 Thus logical laws are primarily descriptive laws even though, like other descriptive laws, they too can be reformulated or apprehended as prescriptive laws. These distinctions allow Frege to distinguish between two versions of ‘psychological logicians’: one group takes the laws of logic to be descriptive psychological laws, the other group interprets the laws of logic as prescriptive laws based on descriptive psychological laws. It is the ambiguity of the expression ‘law of thought’ that invites these confusions (1893, XV).