Hereditarianism - Competing Theories

Competing Theories

Theories opposed to hereditarianism include behaviorism, social determinism and environmental determinism. This disagreement and controversy is part of the nature versus nurture debate. Hereditarianism is almost universally supported when used to explain physical differences such as skin color, and in the post World War II era, almost universally rejected when used to explain psychometric differences, particularly IQ.

Hereditarianism is sometimes used as a synonym for biological or genetic determinism, though some scholars distinguish the two terms. When distinguished, biological determinism is used to mean that heredity is the only factor. Supporters of hereditarianism reject this sense of biological determinism for most cases. However, in some cases genetic determinism is true; for example, Matt Ridley describes Huntington's disease as "pure fatalism, undiluted by environmental variability." In other cases, hereditarians would see no role for genes; for example, the condition of "not knowing a word of Chinese" has nothing to do (directly) with genes. In individual cases, hereditarians believe that genes play an intermediate role, while genes largely determine the differences between the human races and genders. In all cases, they believe this is an empirical and not a philosophical question.

Some scholars argue that an organism inherits only alleles, and that only the interaction of alleles with environment creates phenotypes. Put another way, in this view there are no additive genetic or environmental effects, only interactions. Steven Pinker has criticized this view, which he terms "holistic interactionism". Philosopher Daniel Dennett satirized this view: "Surely 'everyone knows' that the nature-nurture debate was resolved long ago, and neither side wins since everything-is-a-mixture-of-both-and-it's-all-very-complicated, so let's think of something else, right?" The hereditarian view is that for a set of actual people (i.e., a given set of genes and environments) it is possible to partition the causal influences between genetic and environmental variation.