Sir William Blackstone, the great English jurist, writing in his Commentaries on the Laws of England in 1769, was most explicit in emphasizing the weakness of man's nature. As he observed: ". . . if our reason were always, as in our first ancestor before his transgression, clear and perfect,unruffled by passions, unclouded by prejudice, unimpaired by disease or intemperance, the task would be pleasant and easy; we should need no other guide but this. But every man now finds the contrary in his own experience; that his reason is corrupt, and his understanding full of ignorance and error. This has given manifold occasion for the benign interposition of divine Providence, which in compassion to the frailty, the imperfection, and the blindness of human reason, hath been pleased at sundry times and in divers manners, to discover and enforce its laws by an immediate and direct revelation. The doctrines thus delivered we call the revealed or divine law . . ."
Source: Three Minutes by James Keller, M. M., 1950
Geometry enlightens the intellect and sets one's mind right. All of its proofs are very clear and orderly. It is hardly possible for errors to enter into geometrical reasoning, because it is well arranged and orderly. Thus, the mind that constantly applies itself to geometry is not likely to fall into error. In this convenient way, the person who knows geometry acquires intelligence.
Ibn Khaldun (1332 - 1406)
Source: The Muqaddimah. An Introduction to History.
The world always makes the assumption that the exposure of an error is identical with the discovery of the truth - that error and truth are simply opposite. They are nothing of the sort. What the world turns to, when it has been cured of one error, is usually simply another error, and maybe one worse than the first.
Anyone who studies the state of things which preceded the French Revolution will see that the tremendous catastrophe came about from so excessive a regulation of men's actions in all their details, and such an enormous drafting away of the products of their actions to maintain the regulating organization, that life was fast becoming impracticable. And if we ask what then made, and now makes, this error possible, we find it to be the political superstition that governmental power is subject to no restraints.