“Learning isn’t a means to an end; it is an end in itself.”

As quoted in World Marxist Review : Problems of Peace and Socialism (1958), p. 40
Context: Democracy and socialism are means to an end, not the end itself. We talk of the good of society. Is this something apart from, and transcending, the good of the individuals composing it? If the individual is ignored and sacrificed for what is considered the good of the society, is that the right objective to have?
It was agreed that the individual should not be sacrificed and indeed that real social progress will come only when opportunity is given to the individual to develop, provided "the individual" is not a selected group but comprises the whole community. The touchstone, therefore, should be how far any political or social theory enables the individual to rise above his petty self and thus think in terms of the good of all. The law of life should not be competition or acquisitiveness but cooperation, the good of each contributing to the good of all.

The History of Freedom in Antiquity (1877)
Context: Liberty and good government do not exclude each other; and there are excellent reasons why they should go together. Liberty is not a means to a higher political end. It is itself the highest political end. It is not for the sake of a good public administration that it is required, but for security in the pursuit of the highest objects of civil society, and of private life.

Directives on the Cultural Revolution (1966-1972)

Quote in 'Artist's Voice', Kuh; as cited in Outside the Lines, David W. Galenson, Harvard University Press, 2001, p. 109
posthumous

Variant: It had to teach her to think of love as a state of grace: not the means to anything but the alpha and omega, an end it itself.
Source: Love in the Time of Cholera

The scope and nature of the constitutional guarantee of the freedom of the press are to be viewed and applied in that light.
New York Times (November 28, 1954).
Judicial opinions

Attributed

"Do Liberals Have an Answer to Trump on Foreign Policy?" (March 2017)