Cause Principle Unity

On magic
This philosophy is supreme, divine and true, since it is quite in agreement
with nature by positing the following principles of reality: first, water
or the abyss or the Styx; second, dryness or atoms or earth (I am not speaking
of the terrestrial globe); third, spirit or air or soul; fourth, light. These
are so different from each other that one cannot be transformed into the
nature of another, although they do come together and associate, sometimes
more or less, sometimes all or some of them.
On the double motion of things and on attraction
There are two kinds of motion, natural and preternatural. Natural motion
comes from an intrinsic principle, while preternatural motion is from an
extrinsic principle; natural motion is in harmony with the nature, structure
and generation of things, preternatural motion is not. The latter is
twofold: violent, which is against nature, and ordered or structured, which
is not contrary to nature. What is commonly called natural motion is found
in all genera or in all the categories, leaving out the distinction between
motion and mutation. 10
For now, we omit all the other classes of motion and their species and
consider only natural motion in place. One type of this is possessed by natural
things and does not move a thing away from it own proper place; this
is circular motion, or a version thereof. The other type is straight line
motion, which is not naturally possessed by natural things. For example,
air moves in a straight line to fill a void. A stone moves through air, and a
body which is heavier than water moves through water, in a straight line in
order to occupy the place in which it either is at rest or moves naturally.
And as much as it can, a contrary flees from its contrary in a straight line,
for example, fumes, vapour and water from fire (for it goes faster to a
greater distance through a straight line). Likewise, similar and agreeable
things tend towards each other in a straight line, for example, straw to
amber, and iron to a magnet, so that they can rest together or move better
and more easily.
There is also a third type of local motion, which is an inflow and an
outflow found in all natural things when any of their parts are ejected
in various ways and in every direction. For now, we will call this ‘spherical’
motion. For it does not occur either in a straight line, or to or from
10 This is an Aristotelian distinction in which ‘motion’ refers to changes in quality, quantity and place,
while ‘mutation’ refers to changes in substance or essence.
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