Luis Estrada-González (LEG): Could you tell our readers about your intellectual history?

Atocha Aliseda (AAL): I hold a bachelor degree in mathematics from UNAM and a PhD in philosophy and symbolic systems from Stanford. During my undergraduate studies I was interested in computer science, but at that time (mid-Eighties) bachelor programs in that area were nonexistent in Mexico. People with interests like mine studied mathematics, where it was possible to get a heavy load of logic courses and some computing ones. My bachelor thesis was a computer program (in Prolog) for the teaching of propositional logic. Soon after I graduated, I became research assistant to a philosopher, and wrote with him my first paper on automated reasoning. Before that, my first job at the university was as editorial assistant in Mathesis, a journal in the history and philosophy of mathematics. As you might have already noticed, I was (and still am) interested in many subjects, so it was not clear what I should do after my undergraduate studies. I was of course interested in mathematics, but was not really aiming at a doctorate in mathematics. I was interested in philosophy and in linguistics. I did not know I was indeed looking for an interdisciplinary program, until I found (through the post and libraries like the one at the American Embassy in Mexico, in a time with no internet) Philosophy and Symbolic Systems at Stanford and Pure and Applied Logic at Carnegie Mellon. Symbolic Systems at Stanford turned out to be a great option for me. It is run by the Philosophy Department, but it involves others as well (Linguistics, Psychology, Mathematics, and Computer Science). I finished my doctorate and returned to Mexico in 1997 as a researcher at the UNAM’s Institute for Philosophical Research. Soon thereafter, I attended the Congress of Logic, Methodology and Philosophy of Science held in Cracow in 1999 and met Theo Kuipers there. He knew my thesis via Johan van Benthem, my supervisor at Stanford, and I told him I was interested in continuing my work on abduction, especially the connection to issues in the philosophy of science. At that time, my home university was closed, due to a political turmoil. Sometime after our first encounter, Theo invited me to fill a one-year postdoc position at Groningen. I was desperate to continue my research and the strike at UNAM seemed endless, but I could not just leave my job behind. I suggested to Theo a somewhat unusual scheme of postdoc stay and, surprisingly, both him and my home university accepted. It turned out to be a three-year collaboration (2000–2002), three months every year at Groningen. I have wonderful memories of my time there.

LEG: Maybe some of our readers know of your work on abduction and how you applied it to some issues in the philosophy of science. We will address philosophy of science later, but given what you said about your intellectual history, could you tell us how you became interested in abduction?

AAL: I thank you for this question, for in general one cannot guess how it is that a researcher became interested on a topic merely by looking at her publications. I attended several logic courses given by van Benthem at Stanford and they were awesome. I discovered then there were many logics beyond classical logics, but my interest in abduction came from linguistics. Following a suggestion by Tom Wasow, I read “Interpretation as abduction”, by Jerry Hobbs and others. They claimed that the interpretation of a text can be accounted for by abduction: it is the minimal explanation of why the text would be true. I loved this idea. That was the kind of stu_ I wanted to investigate in my thesis, mainly from a logical and a computational perspective. My first attempt, however, was something impossible: to formalize Charles Peirce’s notion of abduction. But his notion of abduction is neither a single nor a clear-cut one, for his thoughts on the subject evolved throughout his life, and his reflection on abduction is so closely tied to the rest of his epistemology and semiotics, that it seems impossible to formalize it. I then decided to take Peirce rather as an inspiration, and put forward acharacterization of my own.

LEG: What was your PhD thesis about exactly?

AAL: In my dissertation “Seeking Explanations: Abduction in Logic, Philosophy of Science and Artificial Intelligence”, maybe one of the first PhD theses about abduction, my aim is to lay down logical and computational foundations in order to explore some of the formal properties under which abductive logics may be generated and evaluated. This approach naturally led me to connections with theories of explanation in the philosophy of science and to computationally oriented theories of belief change in artificial intelligence.

LEG: I understand you applied your research on abduction to the philosophy of science, especially to the processes of discovery and explanation. What are your views on this, and how have they evolved?

AAL: As a result of my postdoc research, I wanted to write a book on abduction, with some new results on the logical part as well as on the philosophical one. When I came to work with Theo Kuipers he told me something along the following lines: “Your model is very nice, but it is not good for philosophy of science because it is merely propositional. You need first order logic to represent scientific laws.” He was right. There were as well some issues in the literature on logics of discovery in the philosophy of science that I needed to study further. Working at UNAM in the postgraduate program in philosophy of science was very useful to me because I learned a lot by talking to my philosophy colleagues. At the same time, I had an interlocutor in Seville, Angel Nepomuceno, who had been working on second order logics and tableaux, and had some ideas as to how to modify tableaux in order to accommodate abduction in (some fragment of) first order logic. I visited him a couple of times while I was in The Netherlands, and we started a collaboration on this issue. Now, about abduction in discovery and explanation: On the one hand, Hans Reichenbach proposed a methodological distinction between the context of discovery and the context of justification, back in the Thirties of last century. This distinction served very well the positivist focus on justification issues from a logical point of view, but completely left out of the picture anything having to do with discovery. Fortunately, there are always philosophers working o_-track well-accepted ideas, and in this case, both Lakatos and Hanson raised the importance of heuristics, very much connected to abduction. But going back to the 19th century, there is of course Peirce, who thought of abduction as the logic for “synthetic reasoning”, a method for the generation of new ideas, as the adventuresome logic that gives us plausible hypotheses as the output of logical inferences. So, my book extends my dissertation in that I place my analysis on abduction within the discussion of logics of discovery, present my new results in logic, and included a chapter on Peirce and pragmatism, as well as an analysis of abduction connected to progress in empirical sciences, that I specifically worked on with Theo Kuipers.

LEG: What are the issues, problems or questions you are currently working on?