The following quotes are taken from:

Giorgio Agamben, What is an Apparatus? And Other Essays. Trans. David Kishik and Stefan Pedatella. Stanford University Press 2009.

Aristotle: “He who sees senses [aisthanetai] that he is seeing, he who hears senses that he is hearing, he who walks senses that he is walking, and thus for all the other activities there is something that senses that we are exerting them [hoti energoumen], in such a way that if we sense, we sense that we are sensing, and if we think, we sense that we are thinking. This is the same thing as sensing existence: existing [to einai] means in fact sensing and thinking.

            Sensing that we are alive is in and of itself sweet, for life is by nature good, and it is sweet to sense that such a good belongs to us.

            Living is desirable, above all for those who are good, since for them existing is a good and sweet thing.

            For good men, ‘con-senting’ [synaisthanomenoi, sensing together] feels sweet because they recognize the good itself, and what a good man feels with respect to himself he also feels with respect to his friend: the friend is, in fact, an other self [heteros autos]. And as all people find the fact of their own existence [to auton einai] desirable, the existence of their friends is equally—or almost equally—desirable. Existence is desirable because one senses that it is a good thing, and this sensation [aesthesis] is in itself sweet. One must therefore also ‘con-sent’ that his friend exists, and this happens by living together and by sharing acts and thoughts in common [koinonein]. In this sense, we say that humans live together [syzen], unlike cattle that share the pasture together…

            Friendship is, in fact, a community; and as we are with respect to ourselves, so we are, as well, with respect to our friends. And as the sensation of existing [aesthesis hoti estin] is desirable for us, so would it also be for our friends.” 32-33

“The friend is not an other I, but an otherness immanent to selfness, a becoming other of the self… Friendship is this desubjectification at the very heart of the most intimate sensation of the self.” 34-35

“Friends do not share something (birth, law, place, taste): they are shared by the experience of friendship.” 36