Typology of pitfalls for causal analyses in physics The case of capillary forces

Abstract

The reasoning errors of experts in teaching or popularization situations are always surprising. However, they often correspond to “complexity-reducing” schemes, some of which have been categorized for a long time, especially concerning the role of causality. If we restrict ourselves to cases where the reasoning in question leads to the correct result and excludes technical errors, there is still a range of relatively unknown types of invalidity - even though they are in fact very well represented in teaching and popular science practices. The aim of this presentation is to highlight the importance of situating these types of reasoning in a list of problematic explanatory situations previously identified. After a quick reminder of the most well-known elements of such a list, such as “functional reduction” and “linear causal reasoning”, the presentation will focus on cases where the demonstration used seems to surreptitiously remove from the explanatory landscape one of the relevant variables of the phenomenon to be explained. Various examples will show that such a case can be observed in very diverse fields of physics. A case concerning capillary forces - the “liquid bridge” - will introduce a discussion we can have as educators according to our more or less informed treatment of these explanatory situations. At stake: conceptual coherence.