"To cut off pleasures from the consequences and conditions which they have by nature, detaching, as it were, the precious phrase from its irrelevant context, is what distinguishes the man from the brute and the citizen from the savage."

     "'It wasn't scenery we were looking for,' said John.  'I am trying to find the Island in the West.'
     "'You refer, no doubt, to some æsthetic experience.  There again—I would not urge a young man to shut his eyes to that sort of thing.  Who has not felt immortal longings at the lengthening of the shadow or the turning of the leaf?  Who has not stretched out his hands for the ulterior shore?  Et ego in Arcadia!  We have all been fools once—aye, and are glad to have been fools too.  But our imaginations, like our appetites, need discipline; not, heaven help us, in the interest of any transcendental ethic, but in the interests of our own solid good.  That wild impulse must be tasted, not obeyed.  The bees have stings, but we rob them of their honey.  To hold all that urgent sweetness to our lips in the cup of one perfect moment, missing no faintest ingredient in the flavour of its μονόχρονος ἡδονή, yet ourselves, in a sense, unmoved—this is the true art.  This tames in the service of the reasonable life even those pleasures whose loss might seem to be the heaviest, yet necessary, price we paid for rationality.  Is it an audacity to hint that for the corrected palate the taste of the draught even owes its last sweetness to the knowledge that we have wrested it from an unwilling source?  To cut off pleasures from the consequences and conditions which they have by nature, detaching, as it were, the precious phrase from its irrelevant context, is what distinguishes the man from the brute and the citizen from the savage.  I cannot join with those moralists who inveigh against the Roman emetics in their banquets:  still less with those who would forbid the even more beneficent contraceptive devices of our later times.  That man who can eat as taste, not nature, prompts him and yet fear no aching belly, or who can indulge in Venus and fear no impertinent bastard, is a civilized man.  In him I recognize Urbanity—the note of the centre."

     Mr. Sensible, in C. S. Lewis, The pilgrim's regress:  an allegorical apology for Christianity, reason, and romanticism V.4 ((Grand Rapids, MI:  Wm. B. Eerdmans Publishing Company, 1974/1958 [1943/1933]), 84-85).
     Et ego in Arcadia!  "‘And I too in Arcadia’; a tomb inscription, of disputed interpretation, often depicted in classical paintings, notably by Poussin in 1655" (Oxford dictionary of phrase and fable, 2nd ed., ed. Elizabeth Knowles, (2005)); "The Latin tag familiar from seventeenth-century pastoral paintings, et in Arcadia ego, often translated as ‘I too [have lived] in Arcadia’, may more correctly mean ‘I [am found] even in Arcadia’, and refer to death" (Oxford companion to classical literature, 3rd ed., ed. M. C. Howatson (2011)); "the grim intrusion of death into the pastoral world" (Oxford companion to Hardy, ed. Norman Page (2001), s.v. pastoralism, by R. P. Draper); "And I too in Arcadia.  tomb inscription, of disputed meaning, often depicted in classical paintings, notably by Poussin in 1655; E. Panofsky ‘Et in Arcadia ego’ in R. K. Klibansky and H. J. Paton (eds.) Philosophy and History: Essays Presented to E. Cassirer (1936)" (Oxford essential quotations, ed. Susan Ratcliffe (2012)); etc.
     μονόχρονος ἡδονή  momentary pleasure.  Cf. the μονόχρονος εὐδαιμονία of Aristippus ap. Ath[enaeus Grammaticus] 12.544a (LSJ).  Yet, contra LSJ, there is only one occurrence of μονόχρονος in the whole of Aristippi et Cyrenaicorum fragmenta, ed. Erich Mannebach (Brill, 1961), no. 207 (on p. 48), where "Athen. XII p. 544 a-b" is again the citation and what appears is "μονόχρονον αὐτὴν (sc. τὴν ἡδυπάθειαν[, pleasant living or luxury])", with a reference back to no. 157, where "Athen. XII p. 544 a" (but not μονόχρονος) again appears.  Cf. Loeb classical library 327 =Athenaeus VI, ed. & trans. S. Douglas Olson (Cambridge:  Harvard University Press, 2010), pp. 164-165 (=Athenaei Navcratitae Dipnosophistarvm libri XV, ed. Kaibel, vol. 3 (Leipzig:  Teubner, 1890), p. 199):

     Entire philosophical sects laid claim to the idea of organizing one's life around luxury, for example the so-called Cyrenaic sect, which originated with Socrates' student Aristippus (frr. 157, 207 Mannebach = SSR IV A 174), who expressed his approval of a life of luxury, and said that this is what one should aim for, as well as what happiness is based on.  He also argued that pleasure exists only in the individual moment [(ὃς ἀποδεξάμενος τὴν ἡδυπάθειαν ταύτην τέλος εἶναι ἔφη καὶ ἐν αὐτῇ τὴν εὐδαιμονίαν βεβλῆσθαι·  καὶ μονόχρονον αὐτὴν εἶναι, who, approving of pleasure [(τὴν ἡδυπάθειαν)], was saying that this [(ταύτην = τὴν ἡδυπάθειαν)] is the aim and that happiness [(τὴν εὐδαιμονίαν)] has been founded on it, and that it [(αὐτὴν = either τὴν εὐδαιμονίαν or τὴν ἡδυπάθειαν)] is momentary)]. . . .

The point being that either either τὴν εὐδαιμονίαν or τὴν ἡδυπάθειαν could be the referent of the αὐτὴν associated with μονόχρονον (to the vindication of LSJ).
     Cf. the reference to hedupatheia here:  "Aristippus welcomed the experience of pleasure (hedupatheia), and said it is the end, and that happiness is founded on it. And he said that it was for a single time only (monochronos). Like prodigal people, he thought that neither the memory of past gratifications nor the expectation of future ones was anything to him, but he discerned the good by the single present time alone. He regarded having been gratified and being about to be gratified as nothing to him, on the ground that the one no longer is and the other is not yet and is unclear--just like what happens to self-indulgent people, who suppose that only what is present benefits them. (Athenaeus, Deipn. xiv 514a)" (T.H. Irwin, "Aristippus against happiness," Monist 74, no. 1 (January 1991):  55-82).