Kosmas Brousalis MA

March 1 - August 31, 2026

Affiliation: National and Kapodistrian University of Athens, Greece

Research for a study about:

Confronting Tensions within Structural Realism: Lessons from the Logical Positivist Tradition

Confronting Tensions in Epistemic Structural Realism: Insights from the Logical Positivist Tradition
Epistemic structural realism (ESR) is a modestly realist epistemological position holding that our knowledge of the unobservable world is limited to its “structure” rather than its “nature.” My project stems from the observation that ESR—most prominently in its Ramseyan formulation—harbors an internal tension. This tension traces back to the considerations motivating ESR, which fall into two categories: semantic and historical. On the one hand, ESR is often taken to follow from a descriptivist Carnap–Lewis semantics of theoretical terms. On the other, it is intended as a realist position capable of accommodating revolutionary theory change. However, I argue that the semantic considerations imply the failure of the historical ones.
This tension has remained strikingly underexamined. The central aim of the project is therefore to clarify it and to develop a novel structuralist framework that reconciles the diverse—and often conflated—semantic and historical insights that originally ushered ESR into contemporary philosophy of science. I call this framework Multiplicative ESR.
Roughly speaking, Multiplicative ESR counsels epistemic restraint regarding the prospects of veridically “visualizing” unobservable entities—that is, representing them using observational concepts rooted in our sensory perception of the macroscopic world. In this respect, it aligns with concerns central to the logical positivist tradition, where a recurring theme is that representing unobservables using “relatively familiar notions […] whose content can be visually imagined” constitutes a “potential intellectual trap” [1]. A final objective of the study is therefore to examine the relationship between Multiplicative ESR and logical positivism, highlighting not only affinities but also apparent differences—particularly with regard to the unificatory aspect of scientific theorizing.
[1] Nagel, E. 1961. The Structure of Science. Routledge and Kegan Paul.

Lecture

Confronting Tensions within Epistemic Structural Realism: Lessons from the Logical Positivist Tradition

IVC Philosophy of Science Colloquium 

Date: June 11, 2026

Time: 4.45 pm -6.15 pm CET

Venue for all talks: Lecture Hall 3c, NIG Universitätsstraße 7, 3rd floor, NIG/ Neues Institutsgebäude, Universitätsstraße 7, 1010 Vienna

Abstract:
Epistemic structural realism (ESR) is a moderate realist position according to which our knowledge of the unobservable world is limited to its “structure” rather than its “nature.” This thesis is commonly explicated using Ramsey sentences and is thereby equated with the claim that, for any successful scientific theory, the most we can be realists about is the propositional content captured by its Ramsey sentence. ESR is typically motivated by two considerations: semantic and epistemic. On the one hand, it is taken to follow from a descriptivist Carnap–Lewis semantics of theoretical terms; on the other, it is presented as the only realist epistemological position capable of accommodating revolutionary theory change.
In this talk, I argue that endorsing both considerations results in inconsistency. After clarifying the tension and outlining the desiderata for any adequate resolution, I propose a novel variant of ESR, which I call Multiplicative ESR. Roughly speaking, this view counsels epistemic restraint regarding the prospects of veridically “visualizing” unobservable entities—that is, representing them using observational concepts rooted in our sensory experience of the macroscopic world. I then motivate Multiplicative ESR, explore its (possibly troubling) implications, and examine the relationship between key tenets of this view and themes in the logical positivist tradition.