In one sense, of course, we are. As I have several times had occasion to
remark, we are, in common life, justified in using words rather loosely,
provided that it is convenient to do so, and that it does not give rise
to misunderstandings.

But, in a stricter sense, we are not justified in thus speaking, for in
doing so we are carrying over into the sphere of the merely physical a
distinction which does not properly belong there, but has its place in
another realm. The student of mechanics tells us that the second ball
has affected the first quite as much as the first has affected the
second. We cannot simply regard the first as cause and the second as
effect, nor may we regard the motion of the first as cause and the
subsequent motion of the second as its effect alone. _The whole
situation at the one instant_--both balls, their relative positions and
their motion and rest--must be taken as the cause of _the whole situation
at the next instant_, and in this whole situation the condition of the
second ball has its place as well as that of the first.

If, then, we insist that to have causal efficiency is the same thing as
to be active, we should also admit that the second ball was active, and
quite as active as the first. It has certainly had as much to do with
the total result. But it offends us to speak of it in this way. We
prefer to say that the first was active and the second was acted upon.
What is the source of this distinction?

Its original source is to be found in the judgments we pass upon
conscious beings, bodies with minds; and it could never have been drawn
if men had not taken into consideration the relations of minds to the
changes in the physical world. As carried over to inanimate things it is
a transferred distinction; and its transference to this field is not
strictly justifiable, as has been indicated above.

I must make this clear by an illustration. I hurry along a street
towards the university, because the hour for my lecture is approaching.
I am struck down by a falling tile. In my advance up the street I am
regarded as active; in my fall to the ground I am regarded as passive.

Now, looking at both occurrences from the purely physical point of view,
we have nothing before us but a series of changes in the space relations
of certain masses of matter; and in all those changes both my body and
its environment are concerned. As I advance, my body cannot be regarded
as the sole cause of