darwin, design, and the unification of nature 169entific activity and religious sensibility to coexist even if the theology was some-
times bent in heterodox directions. Newton provides perhaps the best example
for testing a claim that unity principles might do real work in the sciences. In
exploring what the unity ofsciencemight mean, Ian Hacking has identified
three metaphysical theses that might find expression in scientific practice. One
is a thesis of interconnectedness, which he notes in some minds “is rooted in
a religious conception of the world and how God must have made it”—reli-
gious in the sense of the major monotheistic religions.^19 Newton would be an
exemplar through his connecting lunar and planetary orbits with terrestrial
gravitation. A second metaphysical thesis, which Hacking calls the structural,
refers to the unification achieved by subsuming laws of nature under those of
higher generality, which Newton would again illustrate through his explanation
of Kepler’s laws. Hacking’s third metaphysical thesis he describes as taxonomic
since it refers to the belief that there is “one fundamental, ultimate, right
system of classifying everything”.^20 Nature contains natural kinds. One of the
clearest examples of this principle in Newton would be his taxonomy of natural
forces. When in Query 31 of hisOptickshe referred to the attractions of gravity,
electricity, and magnetism, Newton added that “these Instances shew the Tenor
and Course of Nature, and make it not improbable but that there may be more
attractive powers than these. For Nature is very consonant and conformable to
herself.”^21 As has long been recognized, there was a dream here of quantifying
all of nature’s forces including the uncooperative one of chemical affinity.
There were times, too, when Newton would construct analogies between the
intervals of the musical scale, the optical spectrum and planetary distances,
seeking an overarching unity.^22
The consonance of Nature and the analogy of nature did do work for New-
ton. It would be difficult to deny that one of his arguments for the universality
of the laws of motion derived from his understanding of divine omnipresence:
“If there be an universal life and all space be the sensorium of a thinking being
who by immediate presence perceives all things in it...thelaws of motion
arising from life or will may be of universal extent.”^23 The God who perceived
everything was the God to whom Newton in his youth confessed such sins as
telling lies about a louse, eating an apple in the house of God, making a mouse-
trap on the Sabbath, and dreaming of burning down his mother’s house with
his stepfather in it!^24
The inverse move from the unity of nature to the unity of the godhead,
despite its circularity, was to prove extremely resilient in standard works of
natural theology. Devoting an entire chapter to the unity of the deity, William
Paley began it by declaring that there was proof in the uniformity of plan
observable in the universe. One principle of gravitation caused a stone to drop
toward the Earth and the moon to wheel around it. One law of attraction carried
all the planets about the Sun.^25 Paley was a bit worried by lobsters despite the
fact that the taste of good food was evidence of divine goodness. Their exterior