 Linnebo (2018) advances a proposal about how to conceive abstract objects by revising our understanding of Fregean biconditional principles of abstraction (see  subsection 3.4).  Some philosophers take these Fregean abstraction principles to be analytic sentences. For example, Hale &amp; Wright (2001; 2009) consider the two sides of an abstraction principle as equivalent as a matter of meaning; they ‘carve up content’ in different ways (to use Frege’s metaphor). But Linnebo (2018, 13–14) rejects this view and the view that such biconditional principles are analytic.