Dump the Concept of Rationality Into the Deep Ocean

Abstract

I am professor of sociology who studied economics, and I am an advocate of the rational choice approach in sociology that applies the economic model of man to the explanation of phenomena that sociologists are interested in. Thus, I feel competent in dealing with the concept of rationality.

Let’s dump the concept of rationality. Already the definition of “rationality” is unclear.

I am professor of sociology who studied economics, and I am an advocate of the rational choice approach in sociology that applies the economic model of man to the explanation of phenomena that sociologists are interested in. Thus, I feel competent in dealing with the concept of rationality.

One might assume that a concept so pervasive not only in economics but in political science and philosophy as well is defined in a clear and consistent way. However, this is definitely not the case. A vast number of authors write about “rationality” without outlining what they mean. To be sure, many authors define the concept, but one finds dozens of meanings such as:

• 1. Rational = a person’s preferences are consistent (transitive, complete).

• 2. Rational = a person maximizes his or her objective utility (“objective” means “from the perspective of an observer”).

• 3. Rational = a person maximizes his or her subjective utility (“subjective” means “from the person’s perspective”).

• 4. Rational = a person deliberates before he or she acts.

• 5. Rational = a person is fully informed about the consequences of his or her behavior.

Which definition is appropriate then? Remember a basic fact of formal logic: a definition is a mere convention about how to use a concept. The previous examples are thus suggestions how to use the word “rational.” Such definitions do not say anything about the actual usage of a concept in everyday life. If authors wish to capture actual usage, they need empirical research. A definition does not capture the essence of a phenomenon either—whatever “essence” means. Because a (nominal) definition is not true or false, the criterion for accepting it is its usefulness. The question then is what the criteria are to judge the usefulness of a definition.

To what extent is one of those five definitions of “rational” useful? We do not know. I have never found an author who gives a detailed account of why he or she introduces a certain definition and not another one.

A definition is useful, among other things, if it is a shortcut for a long sentence and, thus, saves time and space. In the five frequently found definitions, the word “rational” is a shortcut for the expression to the right. In this particular case, using “rational” as the shortcut has also a disadvantage: the term has several nonscientific meanings, so the reader often associates other meanings than those stipulated in the definition. The question is then whether the gain of a shortcut is so high that taking into account possible misunderstandings is worthwhile.

To illustrate, why do we need the first definition of rational? We could simply speak of consistency—a term that needs definition as well and thus there is no gain in the abbreviation. The same holds for the second and third definition of rational: why not simply speak of objective or subjective utility maximization? And lastly, we don’t need the fourth or fifth definition either: one could simply speak of deliberation or “full information,” respectively, so that, again, there is no gain of the definition.

These examples suggest that using “rational” or “rationality” is not at all useful. It is even detrimental: the benefits of saving time or space are minimal and the costs are possible misunderstandings. Thus, forget about the concept of rationality. Try to avoid it—you’ll be surprised how easy this is.