The Fruitful Facets of Galton's Polyhedron 349
and internally mediated. The public carriages of London take discrete forms as
omnibuses, hansoms, and four-wheelers. All these forms can be improved, but the
boundaries of the types seem inviolable, for "the old familiar patterns cannot, as it
thus far appears, be changed with advantage, taking the circumstances of London
as they are." (Galton, obviously, did not anticipate the macromutation of the
internal combustion engine!) The three "islands" arose as discontinuous inventions
and cannot be transformed one into the other, for intermediary steps would be
structurally inviable: "A useful blend between a four-wheeler and a hansom would
be impossible; it would have to run on three wheels and the half-way position for
the driver would be upon its roof" (1889, p. 31). (In the old hansom, or two-
wheeled cab, the driver sat on an elevated platform behind the passenger cabin, and
reins to the horses ran over the roof. Drivers of four-wheeled cabs sat in front.)
- The positions of stability, for both subtypes (discontinuities within species)
and types, are not honed by natural selection, but internally preset as rare
configurations of coherence among parts. The causal basis of stable form must
therefore be explained by internal integrity, not by adaptation.
In his first formulation (1869, 1884 edition, p. 370), Galton proposed an
internal, correlational basis for morphological stability: "It is easy to form a
general idea of the conditions of stable equilibrium in the organic world where one
element is so correlated with another that there must be an enormous number of
unstable combinations for each that is capable of maintaining itself unchanged,
generation after generation."
As his most enduring practical legacy, Galton (1892) pioneered the use of
fingerprints in identification and criminology. He also found in these "papillary
ridges" an ideal example of discontinuous stable "islands" (subtypes in this case)
that could not be attributed to direct natural selection. Galton extols the value of
these patterns as stable and traceable throughout ontogeny: "We know nothing by
observation about the persistence of any internal character, because it is not
feasible to dissect a man in his boyhood, and a second or third time in his after life,
whereas finger prints can be taken as often as desired" (1894, p. 366).
Fingerprints serve as ideal examples of internally generated structural islands
for "they fall into three definite and widely different classes... transitional forms
between them being rare and the typical forms being frequent, while the frequency
of deviations from the several typical centers... correspond approximately with
the normal law of frequency" (1894, pp. 366-367). Individual patterns remain
stable throughout life "and are consequently not unimportant in spite of their
minute character" (p. 366).
Nonetheless, the stabilization of these three typical forms cannot be attributed
to natural selection:
Notwithstanding the early appearance of the patterns in fetal life and their
apparent importance, they are totally independent of any quality upon
which either natural selection or marriage selection can be conceived to
depend. For example, I find the same general run of patterns in