Mentalism versus behaviourism in economics: a philosophy-of-science perspective

Behaviourism is the view that preferences, beliefs, and other mental states in social-scienti�c theories are auxiliary constructs re-describing people's behav- ioural dispositions. Mentalism is the view that they capture real phenomena, no less existent than the unobservable entities and properties in the natural sciences, such as electrons and electromagnetic �elds. While behaviourism has long gone out of fashion in psychology and linguistics, it remains the dominant orthodoxy in economics, especially in the form of �revealed preference�theory. We aim to (i) clear up some common conceptual confusions about the two views in economics, (ii) situate the debate in a broader historical and philosophical context, and (iii) defend a mentalist approach to economics. Setting aside normative concerns about behaviourism, we show that mentalism is in line with best scienti�c practice even if economics is treated as a purely positive science of human social behaviour. We distinguish mentalism from, and reject, the radical neuroeconomic view that social behaviour should be explained in terms of people's brain processes, as distinct from their mental states.