Russell Ackoff
Russell Ackoff

The extensive literature addressed to the definition or characterization of science is filled with inconsistent points of view and demonstrates that an adequate definition is not easy to attain. Part of the difficulty arises from the fact that the meaning of science is not fixed, but is dynamic. As science has evolved, so has its meaning. It takes on a new meaning and significance with successive

ages.

Chi­ma­man­da Ngo­zi Adi­chie
Chi­ma­man­da Ngo­zi Adi­chie

My own definition is a feminist is a man or a woman who says, yes, there’s a problem with gender as it is today and we must fix it, we must do better. All of us, women and men, must do better.

Leon Battista Alberti
Leon Battista Alberti

Der Kürze halber möchte ich die Definition geben, daß die Schönheit eine bestimmte gesetzmäßige Übereinstimmung aller Teile, was immer für eine Sache, sei, die darin besteht, daß man weder etwas hinzufügen noch hinwegnehmen könnte, ohne sie weniger gefällig zu machen.

Steve Allen
Steve Allen

God is by definition the holder of all possible knowledge, it would be impossible for him to have faith in anything. Faith, then, is built upon ignorance and hope.

Louis Althusser
Louis Althusser

Those who are in ideology believe themselves by definition outside ideology: one of the effects of ideology is the practical denegation of the ideological character of ideology by ideology: ideology never says, ‘I am ideological’. It is necessary to be outside ideology, i. e. in scientific knowledge, to be able to say: I am in ideology (a quite exceptional case) or (the general case): I was in

ideology. As is well known, the accusation of being in ideology only applies to others, never to oneself (unless one is really a Spinozist or a Marxist, which, in this matter, is to be exactly the same thing). Which amounts to saying that ideology has no outside (for itself), but at the same time that it is nothing but outside

Martin Amis
Martin Amis

A joke is by definition politically incorrect — it assumes a butt, and a certain superiority in the teller. The culture won't put up with that for much longer.

Perry Anderson
Perry Anderson

Values – ethical, epistemological, aesthetic – figure in the contests over the field, but they do not define it. Intellectuals are judged not by their morals, but by the quality of their ideas, which are rarely reducible to simple verdicts of truth or falsity, if only because banalities are by definition accurate.

Aristóteles
Aristóteles

[L]et us consider, with respect to causes, what they are, and how many there are in number… this also must be done by us in discoursing concerning generation and corruption, and all physical mutation… knowing the principles of these…
Cause… is after one manner said to be that, from which, being inherent, something is produced… But after another manner cause is form and paradigm (and

this is the definition of the essence of a thing) and the genera of this. …But it happens… that there are also many causes of the same thing, and this is not from accident. …seed, a physician, he who consults, and, in short, he who makes, are all of them causes, as that whence the principle of mutation, or permanency, or motion is derived. …It is, however, necessary always to investigate

the supreme cause of every thing …Further still, it is necessary to investigate the genera of genera; and the particulars of particulars… We should also explore the capacities of the capabilities, and the energizers of the things affected by energy.

Herbert Henry Asquith
Herbert Henry Asquith

Peace we all desire. Peace can only come—peace, I mean, that is worth the name and that satisfies the definition of the word—peace will only come on terms that atonement is made for past wrongs, that the weak and downtrodden are restored, that the faith of treaties is observed, and that the sovereignty of public law is securely enthroned over the nations of the world.

Joaquim Maria Machado de Assis
Joaquim Maria Machado de Assis

The best definition of love in the world is not worth one kiss from the girl you love.