“Biot, who assisted Laplace in revising it [The Mécanique Céleste] for the press, says that Laplace himself was frequently unable to recover the details in the chain of reasoning, and if satisfied that the conclusions were correct, he was content to insert the constantly recurring formula, 'Il est àisé avoir' [it is easy to see].” ReasonScienceMathFormulaLaplacePierre Simon LaplaceBiotJean Baptiste Biot Book:A Short Account of the History of Mathematics Source: A Short Account of the History of Mathematics