2nd HPP-NL Workshop

In recent years, the philosophy of dualities has seen a rapid growth both in depth and breadth of topic. In this context, an especially important role has been played by the study of gauge/gravity dualities, or holography, i.e. dualities which relate a theory of quantum gravity in n+1 dimensions to a field theory without gravity in n dimensions. The goal of this talk is to discuss some interesting philosophical issues raised by the application of holography to certain condensed matter systems, in particular to strange metals. Since these systems can be studied in the lab, and moreover for features which are only modeled via the use of holographic means, this
application of holography promises interesting new insights into the possibility of experimentally testing quantum gravity hypotheses.

In particular, I will provide a simple introduction to the theoretical framework used to model strange metals within holography, i.e. so-called semi-holography, and I will discuss some interesting philosophical questions it gives rise to; in particular, I will focus on the relation
between semi-holography and full holography, the meaning of explanation in the semi-holographic context, the prospect for emergence within a duality relation in semi-holography, and the possibility of taking a realist stance towards the gravity dual of the field theory in semi-holography. Throughout, the goal will be to introduce these questions as interesting and worthy of further philosophical analysis, rather than on providing direct solutions to these issues.

Joint work with S. De Haro, M. Golden, U. Gursoy, S. Mukherjee, and H. Stoof.

Within the foundations of quantum mechanics, Grete Hermann is best known for her analysis of causality in quantum mechanics, and for her critique of von Neumann’s impossibility proof against the completion of quantum mechanics through hidden variables. I submit further that Grete Hermann is a central figure in understanding the complex of ideas loosely shared between Bohr, Heisenberg and others in the 1930s, and was partly instrumental in their very crystallisation. She was both a critic to whom especially Heisenberg and Weizsäcker responded (the latter also on behalf of Bohr), and the most systematic and articulate exponent of that complex of ideas. A ‘Copenhagen interpretation’ as generally understood from the 1950s onwards may have been largely Heisenberg’s creation, but a systematic view along those lines was arguably formulated already in the 1930s by Grete Hermann.

The talk addresses the issue of the import of convergence arguments in theory assessment. A first part is devoted to making the point of the different types of strategies based on convergence, providing new distinctions with respect to the existing literature. Specific attention is devoted to robustness vs consilience arguments and one representative example for each category is then discussed in some detail. These are (a) Perrin's famous robustness argument on behalf of the atomic hypothesis on the grounds of the concordance of thirteen different procedures to the same result for the Avogadro number; (b) the consilience argument motivating the trust in the viability of the extra-dimension conjecture in the context of early string theory. These two cases are expressly chosen in order to highlight possible differences, also including whether the convergence obtains in terms of empirical or theoretical procedures. In both cases, I argue, the evaluation of the assessment strategy similarly depends, in a significant way, on how the convergence argument is interpreted.