Some psychologists believe that human behavior is deter- mined but that the causes of behavior cannot be accurately measured. This belief mirrors Heisen- berg’s uncertainty principle. The German physicist Werner Karl Heisenberg (1901–1976) found that the very act of observing an electron influences its activity and casts doubt on the validity of the obser- vation. Heisenberg concluded that nothing can ever be known with certainty in science. Translated into psychology, this principle says that, although human behavior is indeed determined, we can never learn some causes of behavior, because in attempting to observe them we change them. In this way, the experimental setting itself may act as a confound- ing variable in the search for the causes of human behavior. Psychologists who accept this viewpoint believe that there are specific causes of behavior but that they cannot be accurately known. Such a position is called indeterminism. Another example of indeterminacy is Immanuel Kant’s (1724–1804) conclusion that a science of psychology is impos- sible because the mind could not be objectively employed to study itself. MacLeod (1975) summa- rized Kant’s position as follows:
Kant challenged the very basis of a science of psychology. If psychology is the study of “the mind,” and if every observation and every deduction is an operation of a mind which silently imposes its own categories seldom, if ever, caused by a single event or even a few events. Rather, a multitude of interacting events typically causes behavior. Second, some causes of behavior may be fortuitous. For example, a reluc- tant decision to attend a social event may result in meeting one’s future spouse. About such meet- ings Bandura (1982) says, “Chance encounters play a prominent role in shaping the course of human lives.”