The ego is placed at the brain terminals of the sensory nerves, and it receives messages which _flow in_; _i.e._ the clerk is actually placed in an exchange.
That the existence of the exchange is afterward denied in so many words does not mean that it has not played and does not continue to play an important part in the thought of the author.
It is interesting to see how a man of science, whose reflections compel him to deny the existence of the external world that we all seem to perceive and that we somehow recognize as distinct from anything in our minds, is _nevertheless compelled to admit the existence of this world at every turn_.
But if we do admit it, what shall we make of it?
Shall we deny the truth of what the psychologist has to tell us about a knowledge of things only through the sensations to which they give rise?
We cannot, surely, do that.

Shall we affirm that we know the external world directly, and at the same time that we do not know it directly, but only indirectly, and through the images which arise in our minds?
That seems inconsistent.

Certainly there is material for reflection here.
Nevertheless the more we reflect on that material, the more evident does it become that the plain man cannot be wrong in believing in the external world which seems revealed in his experiences.

We find that all attempts to discredit it rest upon the implicit assumption of its existence, and fall to the ground when that existence is honestly denied.

So our problem changes its form.