editor: Thomas Strahm.The co-ordination principles: a problem for bilateralism. Mind 117: 1051-1057, 2008.

To catch one's own shadow. In: “Actas do Segundo Encontro Nacional de Filosofia Analítica”, edited by Sofia Miguens, João Alberto Pinto and Carlos Mauro. Faculdade de Letras da Universidade do Porto, Porto 2006, pp. 14-16.

Comments on predicative logic. Journal of Philosophical Logic 35: 1-8, 2006.

Amending Frege's

*Grundgesetze der Arithmetik*, Synthese 147: 3-19, 2005.On the consistency of the Delta-1-1-fragment of Frege's Grundgesetze, with Kai Wehmeier. Journal of Philosophical Logic 31: 301-311, 2002.

A note on finiteness in the predicative foundations of arithmetic, Journal of Philosophical Logic 28: 165-174, 1999.

A substitutional framework for arithmetical validity, Grazer Philosophische Studien, 56: 133-149, 1998/9.

www.springer.com/us/book/9783319937328

https://www.jstor.org/stable/26291344

Doi: 10.1111/j.1746-8361.2008.01134.x

https://loja.up.pt/pt/produto/analises-actas-2-ordm-encontro -nacional-de-filosofia

Doi: 10.1007/s10992-005-9001-z

Doi: 10.1007/s11229-004-6204-8

Book Reviews:

Of A Course in Mathematical Logic for Mathematicians (2nd edition), Yuri Manin (with collaboration by Boris Zilber), Graduate Texts in Mathematics, Springer 2009. Newsletter of the European Mathematical Society 78, pp. 61-63 (2010).

Of Fixing Frege, John Burgess, Princeton University Press, 2005. Australasian Journal of Philosophy 84(3), pp. 464-466 (2006).

[The above papers are available for personal use only. In most cases, copyright resides with the publisher.]

Please note that, to view the on-line papers, or to print them out, you need already to have, or will need to download, a copy of the Adobe Acrobat Reader.