The number one issue with Rand's measurement omission hypothesis is that it attempts to solve an entirely irrelevant problem. It's a false solution to a false problem. Rand's "problem of universals" is a misnomer. Historically, the problem of universals dealt with whether universals were "real" (in the metaphysical sense). Rand deals with what might be called "the problem of Objectivist concepts." Rand introduces this issue as follows:
When we refer to three persons as "men," what do we designate by that term? The three persons are three individuals who differ in every particular respect and may not possess a single identical characteristic (not even their fingerprints). If you list all their particular characteristics, you will not find one representing manness. Where is the "manness" in men? What, in reality, corresponds to the concept "man" in our mind? [IOTE, 2]
Since Rand regards concept as the principle unit of human knowledge, the issue of how concepts "correspond" to reality becomes a problem. But what if we don't regard concepts as the principal unit of knowledge? What if we regard them merely as symbols conveying meanings? If a concept merely means what it means, then there's no issue of "validity" or correspondence at all. These meanings can be used to make assertions about anything, real or unreal, truth or lies. The merit of this approach is that it nips in the bud futile arguments about the meanings of words. What a word (or "concept") means is immaterial. It's the meaning of the statement that is important, and that meaning is whatever is intended by the individual who presents the statement. Once we understand the intended meaning of the statement, we can go about testing it to determine whether its true or false, plausible or implausible. By regarding concepts merely as meanings, rather than knowledge, we overstep altogether Rand's problem of universals and concepts. Instead of worrying about the relation of concepts to reality, we focus on the relation of our statements and theories to the real world. The problem of universals is replaced by the far more fruitful problem of theories. Testing and criticizing theories becomes our primary objective; while concepts merely become the vehicle for expressing our theories.
Now some might argue that regarding concepts as symbols conveying meanings does not in fact solve Rand's problem of Objectivist concepts; that it only moves it off a step further. Even as a symbol, the concept man does in fact refer to many different men. How does it do this?
If Objectivists insist on making it a problem, then it is a problem for them. It's not a problem for anyone else. Nearly everyone knows what you mean when you talk of "men." The problems confronting western civilization having nothing to do with the inability to provide a verbal solution to this issue. However, even if, for argument's sake, we were to grant that this is a legitimate problem, Rand has not provided a satisfying solution to this issue. Her so-called solution is no solution at all, but merely a retrenchment into the crude literalism of medieval scholasticism.
Here's how Rand "solves" what she misnamed the "problem of universals." She wanted to discover "how" concepts refer to in reality. To attain this end, she sought to describe in what ways the correspondence between concepts could be both literal and precise. From Rand's point of view, the concept could only be formed on the basis of all those characteristics shared by every referent subsumed by the concept. The concept man, for example, could not include, or refer to, the characteristic of irritability, because not all men are irritable. The concept also had to focus on "essential" characteristics, that is to say, characteristics which allowed a one class of objects to be differentiated from another similar class. All men have livers; but that characteristic is not essential, because other animals also have livers. The concept man must be formed on the basis of characteristics that are shared by all men. "Rationality," for example, is considered an essential characteristic of man, because, according to Rand, only men are "rational." One problem confronted the Objectivist view right from the start. Even if we were to grant (per implausible) that all men are rational (or "potentially" rational), it is plain from common observation that men are not all equally rational. Some are more and some are less rational, as Rand often reminded her readers. So in what way do men actually share the characteristic of rationality? How can the concept man be formed on the basis of a characteristics which exists in degrees (and sometimes only as a potentiality)? To explain this, Rand introduced her idea of measurement omission: "A concept," she declared, "is a mental integration of two or more units possessing the same distinguishing characteristic(s), with their particular measurements omitted."
This hypothesis, declared Rand, once and for all solves the "problem of universals." But note how it does so: by explaining what concepts literally refer to, in a narrow "identity" sense of reference. Rand is working out of a (tacit) paradigm that regards literalism as the highest mark of truth. She believes that she can solve the "problem of universals" by showing a literal identity between the concept and its referents. For Rand, concepts literally refer to the distinguishing characteristics of a particular class of objects, with the measurements omitted. Yet this desire to achieve a literal identity between concepts and referents is a false ideal. Concepts are symbols. They are not meant to be taken literally. They don't even constitute knowledge. Rand's phrase "conceptual knowledge" is a contradiction in terms. Symbols are not knowledge. They are items of description. Knowledge arises when the symbols are used to express statements describing matters of fact. Even if Rand (per impossible) had shown the literal identity of concepts with a given class of "units," this would have been merely a pyrrhic victory.
Even if concepts are symbols, doesn't the problem of classification remain? If symbols stand for multiple instances of a class of things, how are these classes formed? Even if Rand's measurement omission theory presented a false solution to a false problem, perhaps her theory actually applied to a different issue, i.e., the issue of classification. I will explore this topic in my next post.