Thick concept

In philosophy, a thick concept (sometimes: thick normative concept, or thick evaluative concept) is a kind of concept that both has a significant degree of descriptive content and is evaluatively loaded. Paradigmatic examples are various virtues and vices such as courage, cruelty, truthfulness and kindness. Courage for example, may be given a rough characterization in descriptive terms as '…opposing danger to promote a valued end'. At the same time, characterizing someone as courageous typically involves expressing a pro-attitude, or a (prima facie) good-making quality – i.e. an evaluative statement.

A middle position

Thick concepts thus seem to occupy a 'middle position' between (thin) descriptive concepts and (thin) evaluative concepts. Descriptive concepts such as water, gold, length and mass are commonly believed to pick out features of the world rather than provide reasons for action, whereas evaluative concepts such as right and good are commonly believed to provide reasons for action rather than picking out genuine features of the world. This 'double feature' of thick concepts has made them the point of debate between moral realists and moral expressivists. Moral realists have argued that the world-guided content and the action-guiding content cannot be usefully separated, indicating that competent use of thick concepts constitutes ethical knowledge. Expressivists, favoring an account of moral values as attitudes projected onto the world, wants to uphold a distinction between the (morally neutral) descriptive feature of a thick concept and the evaluative attitudes that typically goes with them.