“Mirabeau and Sieyès are the two strongest minds of the Revolution,” said Talleyrand who knew both of them well. This is no doubt true. It is likewise true that Mirabeau and Sieyes were at opposite poles from each other intellectually. Sieyès was a political theorist; they called him the brain. Mirabeau, on the other hand, was the least theoretical of men. When the Estates General opened he had no draft of a Constitution; Sieyès, on the other hand, had thought of one and even several.

For the whole course of the Revolution until his death in April, 1791, Mirabeau cannot be described by an invariable formula. He cannot be classified in the pro-English school. He wrote to a minister before the Revolution: “the executive life” suited him better than “the speculative life.” Sieyès, and even Mounier, would have been wonderful professors of Constitutional Law. Not Mirabeau. His culture was enormous but disorganized. An omnivorous reader and always with pen in hand, he had made innumerable excerpts from all sorts of books, and drew upon them with no scruples about plagiarism when he wrote his own works. One must be careful to avoid the temptation, to which some have succumbed, of seeing in these plagiarisms the expression of Mirabeau's own ideas.