“To me the entire uselessness of such rules^as practical guides lies in the inherent vagueness of the word "reasonable," the absolute impossibility of finding a definite standard, to be expressed in language, for the fairness and the reason of mankind, even of Judges. The reason and fairness of one man is manifestly no rule for the reason and fairness of another, and it is an awkward, but as far as I see, an inevitable consequence of the rule, that in every case where the decision of a Judge is overruled, who does or does not stop a case on the ground that there is, or is not, reasonable evidence for reasonable |men, those who overrule him say, by implication, that in the case before them, the Judge who is overruled is out of the pale of reasonable men.”

Out of Habit
Song lyrics
Variant: Art is why I get up in the morning; my definition ends there.
You know it doesn't seem fair,
That I'm living for something I can't even define.
And there you are right there, in the mean time.

Planning for Freedom (1952), p. 44

Source: The Misanthrope

Source: Blood of the Fold

Idea for a Universal History from a Cosmopolitan Point of View (1784)
Context: Reason in a creature is a faculty of widening the rules and purposes of the use of all its powers far beyond natural instinct; it acknowledges no limits to its projects. Reason itself does not work instinctively, but requires trial, practice, and instruction in order gradually to progress from one level of insight to another. Therefore a single man would have to live excessively long in order to learn to make full use of all his natural capacities. Since Nature has set only a short period for his life, she needs a perhaps unreckonable series of generations, each of which passes its own enlightenment to its successor in order finally to bring the seeds of enlightenment to that degree of development in our race which is completely suitable to Nature’s purpose. This point of time must be, at least as an ideal, the goal of man’s efforts, for otherwise his natural capacities would have to be counted as for the most part vain and aimless. This would destroy all practical principles, and Nature, whose wisdom must serve as the fundamental principle in judging all her other offspring, would thereby make man alone a contemptible plaything.

Second Thesis
Paraphrased variant: Reason does not work instinctively, but requires trial, practice, and instruction in order to gradually progress from one level of insight to another.

Epigram; reported in Bartlett's Familiar Quotations, 10th ed. (1919).

Concurring, Rita v. United States, 551 U.S. 338 (2007).

Address to the Commonwealth Parliamentary Association conference in Nadi, 8 September 2005