THE REAL ERROR OF CYRIL BURT 337
inferiority—or of environmentalist goodies extolling the irreduci-
ble worth of all human beings. Other biases must be factored
(pardon the vernacular usage) into a complex equation. Heredi-
tarianism becomes an instrument for assigning groups to inferior-
ity only when combined with a belief in ranking and differential
worth. Burt united both views in his hereditarian synthesis. Thur-
stone exceeded Burt in his commitment to a naive form of reifica-
tion, and he did not oppose hereditarian claims (though he
certainly never pursued them with the single-minded vigor of a
Burt). But he chose not to rank and weigh on a single scale of
general merit, and his destruction of Burt's primary instrument of
ranking—Spearman's g—altered the history of mental testing.
Spearman and Burt react
When Thurstone dispersed g as an illusion, Spearman was still
alive and pugnacious as ever, while Burt was at the height of his
powers and influence. Spearman, who had deftly defended g for
thirty years by incorporating critics within his flexible system, real-
ized that Thurstone could not be so accommodated:
Hitherto all such attacks on it \g] appear to have eventually weakened
into mere attempts to explain it more simply. Now, however, there has
arisen a very different crisis; in a recent study, nothing has been found to
explain; the general factor has just vanished. Moreover, the said study is
no ordinary one. Alike for eminence of the author, for judiciousness of
plan, and for comprehensiveness of scope, it would be hard to find any
match for the very recent work on Primary Mental Abilities by L. L. Thur-
stone (Spearman, 1939, p. 78).Spearman admitted that g, as an average among tests, could
vary in position from battery to battery. But he held that its wan-
dering was minor in scope, and that it always pointed in the same
general direction, determined by the pervasive positive correlation
between tests. Thurstone had not eliminated g; he had merely
obscured it by a mathematical dodge, distributing it by bits and
pieces among a set of group factors: "The new operation consisted
essentially in scattering^ among such numerous group factors, that
the fragment assigned to each separately became too small to be
noticeable" (1939, p. 14).
Spearman then turned Thurstone's favorite argument against
him. As a convinced reifier, Thurstone believed that PMA's were