human machine contains an almost infinite number of organs, and that it is
continually exposed to the shock of the bodies that surround it,[1] and
which by an innumerable variety of shakings produce in it a thousand sorts
of modifications. How is it possible to conceive that this _pre-established
harmony_ should never be disordered, but go on still during the longest
life of a man, notwithstanding the infinite varieties of the reciprocal
action of so many organs upon one another, which are surrounded on all
sides with infinite corpuscles, sometimes hot and sometimes cold, sometimes
dry and sometimes moist, and always acting, and pricking the nerves a
thousand different ways? Suppose that the multiplicity of organs and of
external agents be a necessary instrument of the almost infinite variety of
changes in a human body: will that variety have the exactness here
required? Will it never disturb the correspondence of those changes with
the changes of the soul? This seems to be altogether impossible.

[1] 'According to M. Leibniz what is active in every substance ought to be
reduced to a true unity. Since therefore the body of every man is composed
of several substances, each of them ought to have a principle of action
really distinct from the principle of each of the others. He will have the
action of every principle to be spontaneous. Now this must vary the effects
_ad infinitum_, and confound them. For the impression of the neighbouring
bodies must needs put some constraint upon the natural spontaneity of every
one of them.'

'IV. It is in vain to have recourse to the power of God, in order to
maintain that brutes are mere machines; it is in vain to say that God was
able to make machines so artfully contrived that the voice of a man, the
reflected light of an object, etc., will strike them exactly where it is
necessary, that they may move in a given manner. This supposition is
rejected by everybody except some Cartesians; and no Cartesian would admit