download

SCIENCE 587
fication, Grosseteste assumed the principle ofthe uniformity of
nature, and was guided in his choice of possible theories by
the principle of economy. An important philosophical con/
sequence of his logical analysis was his conclusion that
scientific theories are at best probable, and not necessarily true.
His understanding of these matters established the methods
and interpretations ofscience developed by his successors both
in Oxford and abroad.
Grosseteste's interest in optics was directly related to his
second contribution to the scientific methods of his time. For
two reasons, one methodological and the other metaphysical, he
held that methematics was essential for a scientific understand'
ing of the physical world. The method by which he used
mathematics for this
purpose was Aristotle's
principle
of'sub/
ordination*, according to which some physical sciences, for
example optics and astronomy, were logically subordinate to
a mathematical science, for example geometry, in the sense that
they used particular cases of general mathematical laws. Grosse/
teste held that mathematics could be used to describe wl?at
happened, for example the reflection and refraction of light and
the movements of the planets, but that the mathematical ex/
pressions did not reveal the physical cause ofthese optical and
astronomical laws, which was to be sought in the nature ofthe
substances involved. This distinction between mathematical
and physical laws, analogous to the modern distinction between
kinematics and dynamics, had been developed by Simplicius,
from whom Grosseteste undoubtedly learnt it.
Grosseteste's conception of the nature of fundamental
physical substance was a peculiar one which provided his
second reason for holding that mathematics was essential for
physical inquiry; he maintained that the fundamental physical
substance was a fundamental 'light* (lux\ not identical with,
but manifesting itself in, visible light. In a short treatise, De Luce,
he described how in the beginning God created formless
matter and a point of this fundamental light; this propagated
itself in a sphere and produced the dimensions of space, and
then, by^a complicated series of changes and interactions, the