Intuitively, essentialism limits the de re possibilities for individuals, while haecceitism extends the de re possibilities for individuals by admitting contentious possibilities—e.g., the possibility where you swap qualitative roles with Obama. It is important to note, however, that even the strongest versions of essentialism, hyperessentialism, do not rule out haecceitism. For, while hyperessentialism does rule out haecceitistic differences where you have different properties, it does not rule out a “mass replacement”—i.e., an alternative maximal possibility where wholly different individuals occupy each of the qualitative roles occupied in the actual world. These maximal possibilities differ haecceitistically even while there is no violation of essence, since no individual exists according to more than a single world. (Those who reject possibilities involving non-actual or “alien” individuals would, however, have the makings of an argument from hyperessentialism to anti-haecceitism.) Although essentialism provides no direct argument against haecceitism, hyperessentialism and other strong versions of essentialism do preclude certain kinds of haecceitistic differences where individuals “swap” qualitative roles. For example, just as hyperessentialism rules out any haecceitistic possibilities where you have a different qualitative role, origin essentialism rules out haecceitistic differences that involve organisms having anything other than their actual biological origins. For this reason, a commitment to strong versions of essentialism will constrain the range of admissible haecceitistic differences.