Man depends on sight primarily. Second is hearing. Here are some paraphrased ideas from Roger Fry:
With admirable economy we learn to see only as much as needed for our purposes, which is very little. Just enough to recognize and identify an object or person. They are an entry made in our mental catalogue and are no more really seen. It is only when an object exists in our lives for no other reason or purpose than to be seen that we really look at it.
Photography does not demand a response in action or create a physical change in the body but replaces chaos with order for the psyche.
Emotion presented in a picture may not be as effective as reality but projects itself more distinctly with clarity into the consciousness.
The viewer can have a detached point of view, a disinterested intensity of contemplation not available in reality.
A picture is more real than reality because of conditions in humans that prevent us from seeing plainly and precisely when we are in a state of mental unrest. The eye can see the picture with a selective and calm perspective, more information is gathered.
Seeing is visual shorthand where a picture allows all the details.
The skill of the artist is a superior perception and more sensitive reaction to his environment.
For the photographer, he shoots from artistic instinct. An innate urge to self express because he believes the way he sees is unique and important.