Criminality, Heredity, and Environment

Abstract

It is a curious fact that in science we often find a pendulumlike swing from one theory to another and then back again. Huygens’s wave theory of light was replaced by Newton’s corpuscular theory; this in turn was found to be defective and Young, Fresnel, and others replaced it with a new wave theory. In modern times, physicists found that light had characteristics of both wavelike and corpusclelike nature, and the later theories attempt to combine both properties. Similarly, as far as criminality and personality are concerned, the strong hereditarian theories of the 19th century were followed by equally strong environmentalist theories in the middle years of this century, and it is only in recent years that the realization has set in that both heredity and environment exert a causal influence in this field and that mathematical models have become available to help us break down the total phenotypic variance into components that can be quantatively estimated.