"Rules for Definitions. I. Not to undertake to define any of the things so well known of themselves that the clearer terms cannot be had to explain them. II. Not to leave any terms that are at all obscure or ambiguous without definition. III. Not to employ in the definition of terms any words but such as are perfectly known or already explained."

“If it had pleased them [the legislators] to order that this wealth, after having been possessed by fathers during their life, should return to the republic after their death, you would have no reason to complain of it.”

“When I consider the short duration of my life, swallowed up in the eternity before and after, the small space which I fill, or even can see, engulfed in the infinite immensity of spaces whereof I know nothing, and which know nothing of me, I am terrified, and wonder that I am here rather than there, for there is no reason why here rather than there, or now rather than then. Who has set me here? By whose order and design have this place and time been destined for me?—Memoria hospitis unius diei prætereuntis.It is not well to be too much at liberty. It is not well to have all we want.How many kingdoms know nothing of us!The eternal silence of these infinite spaces alarms me.”

“FEU. Dieu d'Abraham, Dieu d'Isaac, Dieu de Jacob, non des philosophes et savants. Certitude. Certitude. Sentiment. Joie. Paix.”

“Je n'ai fait celle-ci plus longue que parce que je n'ai pas eu le loisir de la faire plus courte.”

“Nature, which alone is good, is wholly familiar and common.”

“This art, which I call the art of persuading, and which, properly speaking, is simply the process of perfect methodical proofs, consists of three essential parts: of defining the terms of which we should avail ourselves by clear definitions, of proposing principles of evident axioms to prove the thing in question; and of always mentally substituting in the demonstrations the definition in the place of the thing defined.”