The Mismeasure of Man

We pass through this world but once. Few tragedies can be more extensive than the stunting of life, few injustices deeper than the denial of an opportunity to strive or even to hope, by a limit imposed from without, but falsely identified as lying within.

Errors of reductionism and biodeterminism take over in such silly statements as “Intelligence is 60 percent genetic and 40 percent environmental.” A 60 percent (or whatever) “heritability” for intelligence means no such thing. We shall not get this issue straight until we realize that the “interactionism” we all accept does not permit such statements as “Trait x is 29 percent environmental and 71 percent genetic.” When causative factors (more than two, by the way) interact so complexly, and throughout growth, to produce an intricate adult being, we cannot, in principle, parse that being’s behavior into quantitative percentages of remote root causes. The adult being is an emergent entity who must be understood at his own level and in his own totality. The truly salient issues are malleability and flexibility, not fallacious parsing by percentages. A trait may be 90 percent heritable, yet entirely malleable.

science must be understood as a social phenomenon, a gutsy, human enterprise, not the work of robots programed to collect pure information.

Duke est desipere in loco [it is pleasant to act foolishly from time to time—a line from Horace].

The Mismeasure of Man treats one particular form of quantified claim about the ranking of human groups: the argument that intelligence can be meaningfully abstracted as a single number capable of ranking all people on a linear scale of intrinsic and unalterable mental worth. Fortunately—and I made my decision on purpose—this limited subject embodies the deepest (and most common) philosophical error, with the most fundamental and far-ranging social impact, for the entire troubling subject of nature and nurture, or the genetic contribution to human social organization.

self-deception as the preliminary to public deception is almost automatic. —WALTER LIPPMANN,