 But the rationalist project imposes specific constraints on how these questions are answered. To vindicate the “golden triangle”, the rationalist must identify a way of mapping an individual speaker’s understanding of particular expressions onto possible worlds that affords apriori access to the entire space of possibility. This is not a trivial requirement: standard ways of interpreting the 2D framework cannot vindicate the rationalist project. However Chalmers has developed a distinctive “epistemic” interpretation of the 2D framework that he believes can establish the relevant constitutive links between meaning, apriority and possibility (2004, 2006a).