Why did Emerson deny his original views and theories?

The strange thing is that just when the "revolution" was about to succeed, Emerson suddenly backed down. In 1891, he completely rejected his original views and theories in a pamphlet called "The Destruction of Naturalistic Photography". He wrote:

I once believed that true light and shade, as in nature, could be obtained and could be altered at will by development. However, this is actually impossible to do.

Emerson’s dramatic change caught everyone by surprise. The reason for this change is that he learned that photography has a fixed tonal range, and the photographer's control is limited.