— Francis Bacon English philosopher, statesman, scientist, jurist, and author 1561 - 1626
— Albert Einstein German-born physicist and founder of the theory of relativity 1879 - 1955
— Thomas Aquinas Italian Dominican scholastic philosopher of the Roman Catholic Church 1225 - 1274
— Pythagoras ancient Greek mathematician and philosopher -585 - -500 a.C.
— Catiline ancient Roman Senator -108 - -62 a.C.
As quoted by Sallust (86 BC – c. 35 BC) in Catiline's War, Book XX, pt. 4 (trans. J. C. Rolfe). Variant translations: To like and dislike the same things, that is indeed true friendship. To like the same things and to dislike the same things, only this is a strong friendship.
„[The integrative system] deals with such matters as respect, legitimacy, community, friendship, affection, love, and of course their opposites, across a broad scale of human relationships and interactions.“
— Kenneth E. Boulding British-American economist 1910 - 1993
p. 670-671 as cited in: Christopher Spicer (1997) Organizational Public Relations: A Political Perspective. p. 248 Spicer (1997) explains: "Boulding (1989) referred to three independent systems from which power is exercised in our society: threat, production and exchange, and integrative. The threat system is one in which power is accomplished through coercion in its many guises, often including asymmetrical one-way persuasive communication exchanges. The production and exchange system speaks to the economic system, of which public relations is certainly a part. And, finally, the integrative system.
„The process of falling in love at first sight is as final as it is swift in such a case, but the growth of true friendship may be a lifelong affair.“
— Sarah Orne Jewett American novelist, short story writer and poet 1849 - 1909
„We live, in fact, in a world starved for solitude, silence, and privacy: and therefore starved for meditation and true friendship.“
— Clive Staples Lewis Christian apologist, novelist, and Medievalist 1898 - 1963