Man is certainly mad. He cannot fashion a worm, and he fashions gods by dozens.

[L’homme est bien insensé: Il ne sçauroit forger un ciron, & forge des Dieux à douzaines.]

Michel de Montaigne (1533-1592) French essayist

Essays, Book 2, ch. 12 (2.12), “Apology for Raymond Sebond [Apologie de Raimond de Sebonde]” (1573) [tr. Zeitlin (1934)]
    (Source)

This essay appeared in the 1st (1580) edition, and was expanded for each edition after that. This passage first appeared in the 3rd (1595) edition.

(Source (French)). Alternate translations:

Oh sencelesse man, who can not possibly make a worme, and yet will make Gods by dozens.
[tr. Florio (1603)]

Man is certainly stark mad; he cannot make a flea, and yet gods by dozens.
[tr. Cotton (1686)]

Man is certainly stark mad; he cannot make a worm, and yet he will be making gods by dozens.
[tr. Cotton/Hazlitt (1877)]

Man is indeed mad. He could not fashion a worm, and he fashions gods by the dozen.
[tr. Ives (1925)]

Man is certainly crazy. He could not make a mite, and he makes gods by the dozens.
[tr. Frame (1943)]

Man is quite insane. He wouldn't know how to create a maggot, and he creates gods by the dozen.
[ed. Rat (1958)]

Man is indeed out of his mind. He cannot even create a fleshworm, yet creates gods by the dozen.
[tr. Screech (1987)]