But every discourse which is concerned in the investigation of any matter, and which proceeds on any system and principle, ought first to establish the rule (as is done in lawsuits, where one proceeds according to set formulas), in order that it may be agreed between the parties to the discussion, what the subject of the discussion really is. This rule was approved by Epicurus, as it was laid down by Plato in his "Phædrus," and he considered that it ought to be adopted in every controversy. But he did not perceive what was the necessary consequence of it, for he asserts that the subject ought not to be defined; but if this be not done, it is sometimes impossible that the disputants should agree what the matter is that is the subject of discussion, as in this very case which we are discussing now, for we are inquiring into the End of Good. How can we know what the character of this is, if, when we have used the expression the End of Good, we do not compare with one another our ideas of what is meant by the End, and of what the Good itself is?
And this laying open of things covered up, as it were, when it is once explained what each thing is, is the definition of it; which you sometimes used without being aware of it; for you defined this very thing, whether it is to be called the End, or the extremity, or the limit, to be that to which everything which was done rightly was referred, and which was itselfnever referred to anything. So far was very well said; and, perhaps, if it had been necessary, you would also have defined the Good itself, and told us what that was; making it to be that which is desirable by nature, or that which is profitable, or that which is useful, or that which is pleasant: and now, since you have no general objections to giving definitions, and do it when you please, if it is not too much trouble, I should be glad if you would define what is pleasure, for that is what all this discussion relates to.
As if, said he, there were any one who is ignorant what pleasure is, or who is in need of any definition to enable him to understand it better.
I should say, I replied, that I myself am such a man, if I did not seem to myself to have a thorough acquaintance with, and an accurate idea and notion of, pleasure firmly implanted in my mind. But, at present, I say that Epicurus himself does not know, and that he is greatly in error on this subject; and that he who mentions the subject so often ought to explain carefully what the meaning of the words he uses is, but that he sometimes does not understand what the meaning of this word pleasure is, that is to say, what the idea is which is contained under this word.