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 the changes which are taking place.  My progress would be impossible without the aid of the ground upon which I tread.  Nor can I accuse the tile of being the sole cause of my demolition.  Had I not been what I was and where I was, the tile would have fallen in vain.  I must be regarded as a concurrent cause of my own disaster, and my unhappy state is attributable to me as truly as it is to the tile.

Why, then, am I in the one case regarded as active and in the other as passive?  In each case I am a cause of the result.  How does it happen that, in the first instance, I seem to most men to be the cause, and in the second to be not a cause at all?  The rapidity of my motion in the first instance cannot account for this judgment.  He who rides in the police van and he who is thrown from the car of a balloon may move with great rapidity and yet be regarded as passive.

Men speak as they do because they are not content to point out the physical antecedents of this and that occurrence and stop with that.  They recognize that, between my advance up the street and my fall to the ground there is one very important difference.  In the first case what is happening may be referred to an idea in my mind.  Were the idea not there, I should not do what I am doing.  In the second case, what has happened cannot be referred to an idea in my mind.