“Reason is to the philosopher what grace is to the Christian.
Grace causes the Christian to act, reason the philosopher.”
Article on Philosophy, Vol. 25, p. 667, as quoted in Main Currents of Western Thought : Readings in Western European Intellectual History from the Middle Ages to the Present (1978) by Franklin Le Van Baumer
Variant translation: Reason is to the philosopher what grace is to the Christian. Grace moves the Christian to act, reason moves the philosopher. Other men walk in darkness; the philosopher, who has the same passions, acts only after reflection; he walks through the night, but it is preceded by a torch. The philosopher forms his principles on an infinity of particular observations. … He does not confuse truth with plausibility; he takes for truth what is true, for forgery what is false, for doubtful what is doubtful, and probable what is probable. … The philosophical spirit is thus a spirit of observation and accuracy.
L'Encyclopédie (1751-1766)
Context: Reason is to the philosopher what grace is to the Christian.
Grace causes the Christian to act, reason the philosopher. Other men are carried away by their passions, their actions not being preceded by reflection: these are the men who walk in darkness. On the other hand, the philosopher, even in his passions, acts only after reflection; he walks in the dark, but by a torch.
The philosopher forms his principles from an infinity of particular observations. Most people adopt principles without thinking of the observations that have produced them, they believe the maxims exist, so to speak, by themselves. But the philosopher takes maxims from their source; he examines their origin; he knows their proper value, and he makes use of them only in so far as they suit him.
Truth is not for the philosopher a mistress who corrupts his imagination and whom he believes to be found everywhere; he contents himself with being able to unravel it where he can perceive it. He does not confound it with probability; he takes for true what is true, for false what is false, for doubtful what is doubtful, and probable what is only probable. He does more, and here you have a great perfection of the philosopher: when he has no reason by which to judge, he knows how to live in suspension of judgment...
The philosophical spirit is, then, a spirit of observation and exactness, which relates everything to true principles...
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Denis Diderot 106
French Enlightenment philosopher and encyclopædist 1713–1784Related quotes

“The command to a Christian couple is: "Grow in grace and love together."”
Contraception and Chastity (1975)
Context: If a kind of love cannot be commanded, we can't build our moral theology of marriage on the presumption that it will be present. Its absence is sad, but this sadness exists, it is very common. We should avoid, I think, using the indicative mood for what is really a commandment like the Scout Law ("A Boy Scout is kind to animals" - it means a Boy Scout ought to be kind to animals). For if we hear: "a Christian couple grow in grace and love together" doesn't the question arise "supposing they don't?" It clears the air to substitute the bite of what is clearly a precept for the sweetness of a rosy picture. The command to a Christian couple is: "Grow in grace and love together." But a joint command can only be jointly obeyed. Suppose it isn't? Well, there remains the separate precept to each and in an irremediably unhappy marriage, one ought still to love the other, though not perhaps feeling the affection that cannot be commanded. Thus the notion of the "marriage debt" is a very necessary one, and it alone is realistic: because it makes no assumption as to the state of the affections.
Looking at the rightness of the marriage act like this will help in another way. It will prevent us from assuming that the pleasant affection which exists between a happy and congenial pair is the fulfilment of the precept of love. (It may after all only be a complacent hiving off together in a narrow love.) We ought absolutely not to give out a teaching which is flattering to the lucky, and irrelevant to the unhappy. Looked at carefully, too, such teaching is altogether too rigorist in a new direction. People who are not quite happily married, not lucky in their married life, but nevertheless have a loyalty to the bond, are not, therefore, bound to abstain from intercourse.

Rom 12:1; Eph 4:23; Gal 2:20
Page 27.
Golden Booklet of the True Christian Life (1551)

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 365.

“Patience and perseverance are never more thoroughly Christian graces than when features of prayer.”
Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 461.

“The history of philosophical system is the picture gallery of reason.”
Z. Hanfi, trans., in The Fiery Brook (1972), p. 68
Towards a Critique of Hegel’s Philosophy (1839)

“What is now decisive against Christianity is our taste, no longer our reasons.”
Sec. 132
The Gay Science (1882)

Political, Moral, and Miscellaneous Reflections (1750), Moral Thoughts and Reflections