“Now the maximum of perfection is called ideal, by Plato, Idea — for instance, his Idea of a Republic — and is the principle of all that is contained under the general notion of any perfection, inasmuch as the lesser grades are not thought determinable but by limiting the maximum. But God, the Ideal of perfection, and hence the principle of cognition, is also, as existing really, the principle of the creation of all perfection.”

Small Houses: Their Economic Design and Construction (1922)

Source: Night World, No. 1

Computerized Deconstruction. Appeared in Adv. Appl. Math. v. 31 (2003), 532-543.
Context: Math is perfect (in principle), but mathematicians are not (because they are humans), hence the mathematics that (human) mathematicians do is influenced by the weltanschauung of the people around them.

Source: Jonathan Livingston Seagull

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)

Pearls of Wisdom

Source: Lectures on Philosophy (1959), p. 87

Source: Personal Destinies: A Philosophy of Ethical Individualism (1976), p. 80

Source: Anarcho-Syndicalism (1938), Ch. 1 "Anarchism: Its Aims and Purposes"
Context: Anarchism is no patent solution for all human problems, no Utopia of a perfect social order, as it has so often been called, since on principle it rejects all absolute schemes and concepts. It does not believe in any absolute truth, or in definite final goals for human development, but in an unlimited perfectibility of social arrangements and human living conditions, which are always straining after higher forms of expression, and to which for this reason one can assign no definite terminus nor set any fixed goal. The worst crime of any type of state is just that it always tries to force the rich diversity of social life into definite forms and adjust it to one particular form, which allows for no wider outlook and regards the previously exciting status as finished. The stronger its supporters feel themselves, the more completely they succeed in bringing every field of social life into their service, the more crippling is their influence on the operation of all creative cultural forces, the more unwholesomely does it affect the intellectual and social development of any particular epoch.