Thursday, October 20, 2016

David Kelley’s View of the Measurement Omission Theory

A Theory of Abstraction
Dr. David Kelley

In my article on David Kelley’s The Contested Legacy of Ayn Rand I write that Kelley does not seem to be completely convinced about Ayn Rand’s theory of measurement omission for concept formation. I drew such an inference because in this book Kelley seems to suggest that it is possible that in future we may acquire evidence against the theory.

“As an inductive hypothesis about the functioning of a natural object—the human mind— the theory of measurement-omission is open to the possibility of revision in the same way that Newton’s theory of gravity was. And the same is true for the other principles of Objectivism.” (The Contested Legacy of Ayn Rand, Chapter: “Objectivism”)

Also, I have come across a few commentaries where the suggestion has been made that Kelley has doubts about the measurement omission theory.

But A Theory of Abstraction, the monograph that Kelley wrote in 1984, makes it clear that he has not rejected Ayn Rand's measurement omission theory. In fact, he clarifies on the page-6 that his purpose behind writing the monograph is to defend the theory of concepts that Rand has presented in her 1979 book Introduction to Objectivist Epistemology.

A Theory of Abstraction has solid arguments for supporting the measurement omission theory. Here’s an excerpt where he is talking about the second stage of concept formation:
“The differentiating aspect or moment is to distinguish the specific measurements of each object, in relation to the others, from the fact of commensurability. Since the determinacy of each object is seen as a matter of its quantitative relations to others, we abstract from determinacy by omitting or disregarding the specific measurements, and attending to each object merely qua unit. The integrating element of the process is the awareness of the dimension of similarity, the dimension along which the units are quantitatively related, as an attribute they share in different measure or degree. We are aware of the attribute as an axis on which each of the objects at hand, and an indefinite range of objects not present, can be given a place.” 
This is similar what Ayn Rand has said in her book Introduction to Objectivist Epistemology. She has defined a concept as “a mental integration of two or more units possessing the same distinguishing characteristic(s), with their particular measurements omitted.”

Further, Kelley says:
“The principle is only implicit in the way subjects attend to the units before them, and to the structure of relations they exhibit. It is implicit in the realization that the specific measurements can be disregarded, and that consequently any number of other objects, bearing any quantitative relation (within a certain range) to the units at hand, might be included in the group. In this way, the principle explains both the universality and the abstractness of the concept which results from the process. It should be noted, however, that after the concept is formed as a new mental unit, the principle does function as something like a rule, in two respects: the possession of the concept involves a kind of mental set or readiness to omit the measurements of new instances as they are encountered; and to omit the measurements of new dimensions of similarity among instances, as they are noticed.” 
In the final paragraph of the monograph, Kelley suggests that in future we may find a neurological explanation of the capacity for omitting measurements. Here’s the excerpt:
“If a concept is a distinct mental unit (and not merely a kind of collective mental name for an unintegrated set of particulars); if it is a way of regarding its instances as identical (not merely as similar), and thus of disregarding their specific measurements; then no matter how we decompose the process of concept-formation there must be a stage at which the awareness of determinate objects, qualities, and relations gives rise to an abstract awareness of them. For all the reasons given in the text, I think measurement-omission is that stage, and I do not see any way to decompose it further. Someday, perhaps, we will have a neurological explanation of the capacity for omitting measurements, and perhaps also an evolutionary explanation for our coming to have it. But I see no way to decompose it further into cognitive stages.”

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