True.

But have you remarked that sight is by far the most costly and complex piece of workmanship which the artificer of the senses ever contrived?

No, I never have, he said.

Then reflect; has the ear or voice need of any third or additional nature in order that the one may be able to hear and the other to be heard?

Nothing of the sort.

No, indeed, I replied; and the same is true of most, if not all, the other senses — you would not say that any of them requires such an addition?

Certainly not.

But you see that without the addition of some other nature there is no seeing or being seen?