The Hancock-Henderson Quill, Inc.
"A man cannot prove a negative, but he has a right to claim that when a man makes an affirmative charge, he must offer some proof to show the truth of what he says.
I certainly cannot introduce testimony to show the negative about things, but I have a right to claim that if a man says he knows a thing, then he must show how he knows it.
I always have a right to claim this, and it is not satisfactory to me that he may be "conscientious" on the subject."
First debate with Stephen Douglas, 1858