A new planet in the Solar System?

Killing Pluto was fun, but this is head and shoulders above everything else. (M. Brown)

It was only yesterday when I published a post on standard and non-standard existential predictions. Thus, I was very happy today when, opening the newspaper, I read that some astronomers have predicted the existence of a new planet in the Solar System! Michael E. Brown and Konstantin Batygin just published a paper on the current number of the Astronomical Journal, in which they argue in favour of the existence of a ninth planet, nearly the size of Neptune, orbiting the sun every 15,000 years. The news is also reported by the magazine Science. The existence of this “Planet X” has not been confirmed by any discovery yet, therefore for the moment this prediction is nothing but a simple hypothesis.

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Standard and non-standard existential predictions

Existential predictions are very rare in science. For this reason, when scientists can predict the existence of a new entity—a new planet, or a new particle, for example—we feel that something very exciting is going on! But what is going on is not only exciting—it is also very interesting from a philosophical point of view. These predictions raise various philosophically interesting puzzles, which relate to the epistemological, metaphysical, and methodological roles that mathematics can play in scientific representation. In this post, I want to present two main kinds of existential prediction in science and to sketch some philosophical problems related to them. However, I will not address these problems in this context. The interested reader may refer to Ginammi (2016) for a more detailed analysis and for a solution to these problems.1

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Avoiding Reification. A new article on the Studies in History and Philosophy of Modern Physics!

I am pleased to announce that my new article Avoiding Reification will be published on the volume 53 of the Studies in History and Philosophy of Modern Physics (February 2016)!

The article is already accessible online at this address. By clicking on this link until February 23, 2016, you will be taken to the final version of my paper on ScienceDirect for free! No sign up or registration!

In this article I have discussed and critically examined a very interesting case of existential prediction in particle physics: the prediction of the \varOmega^- particle (a particle of the class of the spin-\frac{3}{2} baryons). Existential predictions in science are always very thrilling, as you may imagine; but this prediction is even more interesting than usual because of the peculiar role that mathematics seems to play. Such a peculiar role raises a serious philosophical problem, since apparently we cannot justify it on the basis of standard methodological criteria. In this paper I discuss this problem and I offer a solution to it by offering a new logical reconstruction of the prediction of the \varOmega^- particle, based on the representative and heuristic effectiveness that mathematics may exhibit under certain conditions.

Here is the abstract of the paper, just to give you an idea of the content:

According to Steiner (1998), in contemporary physics new important discoveries are often obtained by means of strategies which rely on purely formal   mathematical considerations. In such discoveries, mathematics seems to have a peculiar and controversial role, which apparently cannot be accounted for by means of standard methodological criteria. M. Gell-Mann and Y. Ne׳eman׳s prediction of the \varOmega^- particle is usually considered a typical example of application of this kind of strategy. According to Bangu (2008), this prediction is apparently based on the employment of a highly controversial principle—what he calls the “reification principle”. Bangu himself takes this principle to be methodologically unjustifiable, but still indispensable to make the prediction logically sound. In the present paper I will offer a new reconstruction of the reasoning that led to this prediction. By means of this reconstruction, I will show that we do not need to postulate any “reificatory” role of mathematics in contemporary physics and I will contextually clarify the representative and heuristic role of mathematics in science.

Good read and happy new year to everybody!

From Logic to Practice. Italian Studies in the Philosophy of Mathematics

I’m happy to announce that the new book From Logic to Practice is now available on Amazon.com! My contribution, Structure and Applicability, can be found in Part III, chapter 11 of the book.

From Logic to PracticeThis book — it is written in the back cover — brings together young researchers from a variety of fields within mathematics, philosophy and logic. It discusses questions that arise in their work, as well as themes and reactions that appear to be similar in different contexts. The book shows that a fairly intensive activity in the philosophy of mathematics is underway, due on the one hand to the disillusionment with respect to traditional answers, on the other to exciting new features of present day mathematics. The book explains how the problem of applicability once again plays a central role in the development of mathematics. It examines how new languages different from the logical ones (mostly figural), are recognized as valid and experimented with and how unifying concepts (structure, category, set) are in competition for those who look at this form of unification. It further shows that traditional philosophies, such as constructivism, while still lively, are no longer only philosophies, but guidelines for research. Finally, the book demonstrates that the search for and validation of new axioms is analyzed with a blend of mathematical historical, philosophical, psychological considerations.​

Let me express my gratitude to Gabriele Lolli, Marco Panza and Giorgio Venturi, whose initiative and perseverance made this work possible.

Gödel on idealism and time travelling

[The following post is based on a seminar given at the Scuola Normale Superiore (Pisa) in June 2011. Here you can find the complete text of the talk (in Italian).]

Albert Einstein and Kurt Gödel

In 1946, Paul Artur Schilpp asked Kurt Gödel to write a paper to be included in the collective volume on Albert Einstein for the “Library of Living Philosophers” collection (edited by Schilpp himself). As shown by a letter from Schilpp to Gödel dated July 10th 1946, Gödel himself should have had to propose an argument for the paper, but he never replied. Schilpp, then, suggested he write an article on the topic: “The realistic standpoint in physics and mathematics”. But Gödel was hesitant: he thought himself to be insufficiently expert on the topic to worthily contribute. At the most, he considered himself able to contribute some considerations on the notion of time as resulting from Einstein’s theory of relativity and on the relationship between this and the idealistic thesis of the non-existence of objective time. Schilpp was enthusiastic and thus, three years later (in 1949), a short article was published under the title “A remark about the relationship between relativity theory and idealistic philosophy”1

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Conference: The Analysis of Theoretical Terms

Next week I will be in Munich for a conference on theoretical terms at the Munich Center for Mathematical Philosophy (MCMP). I will talk about the role of mathematics in a very interesting case of existential prediction in physics: the discovery of the omega minus particle. Here is the website of the conference.

Turkeys, swans and groups

Everybody knows the story of the turkey appearing in the title of this blog: on his first day at the farm, a turkey observed he was fed at 9:00 a.m., and the same happened the following day, and the following, and the following again, and so on. Day by day he collected a large number of observations, under the most different circumstances. Every day, were it cold or warm, rainy or sunny, winter or spring, he was fed at 9:00 a.m. He was a good logician, thus he concluded: “I am always fed at 9:00 a.m.”. Well, the day after it was Thanksgiving and he had his throat cut. Continue reading