Philosophers of science have produced a variety of definitions for the notion of one sentence, theory or hypothesis being closer to the truth, more verisimilar, or more truthlike than another one. The definitions put forward by philosophers presuppose at least implicitly that the subject matter with which the compared sentences, theories or hypotheses are concerned has been specified, and the property of closeness to the truth, verisimilitude or truth likeness appearing in such definitions should be understood as closeness to informative truth about that subject matter. This monograph is...