As Damnier (1942, pp. 372, 470-477), in his history of science, noted, the impact of the new wave-mechanics and quantum theory on physics has disrupted the deterministic argument at its very foundation in the physical sciences. Ledger Wood (1957, p. 311) indicates that: “If there is a real indeterminacy at the subatomic level of quantum mechanics, this affords at least the possibility of the physiological and ultimately the psychological indeterminacy which constitutes the freedom of the will.” Not all psychologists, however, have accepted the principle of psychic indeterminacy as proof of free-will. The law of probability does not refute the determinism of psychic phenomena, for there are psychic phenomena which should be considered determined even though the determining factors are so far beyond our understanding at the time as to compel us to describe the phenomenon in terms of probability.

Over the years, Lillie (1927, pp. 167-185) and Cattell (1950) noted that the behavior of human beings can in fact be predicted via statistical operations by studying a large number of people. This is what is now commonly called the nomothetic stance regarding knowledge: we can “know” in large quantities via equitable sampling of the phenomenon being sampled. However, the human being as an isolated individual cannot be considered determined, for this person is inaccessible to the tools of statistics and probability. This is the ideographic stance: we can only “know” with regard to the study of a single individual’s history and behavior as this individual is located in a specific situation.

Lillie points out that the physicist, in considering the behavior of the atom, is working with a great number of these entities and is determining the “statistical regularity” of the atoms’ behavior. He must consider a. great many atoms in order to be able to accurately predict the movement of any one of them. There would thus seem to be no room for the study of the isolated individual—a study which Skinner (1959) and many others believe to be highly valuable in a deterministic system, unless like Freud we wish to make highly speculative generalizations about human behavior.

Empirical Verification argument

Many years ago, Mercier (1944, pp. 252-261) speculated that an empirical justification for the free-will position could be posed. He states that if freedom of the will can be defined as the capacity to conceive universals, and apply these universals to choices of behavior, then the freedom of the will can be empirically studied via the study of case histories in which universals are employed.

Mercier seems to be appealing to the same introspective data as characterized the free-will argument, yet he proposes that the study of case histories might be a more useful way to approach the issue, Certainly, a study of the way in which people make use of general constructs or universals would be valuable, but it is hard to see how this would prove anything more than that the human being can abstract and employee abstract concepts in the process of evaluation and decision-making,

There are two very important schools of psychology which generally adopt a free-will position: ego-psychology and existential psychology. They do not align easily with any of the four fundamental arguments. In concluding this discussion of free-will, I will briefly consider the perspectives presented by each of these two schools.