An essence exists if and only if it is actualized or concretized somehow, in some concrete form.

A dualtropic HIV strain uses both the CCR5 and the CXCR4 coreceptors.

One cannot lay a charge, a charge which has simply been sucked out of one's thumb, and then say that the onus rests on the person against whom the charge has been made, to prove that it is not so.

What is under erasure in the discussion of justice in the original position is all knowledge of the features that distinguish one person from another.