In scholastic philosophy, Actus Purus (Latin for 'Pure Actuality' / 'Pure Act') is the absolute perfection of God.
[1] (Contrast this understanding with the Essence–Energies distinction in Eastern Christian, particularly Palamite, theology).
Both pairs – matter and form, essence and being – are special cases of potency and act.
The intensive Being includes every possible determination, thus excludes any other addition, is the highest real perfection; the common being is the highest abstraction and the lowest perfection, universal and totally indeterminate, indifferent to any addition (which neither excludes nor even includes).
[6] An univocal common being is the object of the philosophies of Parmenides and Plato,[7] as well as of Scotus, Suárez, and Wolff.
[7] The most perfect Being (or Esse ipsum subsistens, Being that subsists by itself and not in virtue of other-from-itself), is as strong and powerful, intelligent and free, noble and precious, profound and intimate to creatures, as nobody else can exist.