 The next obvious source of content for the modal fiction is the literal truth about our actual world (Rosen 1990, p. 335). The addition of all literally true non-modal propositions (in a suitable sense of “non-modal”) to the fiction as part of its description of the actual world is useful, since it provides a rich source of content that can be extended by, for instance, a principle of recombination, to yield claims about non-actual worlds. It would also seem to be required, for if the fiction fails to be committed to the actual world verifying a certain non-modal truth q, the inference from q to Actually-q and back will be jeopardised. Some particular non-modal truths may prove especially useful: Armstrong 1989, pp. 138–139 mentions analytic truths, truths in virtue of the meanings of terms, in this connection. One can either add the actual-world non-modal content by including an “encyclopedia” in the fiction, as Rosen does, or one could allow it in by, for example, stipulating as extra bridge-laws biconditionals of the form: