Routledge History of Philosophy Volume IV

RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM 105
wishes to turn the whole of astronomy upside down. Even in those things
that are thrown into disorder I believe the Holy Scriptures, for Joshua
commanded the Sun to stand still, and not the Earth. 18
Among professional astronomers the work was greatly admired, but for its
astronomy, not its physics. A characteristic posture was to adopt what Robert
S.Westman 19 has called the Wittenberg interpretation of the theory: to take a
connoisseur’s delight in Copernicus’s mathematical techniques and employ them
about the astronomer’s proper business, such as the construction of tables, but to
reject as utterly mistaken the idea of a moving Earth. Paradoxically this
instrumentalist outlook received support from Copernicus’s own volume, for
Andreas Osiander, the Lutheran pastor who saw it through the press, inserted an
anonymous preface, possibly to ward off theological criticisms, which gave a low
truth status to astronomical theories.
It is proper to an astronomer to bring together the history of the celestial
motions by careful and skilful observation, and then to think up and invent
such causes for them, or hypotheses (since he can by no reasoning attain
the true causes), by which being assumed their motions can be correctly
calculated from the principles of geometry for the future as well as for the
past. The present author has eminently excelled in both these tasks, for it is
not necessary that the hypotheses be true nor indeed probable, but this one
thing suffices, that they exhibit an account (calculus) consistent with the
observations. 20
And some careless readers of the work were misled into thinking that this was
Copernicus’s own view.
Instrumentalism has rarely been a satisfactory psychological stance for
working scientists, and so it is not surprising that soon schemes were brought
forward that gave a more realist slant to the Wittenberg interpretation. The most
famous of these, and one which he guarded jealously as his very own intellectual
property, was by the great Danish astronomer Tycho Brahe. In this the Moon and
the Sun orbited the stationary Earth, while the other planets circled the Sun and
accompanied it on its annual journey about the Earth. This had all the
astronomical advantages of the Copernican system and none of what were
perceived as its physical disadvantages. It also had no need to accommodate the
fact that no parallax (apparent relative motion among the fixed stars) had been
observed, which would have been expected if the Earth were moving. Tycho laid
particular emphasis on this difficulty for Copernicanism, and calculated that, if
the Earth were moving, then even a star that had only a moderate apparent size
would have to be so far away that it would in fact be as big as the whole of the
Earth’s orbit. Not surprisingly, when Copernicanism came under ecclesiastical
fire, the Tychonic compromise emerged as the favourite system of the Jesuits,
who were themselves strong pioneers of scientific advance.