Speaker: José Ferreirós, Professor of Logic and Philosophy of Science at the University of Seville and member of the IMUS Institute of Mathematics

Date and time: Wednesday 25 November 2026 – 19:00

Venue: Residencia de Estudiantes de Madrid (Calle Pinar, 21-23, 28006 Madrid). Live streaming.

This activity is part of the Mathematics at the Residencia series and of Science and Technology Week.

Cantor (left) and Dedekind (right) exchanged a rich scientific correspondence.

Summary: Can infinity be determined? How could it be measured? Are some infinities larger than others? In the late 19th century, two German mathematicians, Georg Cantor and Richard Dedekind, exchanged dozens of letters trying to answer these questions. That correspondence gave rise to set theory, one of the great pillars of modern mathematics. Although it is usually attributed to Cantor alone, the credit in fact belongs (at the very least) to both of them. The letters reveal an extraordinary creative process, which we can observe almost in real time; they show how mathematical ideas are actually worked out, amid doubts, trial and error, critical revisions and personal relationships. This talk will trace that fruitful exchange, which raises questions about authorship and scientific ethics and shows the importance of communal work in mathematics.

About the speaker

José Ferreirós has edited Spanish-language editions of works by Dedekind and Cantor. Image courtesy of the researcher.

José Ferreirós is Professor of Logic and Philosophy of Science at the University of Seville and a member of the IMUS Institute of Mathematics. His work deals with the history andphilosophy of mathematics. He is the author of Labyrinth of Thought (Birkhäuser, 2007), a monograph on the development of set theory, and has edited Spanish-language editions of works by Riemann, Dedekind and Cantor. His main philosophical work is Mathematical Knowledge and the Interplay of Practices (Princeton, 2016), but he has also published popular science books such as De la geometría a la topología (EUS, 2023) and La génesis de la geometría (Plaza y Valdés, 2023). He has served as president of the Association for the Philosophy of Mathematical Practice (APMP), is a member of the International Academy of Philosophy of Science (AIPS, Brussels), and has taught and lectured widely across Europe and the Americas.

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This text has been automatically translated from Spanish and may contain inaccuracies.