“Of course,” said Parry, “the hedonistic calculus is difficult to apply.  No one, that I know of, denies that.”

“No one could very well deny it,” I replied.  “But now, see what follows.  Granting, for the moment, for the sake of argument, that in making these difficult choices we really do apply what you call the hedonistic calculus—­”

“Which I, for my part, altogether deny!” cried Leslie.

“Well,” I resumed, “but granting it for the moment, yet the important point is not the criterion, but the result.  It is a small thing to know in general terms (supposing even it were true that we do know it) that what we ought to seek is a preponderance of pleasure over pain; the whole problem is to discover, in innumerable detailed cases, wherein precisely the preponderance consists.  But this can only be learnt, if at all, by long and difficult, and, it may be, painful experience.  We do not really know, a priori, what things are pleasurable, in the extended sense which we must give to the word if the doctrine is to be at all plausible, any more definitely than we know what things are good.  And the Utilitarians by substituting the word Pleasure for the word Good, even if the substitution were legitimate, have not really done much to help us in our choice.”

“But,” he objected, “we do at least know what Pleasure is, even if we do not know what things are pleasurable.”

“And so I might say we do know what Good is, even if we do not know what things are good.”

“But we know Pleasure by direct sensation.”

“And so I might say we know Good by direct perception.”

“But you cannot define Good.”

“Neither can you define Pleasure.  Both must be recognised by direct experience.”

“But, at any rate,” he said, “there is this distinction, that in the case of Pleasure everyone does recognise it when it occurs; whereas there is no such general recognition of Good.”

“That,” I admitted, “may, perhaps, be true; I am not sure.”

“But,” broke in Leslie, “what does it matter whether it be true or no?  What has all this to do with the question?  It’s immaterial whether Pleasure or Good is the more easily and generally recognisable.  The point is that they are radically different things.”

“No,” objected Parry, “our point is that they are the same thing.”

“But I don’t believe you really think so, or that anyone can.”

“And I don’t believe that anyone cannot!”

“Do you mean to say that you really agree with Bentham that, quantity of pleasure being equal, pushpin is as good as poetry?”

“Yes; at least I agree with what he means, though the particular example doesn’t appeal to me, for I hardly know what either pushpin or poetry is.”

“Well then, let us take Plato’s example.  Do you think that, quantity of pleasure being equal, scratching oneself when one itches is as good as, say, pursuing scientific research.”