The letter was the only evidence in black and white.
"I do believe I've got the only evidence there is."
The book is not the only evidence of new attitudes.
And as Cardinal said, growth is the only evidence of life.
The only evidence against him is a confession he has never read.
The only hard evidence we have is our own experience on Earth.
The only evidence are the memories of people who had lived then.
And up into the sky went the only physical evidence of the Project.
His only evidence that the woman actually existed was gone.
The only evidence to her origins come from what she can do, which seems to be almost anything.