Philosophy of science

 

I greatly enjoy being a part of the "Peebles Fan club" discussion group organised by Niels Martens after attending the workshop on the philosophy of dark matter organised at the Lichtenberg Group for History and Philosophy of Physics at the University of Bonn. The history and philosophy of science are important parts of cosmological knowledge gain because we must not forget the development of our viewpoints and the original context in which they grew. Beyond that, philosophy of science provides us with a powerful formal framework to discuss the underlying fundamental concepts of our scientific theories. Some basics need to be assumed that cannot be proved with empirical evidence and a relationship between our universe and our picture thereof must be established.

Here are some examples that raised my interest:

• In the book Cosmology's Century, P. J. E. Peebles describes in detail that our interpretations of missing masses, leading to the introduction of a non-luminous new kind of matter, were greatly inspired by the assumption of stable, gravitationally bound cosmic structures and guided by analytical estimates using simple symmetry assumptions. 
• Jaco de Swart's work on the historical development of our cosmological model and its ingredients over the last century made me realise how many human biases and simplistic assumptions advanced the science of the sparsest data basis into today's precision cosmology. Astoundingly, many of the naive assumptions postulated to explain cosmic phenomena turned out to be good approximations to the increasing amount of data. 
• Bill Vanderburgh's work on the philosophy of dark matter argues that the usage of multi-messenger observations could increase the trust in the existence of this form of matter. Finding several independent hints for dark matter that refute the hypothesis the same observations could be caused by alternative theories of gravity is of great interest as long as we are missing a direct detection of any proposed particle candidate.
• Helen Meskhidze's work deals with the role of computer simulations for astrophysical and cosmological knowledge gain, which is a great inspiration for the project on cosmic structures and the derivation of mass density profiles from a discrete set of simulated particles. 
• Attending a talk by Eric Curiel, I learnt more about the hierarchy of (mathematical) assumptions underlying General Relativity and the individual implications of each level for the final theory. The relationship between kinematics, dynamics and the structure of a physical theory is particularly interesting as cosmic structure evolution is based on such prerequisites.
• After attending a talk by Kevin Coffey, I discovered ansatzes to connect the real world with our scientific theories in a consistent and (hopefully) true way. Thoughts along this direction are a necessary ingredient for approaches like "Lensing of '69" in order to assign the variables in the formalism a part of physical reality and determine those reduced variables (i.e. combinations of variables that can be directly constrained by observations) that can be attributed a meaning in the real world as well. Models based on artificial neural networks usually lack this connection and are therefore difficult to interpret and validate. 
• To learn more about the role of causality on our inference process, I attend the colloquium series on Understanding the Nature of Inference in Yale's Franke Program supported by the John Templeton Foundation.
• Last but by far not least, I have greatly enjoyed numerous inspirations and discussions with Rüdiger Vaas for about two decades. He was the first to raise my interest in philosophy.