Cause Principle Unity

On magic
subject rather than another. For, although this cause and its causal power
always remain immutably the same, it produces contrary (and not just
different) effects in different subjects with the help of different types of
matter. As a result, there need be only one such simple, principal efficient
cause, like there is only one sun, one heat and one light, which by turning
forward or backward, by approaching and receding, mediately and immediately
causes the winter, the summer, and their different and contrary
weather, and the ordering of the seasons.
Matter is also derived from this same cause, if we wish to believe those
who think that the four commonly mentioned elements change into each
other. The originator of this view was Plato, who sometimes says that all
things were produced from one matter and one efficient cause. But whatever
may have been the method of production used by the first universal
cause, and whether one assumes only one or many material principles, any
human or spiritual secondary cause must recognize that, because of the
great multitude and variety of producing species, there are many types of
matter having act or form, through which a subject is able to influence
things outside of itself.
In regard to the powers or forms or accidents which are transmitted
from subject to subject, some are observable, for example, those that belong
to the genus of active and passive qualities, and the things that immediately
follow from them, like heating and cooling, wetting and drying, softening
and hardening, attracting and repelling. Others are more hidden because
their effects are also obscure, for example, to be happy or sad, to experience
desire or aversion, and fear or boldness. These are said to be caused
by external impressions acting on the cognitive power in humans and on
the estimative power in animals. Thus, when a child or infant sees a snake,
or when a sheep sees a wolf, it conceives an image, without any other
experience, of hostility and of fear of its own death or destruction.
The explanation of this is to be found in the internal sense, which is,
indeed, moved by the external impressions, although indirectly. For nature
gives not only existence to each species, but also the desire in each individual
to preserve itself in its present state. Thus, it implants in each thing an
internal spirit, or sense, if you prefer that word, by which as from an internal
dictate it recognizes and avoids great dangers. This can be seen not only
in the examples given above, but also in all things in which, even if they
seem to be defective or dead, there still resides a spirit striving with all its
power to conserve the present condition. This happens in falling drops
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