Jan von Plato


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Department of Philosophy, P.O.Box 24, 00014 University of Helsinki, Finland.
+ 358 - 9 - 191 28087 (office)
Fax :
+ 358 - 9 - 191 28060

New book!

Elements of Logical Reasoning, Cambridge University Press, 2013.
I obtained my doctorate at the University of Helsinki in 1980. From 1982 to 2000 I was mostly a Research Fellow at the Academy of Finland. In 1995-1996 I was Lecturer in Philosophy at the Department of Logic and Scientific Method of the London School of Economics. At present I am Professor of Philosophy at the Department of Philosophy, University of Helsinki (svensk professor i filosofi). From about 1990 to 1998 I led the research group on type theory and its applications at the University of Helsinki, Department of Philosophy. The group was part of the European Types Working Group. Insufficient funding led to an end of the group's activities.

Research interests

Most of my early research has been in the foundations of probability, where my main work is the book Creating Modern Probability, a historical-philosophical account of the birth of modern probability theory. (N.B. A paperback edition is also available). In the history and philosophy of science, I have also done work on probabilistic causality, and the methodology of the exact sciences, with a paper on analysis and synthesis in Ptolemaic astronomy.

After I "quit probability" in 1992, I worked for some years on elementary intuitionistic axiomatics, especially intuitionistic geometry, related to the type theory group. (Gilles Kahn's implementation of my axiomatics of constructive geometry was one of the first such implementations.) The most important part of the group's work was Aarne Ranta's type-theoretical grammar. It led later to his Grammatical Framework (GF) that can be found displayed at his home page.

From 1997 on, I have mainly worked on proof theory, both systematically and with historical-foundational questions in mind. There are three books: Structural Proof Theory , written with Sara Negri and published by Cambridge University Press in 2001 (paperback edition 2008), Proof Analysis: A Contribution to Hilbert's Last Problem, written with Sara Negri, Cambridge University Press, 2011, paperback 2014, and Elements of Logical Reasoning, Cambridge University Press 2013. The last one began as an elementary textbook, but became also a statement about my views on logic more generally. A historical appendix describes the development of the deductive machinery of logic from Aristotle to 1930. Another appendix contains a new proof of normalization by induction on the last rule in a derivation, and the interpretation of arbitrary cuts in terms of natural deduction.

I had the good fortune to find a handwritten manuscript version of Gentzen's doctoral thesis in February 2005. It turned out that the ms. contained a detailed proof of normalization for intuitionistic natural deduction. There is an English translation of the proof in item II.44. I have been preparing since many years Gentzen's shorthand notes for publication and hope to come out with a first volume in 2015.

Thematic List of Publications

For early papers on proof theory see also the reasoned bibliography and Sara Negri's homepage. Links to my papers are best found through my Google Scholar page.

I History and philosophy of science

II Logic and foundations

III Reviews

I History and philosophy of science

II Logic and foundations

III Reviews

Last modified January 13, 2015