Their minds were geared to the old problems and to their own problems and their own politics. - C. J. Cherryh

“I frankly doubt that.”
“Ah. That is your privilege. But doubt doesn’t alter fact, sir.”

Science fiction is a dialogue, a tennis match, in which the Idea is volleyed from one side of the net to the other. Ridiculous to say that someone 'stole' an idea: no, no, a thousand times no. The point is the volley, and how it's carried, and what statement is made by the answering 'statement.' In other words — if Burroughs initiates a time-gate and says it works randomly, and then Norton has time gates confounded with the Perilous Seat, the Siege Perilous of the Round Table, and locates it in a bar on a rainy night — do you see both the humor and the volley in the tennis match?

"Honor to the earth," the abbot said, "honor to the dead in the passing of the year; honor to the living, in the coming of the new. A Great Year passes tonight. A new one begins. Let the good that is old continue and let the rest perish...."