Objection 1: It would seem that memory and hope do not cause pleasure. Because pleasure is caused by present good, as Damascene says (De Fide Orth. ii, 12). But hope and memory regard what is absent: since memory is of the past, and hope of the future. Therefore memory and hope do not cause pleasure.
Obj. 2: Further, the same thing is not the cause of contraries. But hope causes affliction, according to Prov. 13:12: "Hope that is deferred afflicteth the soul." Therefore hope does not cause pleasure.
Obj. 3: Further, just as hope agrees with pleasure in regarding good, so also do desire and love. Therefore hope should not be assigned as a cause of pleasure, any more than desire or love.
On the contrary, It is written (Rom. 12:12): "Rejoicing in hope"; and (Ps. 76:4): "I remembered God, and was delighted."
I answer that, Pleasure is caused by the presence of suitable good, in so far as it is felt, or perceived in any way. Now a thing is present to us in two ways. First, in knowledge--i.e. according as the thing known is in the knower by its likeness; secondly, in reality--i.e. according as one thing is in real conjunction of any kind with another, either actually or potentially. And since real conjunction is greater than conjunction by likeness, which is the conjunction of knowledge; and again, since actual is greater than potential conjunction: therefore the greatest pleasure is that which arises from sensation which requires the presence of the sensible object. The second place belongs to the pleasure of hope, wherein there is pleasurable conjunction, not only in respect of apprehension, but also in respect of the faculty or power of obtaining the pleasurable object. The third place belongs to the pleasure of memory, which has only the conjunction of apprehension.
Reply Obj. 1: Hope and memory are indeed of things which, absolutely speaking, are absent: and yet those are, after a fashion, present, i.e. either according to apprehension only; or according to apprehension and possibility, at least supposed, of attainment.
Reply Obj. 2: Nothing prevents the same thing, in different ways, being the cause of contraries. And so hope, inasmuch as it implies a present appraising of a future good, causes pleasure; whereas, inasmuch as it implies absence of that good, it causes affliction.
Reply Obj. 3: Love and concupiscence also cause pleasure. For everything that is loved becomes pleasing to the lover, since love is a kind of union or connaturalness of lover and beloved. In like manner every object of desire is pleasing to the one that desires, since desire is chiefly a craving for pleasure. However hope, as implying a certainty of the real presence of the pleasing good, that is not implied either by love or by concupiscence, is reckoned in preference to them as causing pleasure; and also in preference to memory, which is of that which has already passed away.