Motivating Non-Contingency

This chapter takes up the question of how to motivate the crucial ‘Non-Contingency’ premise in the Tolerance Puzzles introduced in Chapter 2, a question that has received surprisingly little attention in the literature on these puzzles. We articulate and set aside some dubious motivations for the premise, including motivations which assimilate Tolerance Puzzles to the well-known Sorites Paradox. In place of these, we develop a ‘Security Argument’ for Non-contingency, based on the thought that it is not just a matter of chance or luck that we avoid error in believing the Tolerance premise.