Quibus enim oculis animi intueri potuit vester Plato fabricam illam tanti operis, qua construi a deo atque aedificari mundum facit; quae molitio, qua… - Cicero

Epicurus however is a more troublesome opponent, because he is a combination of two different sorts of pleasure, and because besides himself and his friends there have been so many later champions of his theory, which somehow or other enlists the support of that least competent but most powerful adherent, the general public.

Now, what is the quality to look out for as a warrant for the stability and permanence of friendship? It is loyalty. Nothing that lacks this can be stable. We should also in making our selection look out for simplicity, a social disposition, and a sympathetic nature, moved by what moves us. These all contribute to maintain loyalty. You can never trust a character which is intricate and tortuous. Nor, indeed, is it possible for one to be trustworthy and firm who is unsympathetic by nature and unmoved by what affects ourselves. We may add, that he must neither take pleasure in bringing accusations against us himself, nor believe them when they are brought. All these contribute to form that constancy which I have been endeavouring to describe. And the result is, what I started by saying, that friendship is only possible between good men.

"I conclude, then, that the plea of having acted in the interests of a friend is not a valid excuse for a wrong action. . . . We may then lay down this rule of friendship — neither ask nor consent to do what is wrong. For the plea "for friendship's sake" is a discreditable one, and not to be admitted for a moment."