Understanding Ordo Essendi vs Ordo Cognoscendi, and the Ambiguity of Aristotelian Semantics

When discussing metaphysical frameworks, it is crucial to understand two perspectival framings in which the semantics may be rooted: Ordo Essendi and Ordo Cognoscendi, Latin for the "order of being" and the "order of knowing", respectively.

Ordo Essendi concerns that which is first in itself; it assesses the order in which things proceed ontologically, beginning with that which is least conditioned and descending to that which is most conditioned. Accordingly, this view is regarded as "top-down". In this framing, the particular and sensible are predicated upon, and determined by, the essential and intellectual, with the former pairing partaking in the reality of the latter pairing.

Ordo Cognoscendi concerns that which is first for human perception; it assesses the order in which things are apprehended, beginning with that which is most immediate to the senses and abstracting to that which is grasped only by the intellect. Accordingly, this view is regarded as "bottom-up". In this framing, the essential and intellectual are predicated upon, and determined by, the particular and sensible, with the former pairing partaking in the reality of the latter pairing.

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The classification of a given metaphysical framework as either Ordo Essendi or Ordo Cognoscendi may at times be clear; and at others, tenuous.

For example, it is of no contest that the Platonic framework operates under the semantics of Ordo Essendi: It supposes that what is truly real are the transcendental Forms (Eide) and universals (together called the "intelligibles") that subsist in the World of Forms, and that the sensible things of the physical world are merely the generative "copies" of those Forms. Thus, it begins with the intellectual before descending to the sensible.

In precise terms, Plato holds that the intelligibles are "more real" than the sensibles, describing the intelligibles as principles possessing true being without becoming, and the sensibles as things that come to be and pass away but which never truly possess being (In other words, the intelligibles are, but do not become, because their becoming is the generation of the sensibles.):

"Therefore, in my opinion, we must first make this distinction: What is that which always is and has no becoming (τί τὸ ὂν ἀεί, γένεσιν δὲ οὐκ ἔχον), and what is that which is always becoming but never is (καὶ τί τὸ γιγνόμενον μὲν ἀεί, ὂν δὲ οὐδέποτε)? The one is grasped by intellect with reason, always remaining the same; the other is apprehended by opinion with irrational sense-perception, coming to be and passing away, but never truly being." - Timaeus 27d–28a

Meanwhile, whether the Aristotelian framework operates under Ordo Essendi or Ordo Cognoscendi is debatable: A Platonist may accuse the Aristotelian framework of operating under Ordo Cognoscendi semantics, insofar as Aristotle begins with particular substances before abstracting to the intelligible species to which they belong, thereby assigning primacy to that which is known first by human perception. However, an Aristotelian may counter that Aristotle's framework operates under Ordo Essendi, by asserting that it emphasizes the ontological primacy of substances before accidents and morphe, thereby assigning primacy to the thing in itself prior to the non-essential properties and shape by which thing is sensibly apprehended.

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This ambiguity of Aristotelianism's status as Ordo Essendi or Ordo Cognoscendi leads to several interesting consequences. I have outlined three of note below:

1.) The direction of predication is inverse with respect to the abstraction of cladal hierarchy.

On the one hand: Particular substances are resolved into species, and species into genera; reversely, through the addition of differences, genera are divided into species, and likewise species into particular substances. Accordingly, "genus" is cladally superior to "species", and "species" is cladally superior to "particular". Consequently, any particular belonging to a species is also included under the genus to which that species belongs.

On the other hand: Aristotle defines a particular substance as "that which is neither predicable of a subject nor present in a subject" (Categories, Ch 5), and asserts that the species (eidos) and genus to which the particular belongs are predicated thereupon and abstracted therefrom.

Given this, a Platonist may accuse that Aristotle's cladal hierarchy is rooted in Ordo Essendi insofar as it asserts universal categories over sensible particulars, but that Aristotle's direction of predication is rooted in Ordo Cognoscendi insofar as it predicates these categories upon particulars.

Now, "species" and "genus" are set apart not merely by rank, but by association and role: The species or form (eidos) is associated with intelligibility and differences; hence, inasmuch as species is formal, it is active, determining things to a "special grade of being" by supplying differences thereto. (Hence, the Theologian states that "difference [comes] from the form.") Meanwhile, the genus is associated with matter; hence, inasmuch as genus is material, it is potential; it is itself determined by the matter out of which things are constituted. (Hence, the Theologian states that "genus comes from the matter.")

(Supporting excerpts from Summa Theologia, PP, Q50, A4:

Obj. 1: "For everything which is contained under any genus is composed of the genus, and of the difference which added to the genus makes the species. But the genus comes from the matter, and the difference from the form (Metaph. xiii, text 6)."

Reply to Obj. 1: "Now, everything is constituted in a species according as it is determined to some special grade of being...*" | "But in material things, there is one thing which determines to a special grade, and that is the form; and another thing which is determined, and this is the matter. And hence, from the latter, the 'genus' is derived; and from the former, the 'difference'.")

If, in Aristotle's framework, the direction of predication aligned with the abstraction of cladal hierarchy, then "genus" would be superior in the order of being to "species", thereby asserting the material clade (genus) over the intellectual clade (species). This would undo Aristotle's metaphysical framework entirely, reducing it purely to materialism. However, because the direction of predication is inverse with respect to the abstraction of cladal hierarchy, the intellectual clade (species) is considered before the material clade (genus), and the latter is thereby predicated upon the former, thus averting materialism.

2.) Due to Aristotelianism's ambiguous semantics, philosophers examining his framework may reasonably disagree as to whether species and genera denote real categories of being or mere nominations. The former suggestion follows from an Ordo Essendi approach; the latter follows from an Ordo Cognoscendi approach. This debate is seen among the Scholastics:

Aquinas, through his concept of "second intention", holds that species and genera are not themselves the sign of anything in Reality, but are instead human nominations devised to describe a singular predicated of the many. Contrarily, Scotus argues that species and genera are created by God and were merely discovered by men through exercise of the intellect, rather than nominally prescribed post hoc:

"Hence, it is understood that the art of dialectic, which divides genera into species and resolves species into genera, was not fashioned by human devices, but created in the nature of things by the Author of all arts that are truly arts; and discovered by wise men and, by skillful research, adapted to use." - Periphyseon Book VI

3.) If both frameworks are taken as Ordo Essendi, then the Platonic and Aristotelian doctrines of formality may be co-affirmed.

Plato holds that form (eidos) is external to the locus of sensible things, operating in the transcendental register; while Aristotle holds that form is internal to the locus of particular substances, operating in the immanent register. For Plato, sensible things participate in the reality of the Forms; for Aristotle, form participates within the reality of particular substances. Here, Platonists may accuse that Aristotle's framework, once again, operates under Ordo Cognoscendi insofar as the intellectual (formal) is subordinated to the sensible (substantial). However, Aristotelians would contest this and assert, once again, that their framework is actually operating under Ordo Essendi insofar as, by placing form inside the locus of a particular substance, they render the particular substance to be that which is intelligible in itself. Consequently, it is possible to synthesize the two frameworks by asserting that each is simply interfacing with a separate but co-subsisting register of form, with transcendental formality denoting "derived intelligibility" and immanent formality denoting "intelligibility in itself".