Real Distinction question

[Geremia]

Someone asked me:

Hello there, how have you been. A random thought came to mind when pondering the real distinction and wondered if you had any helpful reference. If we are to treat existence and essence as completely distinct, then how exactly do we consider essences to be real if they are not to be conflated with existence? For instance, if I stated that an essence exists then would that not immediately remove the distinction between existence and essence? How else are we to say that an essence is real if it is not identical to existence? 

[Geremia]

You seem to think that for something to be real, it has to be pure actuality (Actus Purus, God); you seem to think there cannot be degrees of reality. But for finite beings, there is always some degree of potentiality mixed in.

Your argument reminds me of Parmenides's for the impossibility of change. It's not that there is simply being (act) and non-being, but there are degrees of being in between (potentiality).

Thomistic Thesis #1 covers this:

Potency and Act so divide being that whatsoever exists either is a Pure Act, or is necessarily composed of Potency and Act, as to its primordial and intrinsic principles.

Lumbreras, O.P., commentates:

Every actual subsisting being—inanimate bodies and animals, men and angels, creatures and Creator—must be either Pure Act—a perfection which is neither the complement of Potency, nor the Potency which lacks further complement—or Potency mixed with Act—something capable of perfection and some perfection fulfilling this capacity. This statement is true both in the existential and in the essential order. In each of these orders the composition of Act and Potency is that of two real, really distinct principles, as Being itself; intrinsic to the existing being or to its essence; into which, finally, all other principles can be resolved, while they cannot be resolved into any other.