Economics is a “social science,” meaning that it studies people and aspects of society. Other social sciences include psychology, sociology, and anthropology. The natural sciences, on the other hand, study aspects of the natural world. The natural sciences include physics, chemistry, biology, astronomy, and meteorology.
Because of their different subject matter, the social sciences focus on purposeful action, as described in the preceding section, while the natural sciences focus on mindless behavior. Even though he might not even be aware that he is doing it, the social scientist’s explanations and theories at least implicitly rely on the hypothesis that there are other minds at work, influencing events. In sharp contrast, with the notable exception of biology, the natural scientist typically doesn’t refer to a conscious intelligence when explaining events in his field of expertise.
This awareness of other minds, and the fact that other thinking humans have their individual motivations, pervades the social sciences. It’s not confined to the formation of theories to explain events, either: Even the raw “facts” of the social sciences are themselves mental things, and not purely natural or physical. For example, a sociologist might come up with a theory relating an increase in the crime rate with the increase in the rate of divorce. But in order for the sociologist to even collect data to test this theory, she needs to “get inside other people’s minds” in order to know which events should be classified as crimes and divorces in the first place; these are not mere brute facts of nature.
Even the “Facts” of the Social Sciences Are Related to the Mind
Take such things as tools, food, medicine, weapons, words, sentences, communications, and acts of production.... I believe these to be fair samples of the kind of objects of human activity which constantly occur in the social sciences. It is easily seen that all these concepts... refer not to some objective properties possessed by the things, or which the observer can find out about them, but to views which some other person holds about the things. These objects cannot even be defined in physical terms, because there is no single physical property which any one member of a class must possess.... [T]hey can be defined only by indicating relations between three terms: a purpose, somebody who holds that purpose, and an object which that person thinks to be a suitable means for that purpose.
—Friedrich A. Hayek, Individualism and Economic Order (Chicago: University of Chicago Press, 1948), pp. 59–60
For example, if Sally runs her car over Joe and he dies, this may or may not count as a homicide. If Sally had a heart attack five seconds before the crash, it was probably not a crime, but rather just an accident. On the other hand, if the cops arrive at the scene to hear Sally yelling, “That’s the last time you’ll cheat on me!” then it’s time to read Sally her rights. Notice that ultimately it is Sally’s mind that makes the difference; the sociologist needs to make guesses about what Sally consciously intended in order to know if a crime occurred. No amount of physical description per se can decide the matter, except insofar as the description sheds light on what Sally was thinking when the car struck Joe. Her mental will has the power to transform a regular car into a murder weapon. To stress the point one last time: Nothing physical changes in the composition of the car during this transformation; the physicist and chemist wouldn’t notice anything happening to the molecules forming the car. On the contrary, when we say that Sally “turned the vehicle into a murder weapon,” we are rendering a judgment concerning the intangible, directly unobservable state of Sally’s mind. The physical movements of Sally’s hands and feet as she controlled the car are not the crucial issue; it is her conscious intentions that determine whether we need to add one more homicide to the running total.
As the example of Sally hitting Joe with her car illustrates, even the “raw facts” of the social sciences are tinged with our understanding of other people’s minds. In contrast, typically in the natural sciences neither the raw facts, nor the theories developed to explain them, rely on an appreciation of the intentions of other thinking beings. The natural scientist can look out upon the physical world and try to come up with explanations of its “mindless” behavior.