’V.  Now let us consider the soul of Julius Caesar, and we shall find the thing more impossible still.  That soul was in the world without being exposed to the influence of any spirit.  The power it received from God was the only principle of the actions it produced at every moment:  and if those actions were different one from another, it was not because some of them were produced by the united influence of some springs which did not contribute to the production of others, for the soul of man is simple, indivisible and immaterial.  M. Leibniz owns it; and if he did not acknowledge it, but if, on the contrary, he should suppose with most philosophers and some of the most excellent metaphysicians of our age (Mr. Locke, for instance) that a compound of several material parts placed and disposed in a certain manner, is capable of thinking, his hypothesis would appear to be on that very ground absolutely impossible, and I could refute it several other ways; which I need not mention since he acknowledges the immateriality of our soul and builds upon it.

’Let us return to the soul of Julius Caesar, and call it an immaterial automaton (M.  Leibniz’s own phrase), and compare it with an atom of Epicurus; I mean an atom surrounded with a vacuum on all sides, and which will never meet any other atom.  This is a very just comparison:  for this atom, on the one hand, has a natural power of moving itself and exerts it without any assistance, and without being retarded or hindered by anything:  and, on the other hand, the soul of Caesar is a spirit which has received the faculty of producing thoughts, and exerts it without the influence [42] of any other spirit or of any body.  It is neither assisted nor thwarted by anything whatsoever.  If you consult the common notions and the ideas of order, you will find that this atom can never stop, and that having been in motion in the foregoing moment, it will continue in it at the present moment and in all the moments that shall follow, and that it will always move in the same manner.  This is the consequence of an axiom approved by M. Leibniz:  since a thing does always remain in the same state wherein it happens to be, unless it receives some alteration from some other thing ... we conclude, says he, not only that a body which is at rest will always be at rest, but that a body in motion will always keep that motion or change, that is, the same swiftness and the same direction, unless something happens to hinder it. (M.  Leibniz, ibid.)

’Everyone clearly sees that this atom, whether it moves by an innate power, as Democritus and Epicurus would have it, or by a power received from the Creator, will always move in the same line equally and after a uniform manner, without ever turning or going back.  Epicurus was laughed at, when he invented the motion of declination; it was a needless supposition, which he wanted in order to get out of the labyrinth of a fatal necessity; and he could give no reason for this