As an evolutionary biologist and historian of science, Gould accepted "biological variability" (the premise of the transmission of intelligence via genetic heredity), but opposed "biological determinism", which posits that genes determine a definitive, unalterable social destiny for each man and each woman in life and society. "The Mismeasure of Man" is an analysis of statistical correlation, the mathematics applied by psychologists to establish the validity of IQ tests, and the heritability of intelligence. For example, to establish the validity of the proposition that IQ is supported by a general intelligence factor ("g" factor), the answers to several tests of cognitive ability must positively correlate; thus, for the "g" factor to be a heritable trait, the IQ-test scores of close-relation respondents must correlate more than the IQ-test scores of distant-relation respondents. However, correlation does not imply causation; for example, Gould said that the measures of the changes, over time, in "my age, the population of México, the price of Swiss cheese, my pet turtle’s weight, and the average distance between galaxies" have a high, positive correlation—yet that correlation does not indicate that Gould’s age increased because the Mexican population increased. More specifically, a high, positive correlation between the intelligence quotients of a parent and a child can be presumed either as evidence that IQ is genetically inherited, or that IQ is inherited through social and environmental factors. Moreover, because the data from IQ tests can be applied to arguing the logical validity of either proposition—genetic inheritance and environmental inheritance—the psychometric data have no inherent value.