It is Aristotle who first formulated the principles of correct definition. It is Aristotle who identified the fact that only concretes exist. But Aristotle held that definitions refer to metaphysical essences, which exist in concretes as a special element or formative power, and he held that the process of concept-formation depends on a kind of direct intuition by which man’s mind grasps these essences and forms concepts accordingly.
Aristotle regarded “essence” as metaphysical; Objectivism regards it as epistemological.
Objectivism holds that the essence of a concept is that fundamental characteristic(s) of its units on which the greatest number of other characteristics depend, and which distinguishes these units from all other existents within the field of a man’s knowledge. Thus the essence of a concept is determined contextually and may be altered with the growth of man’s knowledge. The metaphysical referent of man’s concepts is not a special, separate metaphysical essence, but the total of the facts of reality he has observed, and this total determines which characteristics of a given group of existents he designates as essential. An essential characteristic is factual, in the sense that it does exist, does determine other characteristics and does distinguish a group of existents from all others; it is epistemological in the sense that the classification of “essential characteristic” is a device of man’s method of cognition—a means of classifying, condensing and integrating an ever-growing body of knowledge.
It is important to note the various connections that Rand maintains between essence, concepts, and definitions. She begins by introducing the Aristotle's view of essence. For Aristotle, essences are "metaphysical." They exist "in" concretes as a special element or "formative power." Rand, however, regards these essences as "epistemological." I've attempted to unpack the meaning of this phrase in another post; I will focus in this post on another side of the issue.
There are two potential reasons why Rand dismisses the notion of "metaphysical" essences. The first reason is that she appears to believe that metaphysical essences would make concept formation too easy. I've already criticized this rationalization for dismissing metaphysical essences, so there's no need to add anything here. The second reason stems from the Aristolean notion that essences are a formative power which quite literally makes a thing what it is. Presumably Rand would have rejected this Platonic element embedded in Aristotle's thought. Essences are not powers; they are merely themes of discourse: a strand of identity by which one class of objects is distinguished from another.
Philosophically, essences are normally defined as "the attribute or set of attributes that make an entity or substance what it fundamentally is, and which it has by necessity, and without which it loses its identity." Rand seems to have regarded essences as being those attributes by which an object is defined. This is why essences are brought up in her chapter on definitions. Since the essence provides the materials out of which a definition is made, it would be no exaggeration to say that, for Rand at least, an essence constitutes a concept's definition.
Now there is one potential problem here that, as we begin to explore the essentialistic aspects of Rand's epistemology, will begin to assume greater importance. Rand regarded definitions as "the condensation of a vast body of observations." Definitions, Rand declared, are not descriptions. "If a definition were to list all the characteristics [of a concept's referents], it would defeat it's own purpose: it would provide an indiscriminate, undifferentiated and, in effect, pre-conceptual conglomoration of characteristics which would not serve to distinguish the units from all other existents, nor the concept from all other concepts. A definition must identify the nature of the units, i.e., the essential characteristics without which the units would not be the kind of existents they are." [IOTE, 42]
If, however, a definition does not exhaustively describe what a thing is; if it is a mere condensation of knowledge: then does this not imply that essences are also non-descriptive condensations as well? If so, this is deeply problematic. If an essence makes an object what it is, the implication here is that a condensation of knowledge, a handful of attributes rather than all the attributes of the object, are what make the thing what it is. But this position seems to imply the Aristotlean doctrine that essences are metaphysical (i.e., that they are formative powers).
Rand appears to embrace this position in another passage from her chapter on definitions:
Now observe ... the process of determining an essential characteristics [i.e., an essence]: the rule of fundamentality. When a given group of existents has more than one characteristic distinguishing it from other existents, man must observe the relationships among these various characteristics and discover the one on which all the others (or the greatest number of others) depend, i.e., the fundamental characteristic upon which the others would not be possible. This fundamental characteristic is the essential distinguishing characteristic of the existents involved, and the proper defining characteristic of the concept.
Metaphysically, a fundamental characteristic is that distinctive characteristic which makes the greatest number of others possible; epistemologically, it is the one that explains the greatest number of others. [IOTE, 45]
A few pages later [p. 52] we find the following: "Objectivism holds that the essence of a concept is that fundamental characteristic(s) upon which the greatest number of other characteristics depend."
This doctrine implies that essences are "metaphysical" in some sort of quasi-Aristolean fashion. Rand confronts us with an equation of sorts. The fundamental characteristic is that upon which the greatest number of other characteristic depend and that which makes the greatest number possible. Rand goes on to describe this fundamental characteristic as metaphysical and as the "essence of a concept." In other words: fundamental characteristic = that which makes the greatest number of others possible = essence. If so, why then does Rand insist that essences are epistemological? Her actual doctrine, as expounded in IOTE, implies that essences are in fact "metaphysical" in a quasi-Aristolean sense.
Per usual, Rand is trying to have it both ways. She wants to embrace the Aristotlean view of essences and definitions without getting drawn into the Platonic implications of the doctrine. However, this is just not possible. The Aristotlean view of definitions and their role in cognition implies a metaphysical outlook that is at odds with science and reality. Worse, it encourages just the sort of rationalistic type of thinking and arguing that leads to a sterile scholasticism. In Objectivism, this sort of scholasticism is called "thinking by essentials," and will serve as the topic for my next post.