Lots of people attribute "Vision without execution is hallucination" to Thomas Edison. But you won't find it on Wikiquote, and none of these people provide details on where or when he allegedly said it.
I don't think he did. I think people used the words "vision" and "execution" differently back then, compared to the way we do today, especially the word "vision," which in those days would have been (in my opinion) reserved for religious contexts. The idea that execution has anything to do with vision, in those days, just didn't exist. If you told somebody back then that you were going to execute on a vision, they'd wonder what the hell you were talking about. Visions were religious phenomena and executions happened during revolutions or the administration of the death sentence. And I'm absolutely positive that the word "hallucination" became a businessman's expression of contempt during the 1960s. Before then, it was too exotic; I believe texts from Edison's day use "phantasm" heavily, and would have gone to "phantom" before they got anywhere near "hallucination."
It sticks out like a sore thumb to me. It's like if somebody told me that "Cowabunga, dude!" was a quote from George Washington. I can't even figure out why anybody believes it for a second.