Routledge History of Philosophy Volume IV

OCCASIONALISM 339
classes of bodily motions, the strength of the soul’s sentiment of the desired good
determines whether the effect happens according to the laws of motion or
according to those of soul-body union.
Does occasionalism have any merit as a philosophy of science? So long as one
focuses exclusively on the assignment of causal power to God, it seems that
occasionalism cuts off any serious attempt at causal explanation. For any
particular effect E, the answer to the question ‘What produced E?’ is always the
same, namely God. But there is more to causal explanation than citing the
productive cause—even for an occasionalist. A causal explanation of a particular
effect must show why this effect occurred rather than some other. Such an
explanation has not been provided if the explanans works equally well for
anything else that might have happened instead. Suppose one wants to know why
linen dries when it is placed near the fire.
I shall not be a philosopher [Malebranche says] if I answer that God wills
it; for one knows well enough that all that happens, happens because God
wills it. One does not ask for the general cause, but for the particular cause
of a particular effect. I ought therefore to say that the small parts of the fire
or of the agitated wood, hitting against the linen, communicate their motion
to the parts of water on it, and detach them from the linen; and then I shall
have given the particular cause of a particular effect. 110
Instead of closing the door to scientific investigation of the causes of natural
events, occasionalism clarifies the topic of inquiry; one is looking not for causal
powers, but for conditions that determine the efficacy of natural laws.
Since all natural effects are produced by general volitions of God, and since
the general volitions that constitute the laws of nature are discoverable by reason
and experience, every part of the natural world is in principle amenable to
scientific inquiry. Malebranche offers little hope for a science of mind; for he
insists that we know our own minds only through our inner feeling of what takes
place in us, and other minds only by analogy with our own. 111 He does, however,
lay the foundation for an empirical science of human behaviour. According to
Cartesian doctrine, animal behaviour is ultimately explainable by the laws of
motion alone, whereas human behaviour is not. For Malebranche, human
behaviour is explainable by a judicious combination of the laws of motion with
those of soul-body union.
There are affinities between the mechanisms of animal and human behaviour.
In both animals and humans, there is a natural connection between brain traces
and the motion of the animal spirits. Different patterns of behaviour are
associated with different brain traces. There are two kinds of brain traces: natural
and acquired. Natural traces are common to all members of a species and can
never be completely destroyed. Acquired traces are gradually lost unless they are
reinforced by continual application of the conditions that originally gave rise to
them. When acquired traces incline an individual toward behaviour contrary to