The word copia is a difficult one to translate. Its first meaning of "abundance" is liable, as Erasmus begins by showing, to be understood as mere verbosity.
"We see not a few mortals, who, striving to emulate this divine virtue with more zeal than success, fall into a feeble and disjointed loquacity, obscuring the subject and burdening the wretched ears of their hearers with a vacant mass of words and sentences crowded together beyond all possibility of enjoyment. And writers who have tried to lay down the principles of this art have gained no other result than to display their own poverty while expounding abundance."
He proposes to give only certain directions, and to illustrate them by formulas which may prove convenient to writers. Copia includes the ideas of richness and variety, but must avoid the errors of mere quantity and change. Not all fulness contributes to completeness of effect, and not all variation in style helps towards real illustration of the thought. Here, as elsewhere, we find Erasmus the true apostle of common-sense. After all, the purpose of rhetoric is primarily to say something worth saying, and to say it in such a way that it will commend itself to the reader. The purpose of these directions will therefore be to show how the essential point may be condensed into few words and yet nothing be left out, and how, on the other hand, one may expand into copia and yet have nothing in superfluity.
The first rule of the Copia verborum is
"that speech should be fitting [apta], good Latin, elegant and pure [pura].... What clothing is to the body, style is to the thought; for just as the beauty and dignity of the body are heightened or diminished by dress and care, so is thought by words. They are therefore greatly mistaken who think it makes no difference in what words a given thought is expressed if only it can be understood. So also there is the same principle in changing the dress and in varying the speech. It is our first care that our dress be neither mean, nor unsuited to our figure, nor of a wrong pattern. It would be a pity if a figure good in itself were to be spoiled by mean garments; it would be ridiculous if a man were to appear in public in woman's dress, and a disgrace if one were to be seen in a preposterous garb or with his clothes turned back side before.
"And so, if anyone tries to put on an affectation of copia before he has attained the purity of the Latin tongue, he is, in my judgment, no less ridiculous than a poor beggar, who, having not a single garment fit to wear, should thereupon change one set of rags for another and come out into the market-place to show off his beggary for wealth. And the oftener he should do this, would he not seem so much the more foolish? I think he would. And just as foolish are those who affect copia and yet cannot say in plain words what they want to say. As if they were ashamed to appear to stammer a little, they make their stammering only the more offensive in every possible way, as if they were on a wager with themselves to talk as barbarously as ever they can. I like to see a wealthy house furnished in great variety, but I want it all to be elegant and not to be filled up with articles of willow and fig-wood and vessels of Samian crockery. At a splendid banquet I like to have many kinds of food brought on, but who could bear it if anyone should serve a hundred sorts of food not one of which was fit to eat?"
Having thus admirably laid down the rule of moderation and good taste, Erasmus goes on to details. He shows what kinds of words are to be avoided and to what extent. His comments on the use of obscene words are interesting in view of the general practice of his time and, indeed, upon occasion, of his own practice. Certain words are obscene because they represent obscene things; others because they are twisted from their harmless meanings. "What then is the principle of obscenity?—nothing more nor less than the usage, not of anybody and everybody, but of those whose speech is correct." Of himself it must be said that in general he lived pretty well up to his principles. Where he offends in this respect it is generally in a kind of composition, as, for example, in many of the Colloquies, in which he simply lets himself go, producing his effect by a freedom which he carefully avoids in other forms of writing. He was, if one may say so, artistically obscene.
In spite of his admiration for pure Latinity, he does not hesitate to admit Greek words according to a rather dangerous canon. Greek words, he says, may be used when they are more significant, or shorter, or stronger, or more graceful, "for no Latin word can equal the grace of a Greek word." In short,
"whenever any certain appropriateness [commoditas] invites us we may properly interweave Greek with Latin, especially when we are writing to learned men; but when we are not so invited and deliberately weave a discourse that is half Latin and half Greek, this may perhaps be pardoned in youths who are training themselves to readiness in both languages, but for men this kind of display is, in my judgment, far from becoming and is as undignified as if one should write a book in prose and verse mixed up together, as, in fact, has been done by some learned men."
As to repetition, a trick of rhetoric often employed by Erasmus, he disapproves it in theory, but admits that it may be done "when the repetition helps the thought and when the weariness of it can be avoided by a certain variety." Cicero repeats, but he says "things similar, not the same things."