Giorgio Vasari, in his "Lives of the Artists" (1550) wrote that Leonardo’s “cast of mind was so heretical that he did not adhere to any religion,”
Art historian Sir Kenneth Clark describes Leonardo as “not a religious-minded man." “In his notebooks and letters, Leonardo protested the sale of indulgences, liturgical and ceremonial pomp, obligatory confessions, and the cult of the saints. He assailed the clergy—at all levels—for their lack of morality, values, and education. As a scientist, he questioned the contemporary reality of miracles performed by priests and monks.”
Johannes Kepler “regarded the Copernican theory as literally true -- not a convenient fiction. With respect to questionable Biblical passages (e.g. Josh. 10: 12, Ps. 104, Job 34), he noted, "It is not the purpose of the Holy Scriptures to instruct men in natural things." Despite his exemplary life, he was denied communion by his own Lutheran church, first at Graz, finally by Tübingen in answer to his formal petition. Although he subscribed wholeheartedly to the Augsburg Confession (15 30), he could not quite endorse the Book of Concord (1580) because of its doctrine of the omnipresence of Christ (e.g., in the sacrament). He preferred the Calvinistic emphasis upon remembrance, but could not accept its complementary insistence upon predestination. He regarded himself as a catholic (including Lutherans and Calvinists, as well as Roman Catholics), but he could not agree with the Papacy (e.g., it's idolatry, saints, et al.)."
Sir Isaac Newton was an antitrinitarian, an Arian (someone who rejects the divinity and resurrection of Christ) and an anti-papist. Not to mention an Alchemist - a grotesque lapse of one of the most, if not the most powerful minds of all time.
"In his own era, Descartes was accused of harboring secret deist or atheist beliefs. Contemporary Blaise Pascal said that "I cannot forgive Descartes; in all his philosophy, Descartes did his best to dispense with God. But Descartes could not avoid prodding God to set the world in motion with a snap of his lordly fingers; after that, he had no more use for God."
If we go beyond the facile generalizations and glossing over of facts, which informs the intellectual dishonesty of religion apologists, we find "extremely devout people" not so devout after all and/or rather conflicted indeed by the cognitive dissonance inevitably caused by the insurmountable contradiction between ethics and religion, and the insurmountable contradiction between science and religion.
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