A Taxonomy of Scholastic Distinctions

A distinction is just a breaking or removal of identity between things, parts, concepts, or terms.

Here are the major types of distinctions made by scholastic philosophers, as taken from Bernard Wuellner’s Dictionary of Scholastic Philosophy.

Logical distinction = a difference dependent on thought, but not found in the thing itself because of no real plurality in the thing thought about. It may be either a nominal distinction or a virtual distinction (see below).

Nominal (purely mental) distinction = a distinction only between words or terms describing the same object without any distinction in the thing to correspond to these difference names.

Real distinction = a true lack of identity between things, or between their parts and principles, or between objective concepts antecedently to and independently of the mind’s distinguishing activity. A MAJOR real distinction exists between two separate or complete wholes (for example, I, Pat, am a numerically distinct substance from my wife, Christine); a MINOR real distinction between parts, between whole and part, or between substance and its absolute accidents.

Virtual distinction = a logical (mental) distinction between different aspects of only one essence or perfection where the being is actually one and indivisible but is rich enough to present various aspects of its reality to the mind; e.g., the distinction between the divine attributes or between the several transcendental concepts. It is sometimes called a metaphysical distinction or, again, a logical distinction with a foundational in reality.

Final note. Some concepts pick out the same thing in reality but express something different about it. For example, “nature” versus “essence.” Often these terms are used interchangeably, and indeed, they refer to the same thing in reality. However, essence is meant to highlight the principle in virtue of which something is the kind of thing that it is, whereas nature highlight the same principle as that in virtue of which a thing has the characteristic activities it does. Technically, this is a distinction of “reason reasoning” which falls under the category of logical distinction without a foundational in the reality.

PS - For those who want to go deeper into this subject, I recommend Fr. Peter Totleben’s The Palamite Controversy: a Thomistic Analysis.