“The full famous quote, in context

Although Einstein would go on to write many more influential papers, the discovery of General Relativity would always loom as his most colossal scientific achievement. In 1929, while being interviewed for the Saturday Evening Post by George Sylvester Viereck, the following exchange occurred:

Einstein: “I believe in intuitions and inspirations. I sometimes feel that I am right. I do not know that I am. When two expeditions of scientists, financed by the Royal Academy, went forth to test my theory of relativity, I was convinced that their conclusions would tally with my hypothesis. I was not surprised when the eclipse of May 29, 1919, confirmed my intuitions. I would have been surprised if I had been wrong.”

Viereck: “Then you trust more to your imagination than to your knowledge?”

Einstein: “I am enough of the artist to draw freely upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.

In other words, the first time this quote appeared, it was in the context of Einstein believing that he knew how an experimental/observational result would turn out before it was conducted, on the basis of the previously-established success of his theory. It wasn’t a foregone conclusion, but he chalked up his physical intuition about a yet-to-be-determined measurement to “imagination,” rather than “knowledge,” in response to a leading question from a reporter.”