Rencontre avec Peter Verdée (UCL) organisée dans le cadre des séminaires OLOFOS "Scientific représentation(s) of causation"
In this programmatic talk I present a project to elaborate a new way to understand (human) mental causation (or better: mental causal claims). I approach this old question from a formal semantic point of view: I aim to understand in an exact way what people may mean when they make claims that entail a certain causal efficacy of genuinely mental properties and how communication with such expressions can be extremely useful. Expressions implying or presupposing mental causation are almost ubiquitous in human communication: people assign propositional attitudes to themselves and to other people, they engage in normative and manipulative language, they claim to reason, argue and discover. They use all this to predict, explain and intervene. And all this is done in a world that may very well be physically closed (whenever an event has a cause at time t, it is caused by a sufficient physical cause at t) or even deterministic.
However, causal exclusion arguments (CEA) have been presented that aim to show that mental causation is incompatible with physical closure. If one accepts physical closure (PC) and causal exclusion (CE), i.e. the thesis that an event cannot at the same time be caused by an already sufficient cause and a second different cause, one needs to conclude that there cannot be mental causes in a world that is physically closed. In recent debates philosophers have tried to resist CEA’s conclusion by arguing against PC or CE. I will make use of an interventionist account of causation (c causes e iff counterfactually intervening on c makes a difference in e). There is arguably no a priori reason why an interventionist cause should exclude the possibility of two causes occurring at the same time and so there may be a way to avoid CE in this framework.
The project aims to respond to two central questions:
(Q1) What is the precise meaning of causal claims in the interventionist sense? How exactly can we interpret the counterfactual conditionals used in interventionist causation and how does this affect the content of causal claims?
(Q2) Depending on the precise content of interventionistic causal claims analysed in (Q1), how can we interpret mentally causal claims in such a way that there is no inconsistency between the content of mental properties and the content of causal claims that have mental properties as antecedents?
These questions are to be answered in three steps: (1) present the possible ways to devise an intensional semantics of interventionistic causal claims, (2) present several possible ways to devise an intensional semantics of claims asserting mental properties, and finally (3) logically prove that certain ways to interpret causal claims allow for mental properties as causes. I propose the following central hypothesis:
The causal efficacy of genuinely mental properties lies in their universally modal content, specifically in the (possibly ceteris paribus) behavioural rules they entail, given an interventionist reading of causation.