A compromise between the behaviourist views and the psychological views is to say that belief is characterised in part by its role in decision making. This leaves room for belief to play an important role in other things, like assertion or reasoning and inference. So the answer to the question “What is degree of belief?” is: “Degree of belief is whatever psychological factors play the role imputed to belief in decision making contexts, assertion behaviour, reasoning and inference”. There is room in this characterisation to understand credence as measuring some sort of psychological quantity that causally relates to action, assertion and so on. This is a sort of functionalist reading of what belief is. Eriksson and Hájek (2007) argue that “degree of belief” should just be taken as a primitive concept in epistemology. The above attempts to characterise degree of belief then fill in the picture of the role degree of belief plays.