Routledge History of Philosophy Volume IV

104 SCIENCE AND MATHEMATICS UP TO DESCARTES
planets were conceived as attached or along which they moved. A causal and
harmonious structure for the universe was also theologically supported, for a
good Creator God would surely have proceeded according to a rational plan.
This attitude clearly lay behind Copernicus’s criticism of astronomers in the
Ptolemaic tradition for producing fine parts which could by no means be fitted
together in a tidy fashion.
It was with them exactly as if someone had taken from different places, in
no way mutually corresponding, hands, feet, head and other members, all
excellently depicted but not in relation to a single body, so that a monster
was composed from them rather than a man. 17
Copernicus’s own system as portrayed in the famous diagram included in
Chapter 10 of Book I of the De revolutionibus (with an accompanying panegyric
on the Sun) appears admirably simple and rational, but important cracks lie very
near to the surface. In the first place the system was obviously physical
nonsense. If the Earth is really moving with such huge speed, we should surely
experience it by such phenomena as constant high winds and stones that refused
to fall at the bottom of the towers from which they are dropped; also its whole
body should fly apart, like the materials on a potter’s wheel that is spun too fast.
Copernicus was not blind to such objections, and answered them in summary
fashion, but in terms which we may find easier to accept than did his own
contemporaries. And after all, was it worth destroying important foundations of
the well-tried edifice of Aristotelian physics at the behest of a mere astronomer?
All this relates to Book I of the De revolutionibus, understandably the only part
that is read by more than a few specialists in mathematical astronomy. But the
later five books destroy most of the simplicity of this book in order to make the
system work, that is, to ‘save the phenomena’, or provide a relatively good
predictive device for planetary positions, for in doing this Copernicus, although
rejecting the equant point, retained most of the techniques of earlier astronomy
for explaining the planetary movements by combinations of circular motions, and
in so doing produced a system that was arguably as complicated as Ptolemy’s.
This was not arrant conservatism but a natural use of procedures with which he
had been brought up, and which if rejected would almost certainly have
prevented him from doing any work worthy of serious astronomical recognition.
With these points made, the result is not surprising. The book did not fall on
dead ground, but neither did it win unconditional acclaim. Among the general
public it was seen to propose a pleasing or unpleasing paradox, perhaps
interesting for idle conversation, but only to be taken seriously by eccentrics or
fanatics. For instance, even before the book was published, Luther remarked
that,
Whoever wants to be clever must agree with nothing that others esteem.
He must do something of his own. This is what that fellow does who