Argyll, however, affirms that the "law of gravitation" as
put forth by Newton was something more than the statement of an
observed order. He admits that Kepler's three laws "were an observed
order of facts and nothing more." As to the law of gravitation, "it
contains an element which Kepler's laws did not contain, even an
element of causation, the recognition of which belongs to a higher
category of intellectual conceptions than that which is concerned in
the mere observation and record of separate and apparently unconnected
facts." There is hardly a line in these paragraphs which appears to me
to be indisputable. But, to confine myself to the matter in hand, I
cannot conceive that any one who had taken ordinary pains to acquaint
himself with the real nature of either Kepler's or Newton's work could
have written them. That the labours of Kepler, of all men in the
world, should be called "mere observation and record," is truly
wonderful. And any one who will look into the "Principia," or the
"Optics," or the "Letters to Bentley," will see, even if he has no
more special knowledge of the topics discussed than I have, that
Newton over and over again insisted that he had nothing to do with
gravitation as a physical cause, and that when he used the terms
attraction, force, and the like, he employed them, as he says,
"_mathematice_" and not "_physice_."

How these attractions [of gravity, magnetism, and
electricity] may be performed, I do not here consider. What
I call attraction may be performed by impulse or by some
other means unknown to me. I use that word here to signify
only in a general way any force by which bodies tend towards
one another, whatever be the cause.[26]

According to my reading of the best authorities upon the history of
science, Newton discovered neither gravitation, nor the law of
gravitation; nor did he pretend to offer more than a conjecture as to
the causation of gravitation. Moreover, his assertion that the notion
of a body acting where it is not, is one that no competent thinker
could entertain, is antagonistic to the whole current conception of
attractive and repulsive forces, and therefore of "the attractive
force of gravitation." What, then, was that labour of unsurpassed
magnitude and excellence and of immortal influence which Newton did
perform? In the first place, Newton defined the laws, rules, or
observed order of the phenomena of motion, which come under ou