In this chapter, I want to try to rzedeem the pledge of stipulationism in (especially) the abstract sciences. At the same time, I wish to seek for consideration what might fairly be said to motivate the fundamental principle of dialethism, the existence, namely, of true contradictions. On the face of it, the place to pursue their objectives is in the theory of fiction, or in that branch of it known as the logic of fiction (Woods, 1974). Fiction is, or appears to be, a paradigm of truth-making stipulations, in the sentences made true by the author's sayso and those that follow from them under suitably constrained closure conditions. And fiction endorses, and thereby makes true, sentences having the character of contradictions – or so it would appear. A third reason for exploring the logic of fiction is the mere fact of fictionalism in the foundation of mathematics (Woods, 1974). It is a fact that summons up an initially attractive principle: