The practice of Pictorial Photography cannot be taught by a Kindergarten system; the mere comparison with typical examples must be accompanied with a… - Alfred Horsley Hinton

It must be remembered that after all in making a picture we are endeavoring to set down on one plane various objects in such a way as to suggest an infinitude of varying planes, and hence we are justified in selecting such conditions of nature as shall help us to give the impression of truthfulness, even though it be not in particular cases absolutely true to fact.

Justification must be sought in the fact that "no very great incongruity is observable."

With most of us, even without special training, there is a certain instinctive sense of proportion, and thus we recognize the relative distance of objects by their relative size.