“As character comprises the entire sphere of the educated will, so temperament is nothing else than the sum of our natural inclinations and tendencies. Inclination is the material of the will, developing itself when controlled, into character, and when controlling, into passions. Temperament is, therefore, the root of our passions; and the latter, like the former, may be distinguished into two principal classes. Intelligent psychologists and physicians have always recognised this fact…”

1770s, Boston Massacre trial (1770)
Variant: Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence.
Source: The Portable John Adams

“Confusing ‘Character’ with ‘Temperament’”
Clearing the Ground (1986)
Context: Character is something you forge for yourself; temperament is something you are born with and can only slightly modify. Some people have easy temperaments and weak characters; others have difficult temperaments and strong characters.
We are all prone to confuse the two in assessing people we associate with. Those with easy temperaments and weak characters are more likable than admirable; those with difficult temperaments and strong characters are more admirable than likable. Of course, the optimum for a person is to possess both an easy temperament and a strong character, but this is a rare combination, and few of us are that lucky. The people who get things done tend to be prickly, and the people we enjoy being with tend to be accepting, and there seems to be no way to get around this. Obviously, there are many combinations of character and temperament, in varying degrees, so that this is only a rough generalization — but I think it is one worth remembering when we make personal judgments.

Ibid., p. 413<ǃ--Assírio & Alvim, 2008-->
As quoted in Os Grandes Trechos, Richard Zenith Edition, Lisbon, 2006, p. 413
The Book of Disquiet
Original: Ter opiniões definidas e certas, instintos, paixões e carácter fixo e conhecido — tudo isto monta ao horror de tornar a nossa alma num facto, de a materializar e tornar exterior.

Summa Contra Gentiles, III,126,3

Source: Fugitive Essays: Selected Writings of Frank Chodorov (1980), p. 397, “Freedom Is Better,” Plain Talk, (November 1949)

Source: Man for Himself (1947), Ch. 3
Context: Temperament refers to the mode of reaction and is constitutional and not changeable; character is essentially formed by a person’s experiences, especially of those in early life, and changeable, to some extent, by insights and new kinds of experiences. If a person has a choleric temperament, for instance, his mode of reaction is "quick and strong.” But what he is quick or strong about depends on his kind of relatedness, his character. If he is a productive, just, loving person he will react quickly and strongly when he loves, when he is enraged by injustice, and when he is impressed by a new idea. If he is a destructive or sadistic character, he will be quick and strong in his destructiveness or in his cruelty. The confusion between temperament and character has had serious consequences for ethical theory. Preferences with regard to differences in temperament are mere matters of subjective taste. But differences in character are ethically of the most fundamental importance.

Delacroix était passionnément amoureux de la passion, et froidement déterminé à chercher les moyens d'exprimer la passion de la manière la plus visible. Dans ce double caractère, nous trouvons, disons-le en passant, les deux signes qui marquent les plus solides génies, génies extrêmes.
L’œuvre et la vie d’Eugène Delacroix http://fr.wikisource.org/wiki/L%27%C5%92uvre_et_la_vie_d%27Eug%C3%A8ne_Delacroix#III [The Life and Work of Eugène Delacroix] (1863), published in Curiosités esthétiques (1868)

Interview with Einstein (1930)
Context: Our passions and desires are unruly, but our character subdues these elements into a harmonious whole. Does something similar to this happen in the physical world? Are the elements rebellious, dynamic with individual impulse? And is there a principle in the physical world which dominates them and puts them into an orderly organization? … It is the constant harmony of chance and determination which makes it eternally new and living.