Gottfried Leibniz: Reason

“Now, as there is an infinity of possible universes in the Ideas of God, and as only one of them can exist, there must be a sufficient reason for God's choice, which determines him toward one rather than another. And this reason can be found only in the fitness, or the degrees of perfection, that these worlds contain, since each possible thing has the right to claim existence in proportion to the perfection it involves.”

Gottfried Leibniz

Or, comme il y a une infinité d'univers possibles dans les idées de Dieu, et qu'il n'en peut exister qu'un seul, il faut qu'il y ait une raison suffisante du choix de Dieu qui le détermine à l'un plutôt qu'à l'autre. Et cette raison ne peut se trouver que dans la convenance, dans les degrés de perfection que ces mondes contiennent, chaque possible ayant droit de prétendre à l'existence à mesure de la perfection qu'il enveloppe.
La monadologie (53 & 54).
The Monadology (1714)

God , World , Idea , Universe

“Although the whole of this life were said to be nothing but a dream and the physical world nothing but a phantasm, I should call this dream or phantasm real enough, if, using reason well, we were never deceived by it.”

Gottfried Leibniz

As quoted in The World of Mathematics (1956) by J. R. Newman, p. 1832

Life , World , Dreams

“We never have a full demonstration, although there is always an underlying reason for the truth, even if it is only perfectly understood by God, who alone penetrated the infinite series in one stroke of the mind.”

Gottfried Leibniz

The Shorter Leibniz Texts (2006) http://books.google.com/books?id=oFoCY3xJ8nkC&dq edited by Lloyd H. Strickland, p. 111

God , Truth

“There are two famous labyrinths where our reason very often goes astray. One concerns the great question of the free and the necessary, above all in the production and the origin of Evil. The other consists in the discussion of continuity, and of the indivisibles which appear to be the elements thereof, and where the consideration of the infinite must enter in.”

Gottfried Leibniz book Théodicée

Il y a deux labyrinthes fameux où notre raison s’égare bien souvent : l'un regarde la grande question du libre et du nécessaire, surtout dans la production et dans l'origine du mal ; l'autre consiste dans la discussion de la continuité et des indivisibles qui en paraissent les éléments, et où doit entrer la considération de l'infini.
Théodicée (1710)ː Préface

Question , Appearance , Evil

“There are two kinds of truths: those of reasoning and those of fact. The truths of reasoning are necessary and their opposite is impossible; the truths of fact are contingent and their opposites are possible.”

Gottfried Leibniz

Il y a aussi deux sortes de vérités, celles de Raisonnement et celle de Fait. Les vérités de Raisonnement sont nécessaires et leur opposé est impossible, et celles de Fait sont contingentes et leur opposé est possible.
La monadologie (33).
The Monadology (1714)

Truth

“The love of God consists in an ardent desire to procure the general welfare, and reason teaches me that there is nothing which contributes more to the general welfare of mankind than the perfection of reason.”

Gottfried Leibniz

Closing sentence of the Preface to the general science (1677) (in P. Wiener (ed.), Leibniz Selections, Macmilland Press Ltd, 1951).

Perfection , Love , Making love , God