'Fancy to yourself an animal created by God and designed to sing
continually. It will always sing, that is most certain; but if God designs
him a certain tablature, he must necessarily either put it before his eyes
or imprint it upon his memory or dispose his muscles in such a manner that
according to the laws of mechanism one certain note will always come after
another, agreeably to the order of the tablature. Without this one cannot
apprehend that the animal can always follow the whole set of the notes [45]
appointed him by God. Let us apply this to man's soul. M. Leibniz will have
it that it has received not only the power of producing thoughts
continually, but also the faculty of following always a certain set of
thoughts, which answers the continual changes that happen in the machine of
the body. This set of thoughts is like the tablature prescribed to the
singing animal above mentioned. Can the soul change its perceptions or
modifications at every moment according to such a set of thoughts, without
knowing the series of the notes, and actually thinking upon them? But
experience teaches us that it knows nothing of it. Were it not at least
necessary that in default of such a knowledge, there should be in the soul
a set of particular instruments, each of which would be a necessary cause
of such and such a thought? Must they not be so placed and disposed as to
operate precisely one after another, according to the correspondence
_pre-established_ between the changes of the body and the thoughts of the
soul? but it is most certain that an immaterial simple and indivisible
substance cannot be made up of such an innumerable multitude of particular
instruments placed one before another, according to the order of the
tablature in question. It is not therefore possible that a human soul
should execute that law.

'M. Leibniz supposes that the soul does not distinctly know its future
perceptions, _but that it perceives them confusedly_, and that _there are