Logical possibility

Philosophers generally consider logical possibility to be the broadest sort of subjunctive possibility in modal logic. The notion can be glossed by the popular description of logically possible propositions as those that can be asserted without any logical contradiction. Another way of saying this is that a proposition is logically possible if and only if there is some coherent way for the world to be, under which the proposition would be true. Thus, "the sky is blue" (and all other actually true propositions) is logically possible: there is a logically coherent way for the world to be such that it is true, viz., the way that the world actually is. But this "way for the world to be" need not be the way the world actually is; it need only be logically coherent. So, for example, the false proposition the sky is green is also logically possible, so long as we are able (as we indeed seem to be) to conceive of some logically coherent world in which the sky is green.
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