34 ° THE MISMEASURE OF MAN
always demonstrate that a general factor exists; using the latter, we could
almost always demonstrate, even with the same set of data, that it does not
exist (Burt, 1940, pp. 27-28).
But didn't Burt and Spearman understand that this very
defense constituted their own undoing as well as Thurstone's?
They were right, undeniably right. Thurstone had not proven an
alternate reality. He had begun from different assumptions about
the structure of mind and invented a mathematical scheme more
in accord with his preferences. But the same criticism applies with
equal force to Spearman and Burt. They too had started with an
assumption about the nature of intelligence and had devised a
mathematical system to buttress it. If the same data can be fit into
two such different mathematical schemes, how can we say with
assurance that one represents reality and the other a diversionary
tinkering? Perhaps both views of reality are wrong, and their
mutual failure lies in their common error: a shared belief in the
reification of factors.
Copernicus was right, even though acceptable tables of plane-
tary positions can be generated from Ptolemy's system. Burt and
Spearman might be right even though Thurstone's mathematics
treats the same data with equal facility. To vindicate either view,
some legitimate appeal must be made outside the abstract mathe-
matics itself. In this case, some biological grounding must be dis-
covered. If biochemists had ever found Spearman's cerebral
energy, if neurologists had ever mapped Thurstone's PMA's to
definite areas of the cerebral cortex, then the basis for a preference
might have been established. All combatants made appeals to biol-
ogy and advanced tenuous claims, but no concrete tie has even
been confirmed between any neurological object and a factor axis.
We are left only with the mathematics, and therefore cannot
validate either system. Both are plagued with the conceptual error
of reification. Factor analysis is a fine descriptive tool; I do not
think that it will uncover the elusive (and illusory) factors, or vec-
tors, of mind. Thurstone dethroned g not by being right with his
alternate system, but by being equally wrong—and thus exposing
the methodological errors of the entire enterprise.*
*Tuddenham (1962, p. 516) writes: "Test constructors will continue to employ fac-
torial procedures, provided they pay off in improving the efficiency and predictive
value of our test batteries, but the hope that factor analysis can supply a short inven-