A world where there exists n concrete things is a count-determinate world. The orthodox view is count-determinacy is necessary; if to be is to be the value of a variable and the domain of quantification is enumerable, count-determinacy follows. Yet I argue how many there are can be indeterminate; count-indeterminacy is metaphysically possible and even likely actual. Notably, my argument includes rebuttals of Evans’ reductio of indeterminate identity and the Lewis/Sider ‘argument from vagueness’. Count-indeterminacy should therefore be recognized as another (...) basic form of genuine metaphysical indeterminacy, in addition to types recently defend by Barnes, Williams, and Wilson. (shrink)