If PD3 and much of Epicurus' discussion about "the limit of pleasure" (extending into the references to "absence of pain") is a response and refutation of earlier logical objections to viewing pleasure as the highest good, it would be expected that this argument should be found in a number of ancient writers. The purpose of this thread is to collect those instances and look for more, which will assist everyone in consideration of this issue. (Note: A recent example of this argument is here.)
As a start we can find two very clear instances: the first and primary in Plato's Philebus. We can also find the argument stated very clearly in Seneca, who of course post-dates Epicurus, but who would probably the first to say that he did not claim originality, and that his own ideas reflected those of the earlier philosophers. Plus, Seneca formulates the argument with crystal clarity: "The ability to increase is proof that a thing is imperfect.”
I will list those two here in this post, and keep this first post up to date as others can find and suggest more. Please keep this question in mind and when you come across other instances of this argument in the future, please post them to this thread.
The argument that "pleasure is insatiable" is probably a subset and closely related to this same argument, so references to that argument would also be welcome in this thread. Simply stating that pleasure is insatiable does not give a complete argument, however, but I bet there are instances where that argument is made in more expansive form that would definitely be relevant here. A similar observation goes for the "purity" argument, in which smaller quantities of something that is pure are asserted to be superior to larger quantities of adulterated versions of the same thing.
I will update these with better hyperlinks but here are the two I have already collected in my "Full Cup / Fullness of Pleasure" article:
2. Seneca (Letters)
Here is an excerpt from Philebus as a finding aid to the full discussion where the argument can be researched:
SOCRATES: I omit ten thousand other things, such as beauty and health and strength, and the many beauties and high perfections of the soul: O my beautiful Philebus, the goddess, methinks, seeing the universal wantonness and wickedness of all things, and that there was in them no limit to pleasures and self-indulgence, devised the limit of law and order, whereby, as you say, Philebus, she torments, or as I maintain, delivers the soul. — What think you, Protarchus?
SOCRATES: Have pleasure and pain a limit, or do they belong to the class which admits of more and less?
PHILEBUS: They belong to the class which admits of more, Socrates; for pleasure would not be perfectly good if she were not infinite in quantity and degree.
SOCRATES: Nor would pain, Philebus, be perfectly evil. And therefore the infinite cannot be that element which imparts to pleasure some degree of good. But now — admitting, if you like, that pleasure is of the nature of the infinite — in which of the aforesaid classes, O Protarchus and Philebus, can we without irreverence place wisdom and knowledge and mind? And let us be careful, for I think that the danger will be very serious if we err on this point.
PHILEBUS: You magnify, Socrates, the importance of your favourite god.
SOCRATES: And you, my friend, are also magnifying your favourite goddess; but still I must beg you to answer the question.
SOCRATES: And whence comes that soul, my dear Protarchus, unless the body of the universe, which contains elements like those in our bodies but in every way fairer, had also a soul? Can there be another source?
PROTARCHUS: Clearly, Socrates, that is the only source.
SOCRATES: Why, yes, Protarchus; for surely we cannot imagine that of the four classes, the finite, the infinite, the composition of the two, and the cause, the fourth, which enters into all things, giving to our bodies souls, and the art of self-management, and of healing disease, and operating in other ways to heal and organize, having too all the attributes of wisdom; — we cannot, I say, imagine that whereas the self-same elements exist, both in the entire heaven and in great provinces of the heaven, only fairer and purer, this last should not also in that higher sphere have designed the noblest and fairest things?
PROTARCHUS: Such a supposition is quite unreasonable.
SOCRATES: Then if this be denied, should we not be wise in adopting the other view and maintaining that there is in the universe a mighty infinite and an adequate limit, of which we have often spoken, as well as a presiding cause of no mean power, which orders and arranges years and seasons and months, and may be justly called wisdom and mind?
… … PROTARCHUS: Most justly.
Seneca’s Letters – Book I – Letter XVI: This also is a saying of Epicurus: “If you live according to nature, you will never be poor; if you live according to opinion, you will never be rich.” Nature’s wants are slight; the demands of opinion are boundless. Suppose that the property of many millionaires is heaped up in your possession. Assume that fortune carries you far beyond the limits of a private income, decks you with gold, clothes you in purple, and brings you to such a degree of luxury and wealth that you can bury the earth under your marble floors; that you may not only possess, but tread upon, riches. Add statues, paintings, and whatever any art has devised for the luxury; you will only learn from such things to crave still greater. Natural desires are limited; but those which spring from false opinion can have no stopping point. The false has no limits.
Seneca’s Letters – To Lucilius – 66.45: “What can be added to that which is perfect? Nothing otherwise that was not perfect to which something has been added. Nor can anything be added to virtue, either, for if anything can be added thereto, it must have contained a defect. Honour, also, permits of no addition; for it is honourable because of the very qualities which I have mentioned. What then? Do you think that propriety, justice, lawfulness, do not also belong to the same type, and that they are kept within fixed limits? The ability to increase is proof that a thing is still imperfect.”“THE ABILITY TO INCREASE IS PROOF THAT A THING IS IMPERFECT.”
Please add your suggestions for other instances to this thread. I am sure that there are likely to be others out there, especially in Cicero and likely numerous Stoic references.