Prestigious research award
Lessons from Linda
“Have you met Linda?” asks Stephan Hartmann quite innocently. “Linda is 31 years old and single. She has a degree in Philosophy and campaigns actively against nuclear power. Now, which of the following statements is more likely to be true,” he says, leaning confidentially over the coffee table: ‘Linda works in a bank, or Linda works in a bank and is a feminist?’ – The second, you think? That’s not surprising,” he admits, with no hint of triumph in his voice, “but it’s wrong. The first statement is correct. The probability that two propositions are both true cannot exceed the probability that either one of them is valid: ‘secondly’ is always a subset of ‘first of all,” he explains, and scribbles a formula on a piece of paper. “Don’t worry, it’s a mistake that 85% of people make,” as Daniel Kahnemann and Amos Tversky showed in 1983, in a “famous experiment” on the heuristics of representation.
Hartmann the philosopher, who is 44 and was recently appointed to the Chair of Philosophy of Science at LMU, has no further use for Linda, but she does illustrate the kind of approach to philosophy he intends to explore in Munich, in collaboration with his colleague Hannes Leitgeb. Hartmann and Leitgeb, both internationally renowned practitioners in their field, are joint directors of the Munich Center for Mathematical Philosophy. They also share the distinction of having won Alexander von Humboldt-Professorships. These are Germany‘s most generously endowed awards for excellence in research, and enable world-renowned scholars from abroad to pursue long-term research projects at a German university. – Hartmann appears for the interview dressed in jeans, plaid flannel shirt and a bike helmet. Born in the State of Hesse, he has a firm handshake, an easygoing demeanor and an engaging manner.
Following in Popper’s footsteps
Hartmann studied Physics and Philosophy of Science in Gießen. “My colleagues in physics always thought I was wasting my time with philosophy. But the great advantage of philosophy is that one can take up anything one likes.” Having completed his doctoral studies on models and computer simulations in the sciences, he takes a position as Research Assistant to Professor Jürgen Mittelstraß in the Faculty of Philosophy at the University of Constance. “But it quickly became clear to me that I was unlikely to obtain a professorship in philosophy in Germany on the strength of my research,” he remarks modestly. “I just didn’t have the necessary historical depth and thematic range.” So, after spending a year in Pittsburgh (USA), and already firmly committed to the Anglo-American tradition of analytical philosophy, Hartmann joined the London School of Economics, where Karl Popper once taught. Once there, he quickly rises to the rank of professor – without a Habilitation (the postdoctoral qualification that is still generally required for such a position in Germany). At this point, Hartmann has no interest in going back to Germany. Instead, he accepts an offer from Tilburg University in the Netherlands, and builds up its new Center for Logic and Philosophy of Science. What finally induces him to return home is the award of the Humboldt Professorship, in combination with the opportunities offered by the Munich Center for Mathematical Philosophy, and the network of interdisciplinary collaborations at LMU.
Politically tricky issues
“I do philosophy in much the same way that a natural scientist approaches his subject. My starting point is often a concrete problem.” One such problem concerns decision-making by the EU Council of Ministers. That might sound like a tedious bureaucratic exercise, but it is actually a very complicated issue of great political significance. Not only are large amounts of money involved, the integrity of the EU as a whole is at stake. One way of allocating voting rights is to give each member state a single vote. That would mean, however, that every citizen of Malta would have the same political weight as 200 Germans. On the other hand, the converse model – in which voting rights are assigned in proportion to a country’s population – would effectively marginalize the smaller member states. An equitable solution should lie somewhere between these two extremes. The question is, where exactly? – But that is not just a mathematical problem, it is also politico-philosophical one.
It is precisely this interface between the empiricial, conventional practice and philosophy that fascinates Hartmann. “Linda stands for a philosophical question that will occupy us in the coming years: ‘How does probability theory, a mathematical construct, actually fit the world we live in?’” Hartmann is not someone who sits alone in his room brooding over the ultimate fate of humankind. “I do not believe that I can get very far by the power of pure thought alone.” Instead, he looks for mathematical models with which to tackle philosophical problems. For instance, how do norms originate? What do probabilities in physics really mean? – Are quantum mechanical probabilities simply a reflection of the limits of our knowledge about the state of an object or a system, or do they describe an objective indeterminacy that is inherent to nature? Note that questions of this kind are not just of philosophical interest; physicists working on practical applications of quantum information theory are increasingly confronting them.
With an eye to what’s practical
Hartmann is interested in questions that cannot be satisfactorily solved solely on their own terms and always have practical connotations. This is the reason why the Munich Center for Mathematical Philosophy, which he and Leitgeb lead, is a consciously interdisciplinary institution. Established investigators and up-and-coming youngsters, with diverse backgrounds in fields such as Economics and Political Science, Biology and Philosophy, Physics and Psychology, work here in teams. According to Hartmann, the Center’s mission is “to derive non-trivial consequences for concrete problems starting from philosophical positions. We want to show that philosophy has a real contribution to make. I would find it boring simply to collect butterflies,” he says. “The trick is to discover things that are philosophically exciting, and therefore of general relevance, and at the same time to relate these to the real world in interesting ways.” – That is why Stephan Hartmann is intent on bringing analytical philosophy’s airy flights back down to earth. Maximilian G. Burkhart