592 GOTTFRIEDLEIBNIZ
Hence it can be said in a manner of speaking and in a sense that is good, though remote
from ordinary usage that a particular substance never acts on another particular sub-
stance and is not acted upon by another either. This follows if we remember that what
happens to each is only a consequence of its idea or complete notion alone, since that
idea already includes all the predicates or events, and expresses the whole universe.
Indeed, nothing can happen to us but thoughts and perceptions, and all our thoughts and
our future perceptions are no more than consequences, albeit contingent, of our previ-
ous thoughts and perceptions. Hence, if I were capable of considering distinctly every-
thing happening or appearing to me at the present time, I would be able to see therein
everything that would ever happen or appear to me. This would not fail, but would hap-
pen in any case, if everything outside me were destroyed and only God and myself
remained. But as we attribute to other things, as if to causes acting on us, what we
perceive in some way in other things, we have to consider the basis of this judgement,
and what truth there is in it.
It is above all agreed that if we desire some phenomenon to happen at a certain
time and it occurs in the ordinary course of things, we say that we acted and that we
were the cause of it, as when I want to, as we say, “move my hand.” Also, when it seems
to me that by my will something happens to what I call another substance (and that this
is the way it would happen as I judge from frequent observation) although it was not
willed by it, I judge that this substance is acted upon. I admit this of myself when some-
thing happens to me in accordance with the will of another substance. Also, when we
will something to happen, and something else follows from it that we did not want, we
still say that we did it, provided that we understood how it followed. There are also
some phenomena of extension that we attribute to ourselves more particularly and
which have their basis a parte reiin what is called our body. As everything of impor-
tance happening to it (i.e. all the notable changes appearing to us in it) make themselves
strongly felt in it, ordinarily at least, we attribute all the passions to this body to our-
selves. We do so with very good reason, for even if we did not perceive them at the time,
we do not fail to become well aware of the consequences, just as if we had been trans-
ported from one place to another while asleep. We also attribute to ourselves the actions
of this body, as when we run, hit or fall, and when our body, continuing the motion once
begun, has some effect. But I do not attribute to myself what happens to other bodies,
because I realise that great changes can happen that I cannot perceive, unless my body
is exposed to them in a way I conceive appropriate to that assumption.
So it is quite clear that although all the bodies of the universe belong to us in some
way and harmonise with ours, we do not attribute to ourselves what happens to them.
For when my body is pushed, I say that I myself have been pushed, but if someone else
is pushed, I do not say that I have been pushed, even though I may perceive it and some
passion in me may arise from it, since I measure where I am by the place my body is in.
And this language is highly reasonable because it is appropriate for clear expression in
everyday practice. As for the mind, it can be said briefly that our acts of will and judge-
ments or reasonings are actions while our perceptions or sensations are passions. As for
the body, we say that a change that happens to it is an action when it follows from a
previous change, but otherwise it is a passion.
In general, to give our terms a meaning that reconciles metaphysics with practice,
it can be said that when several powers are affected by the same change the one that
passes to a higher degree of perfection or continues in the same acts, while the one that
immediately becomes more limited thereby, so that its expressions become more con-
fused, is acted upon.