Abstract: Science and practical life strive to identify the generating or constraining conditions for the existence and character of whatever states of affairs concern them. Yet some conditions for phenomena within nature or for nature itself may be unidentifiable because there are no empirical data testing hypotheses about them or because relevant data are inaccessible. Three conditions external to nature are considered: God, eternal possibilities, and events priori to or consequent on the Big Bang. Empirical data confirming the existence and (...) character of the first two are lacking; evidence relevant to the inception and effects of the third is inaccessible. Nature has conditions that will likely remain unknowable; the world is likely to be more complicated than we can know. Speculations about the existence and character of its silent conditions won't be deterred, though the absence of justifying empirical data entails that speculation doesn't justify belief. (shrink)