Ulrich Gähde
University of Hamburg
Spring Term 2018

Ulrich Gähde is a retired professor at the Philosophy Department of the University of Hamburg. He is also a member of the senate of the German National Academy of Sciences Leopoldina.

His main field of research concerns the logical structure and development of empirical theories in general and physical theories in particular. He is especially interested in holistic phenomena and, in particular, in how empirical theories react to anomalies – i.e. stubborn conflicts with observational data. How can such theories be defended against conflicts of this kind? What is the role of so-called theoretical terms here, and what are the limits to the immunisation potential of empirical theories?

His research project in Pittsburgh is part of this field. It concerns a seemingly simple problem: what are the criteria for deciding whether a given empirical theory is responsible for the theoretical description of a concrete system? In other words, how is the area of intended applications of a theory determined? The answers to these questions are obviously crucial for testing an empirical theory - they determine which systems are to be regarded as potential instances of corroboration or falsification. One natural answer is to first mark out a class of paradigmatic applications of a theory and to then insist that these applications – as well as any other systems that are sufficiently similar to them – can be successfully described with the help of the relevant theory. However, the terms “sufficiently similar” is obviously underdetermined in numerous respects. His research project addresses a specific aspect of this underdetermination: whether two systems are sufficiently similar depends crucially on the theoretical perspective under which they are regarded. By referring to case studies from astrophysics, he intends to show that this fact has significant consequences for the confirmation of the theories involved. The first case study refers to the well-known case of  the anomalous advance of Mercury’s perihelion. By contrast, the second refers to a system of binary stars that has not been analysed in the philosophy of science so far – although the corresponding anomalies have troubled astronomers for many decades.

Other fields of interest concern problems of model building and simulation, as well as comparisons between the structures of descriptive-empirical and normative-ethical theories.

Outside philosophy, Ulrich Gähde is a passionate sailor.