Abstract:
This paper discusses how the so-called "abuse of the necessary a posteriori", proposed by Beebee and Sabbarton-Leary (2010), erroneously assumes that: a) necessary a posteriori statements require a metaphysical commitment to a non-trivial essentialism, and b) the thought experiment of the twin earth fulfills an evidential role in determining the necessary a posteriori. Against a), it is argued that the necessary a posteriori does not require a non-trivial essentialist commitment; at most, nontrivial essentialism is a consequence of the necessary a posteriori. Contra b), it is stated how the thought experiment of the twin earth fulfills a subsidiary, explanatory, and non-evidential role. This prevents an ontological commitment to the conceivable-possible connection. It is then discussed how the notion of rigid coreferentiality (de jure-de facto) is a way of solving the non-trivial essentialism requirement. Finally, we consider how Brian Ellis' scientific essentialism, in stating a priori conditions of satisfaction, does not affect the necessary a posteriori justification.
Keywords:
Necessity; A posteriori; A priori; Essentialism; Thought experiment