 There is some question, however, as to the extent to which Frege took logic to provide constitutive norms of thought.  Linnebo suggests that Frege eventually rejected this idea. Though he offers various arguments for thinking that Frege moved away from the constitutivity thesis, his [Linnebo’s] main argument concerns the fact that Frege wanted to position Basic Law V as a logical claim, but that Basic Law V doesn’t seem to be a constitutive norm of thought (Linnebo 2003, 247).  This is a persuasive reason, though it does make one wonder what Frege could have meant, in the second volume of Grundgesetze (§147), when he said, concerning Basic Law V: