Routledge History of Philosophy Volume IV

Physics
GASSENDI AND HOBBES 231
Gassendi’s physics begins with questions about the number of worlds, the
existence of the world-soul and the known locations of the known parts of the
world. This helps to define in a preliminary way the scheme of nature that
physics is concerned with. He goes on to consider the metaphysical status of
place and time. From Galileo’s results concerning falling bodies he knew that
physical effects could be a function of elapsed time or space traversed, and yet
none of the traditional categories for real things—substance, attribute, corporeal
or incorporeal —seemed to classify place and time adequately: Gassendi opens his
physics with reasons why the traditional categories are unsuitable and reasons
why place and space and duration are real and similar in their incorporeal
natures. He then tries to play down his evident departure from Aristotelian
physics by saying that what he calls space is just the same as ‘that space which is
generally called imaginary and which the majority of sacred doctors admit exists
beyond the universe’ (Book II, ch. 1, Brush, 389). By ‘imaginary’ he does not
mean fictional. Rather, as he explains, he means something that it takes
imagination, and in particular the power the imagination has of constructing
analogues of the space it senses, to conceive. The power of making analogues
is mentioned in Part One of Institutio Logica (canon 3) and consists of forming a
likeness to something borne in by the senses.
Section One of the physics continues with the exposition of a number of
competing theories of the nature of the matter of the universe, culminating in the
acceptance of a revised Epicurean atomism in Book III, ch. 8. The chapter starts
with a list of departures from Epicurus. Although Gassendi agrees that ‘the
matter of the world and of all the things in it is made up of atoms’ (Brush, 398),
he denies all of the following: that the atoms are eternal; that they are uncreated;
that they are infinite in number, capable of being any shape, and self-moving
(ibid., 399). He claims instead that ‘atoms are the primary form of matter, which
God created finite from the beginning, which he formed into this visible world,
which, finally, he ordained and permitted to undergo transformations out of
which, in short, all the bodies which exist in the universe are composed ’ (ibid.,
399).
He conceives matter not in Cartesian fashion as extension in three dimensions
simply, but as solid or offering resistance. Atoms are indivisible particles of
matter. To the question of whether a physical indivisible is conceivable, given
that whatever is physical would seem to have parts, Gassendi generally replies by
drawing an analogy between a physical minimum and minimum sensible.
Something so small as to be at the limit of what the human eye can register—
Gassendi’s example is the itch mite—can nevertheless be conceived to have a
surface made up of indefinitely many physical parts—atoms, say. This does not
take away its claim to be the smallest visible thing; similarly, the fact that it is
possible to think of the atom’s extremities matched one to one with indefinitely
many geometrical points does not take away its status as the smallest physical