In the laudable attempt of naturalizing philosophy at Rome, the difficulty which Lucretius had encountered, in embodying in Latin verse the precepts of Epicurus,--
"Propter egestatem linguæ rerumque novitatem,"
must have been almost as powerfully felt by Cicero. Philosophy was still little cultivated among the Romans; and no people will invent terms for thoughts or ideas with which it is little occupied. One of his letters to Atticus is strongly expressive of the trouble which he had in interpreting the philosophic terms of Greece in his native tongue(391). Thus, for example, he could find no Latin word equivalent to the { ~GREEK SMALL LETTER EPSILON WITH PSILI~}{ ~GREEK SMALL LETTER PI~}{ ~GREEK SMALL LETTER OMICRON~}{ ~GREEK SMALL LETTER CHI~}{ ~GREEK SMALL LETTER ETA~}, or that withholding of assent from all propositions, which the new Academy professed. The language of the Greeks had been formed along with their philosophy. Their terms of physics had their origin in the ancient Theogonies, or the speculations of the Milesian sage; and Plato informs us, that one might make a course of moral philosophy in travelling through Attica and reading the inscriptions engraved on the tombs, pillars, and monuments, erected in the earliest ages near the public ways and centre of villages(392). Hence, in Greece, words naturally became the apposite signs of speculative and moral ideas; but in Rome, a foreign philosophy had to be inculcated in a tongue which was already completely formed, which was greatly inferior in flexibility and precision to the Greek; and which, though Cicero certainly used some liberties in this respect, had too nearly reached maturity, to admit of much innovation. Its words, accordingly, did not always precisely express the subtle notions signified in the original language, whence there was often an appearance of obscurity in the idea, and of a defect in conclusions, drawn from premises which were indefinite, or which differed by a shade of meaning from those established in Greece.
Aware of this difficulty, and conscious, perhaps, that he possessed not precision and originality of thinking sufficient to recommend a formal treatise, Cicero adopted the mode of writing in dialogues, in which rhetorical diffuseness, and looseness of definition, might be overlooked, and in which ample scope would be afforded for the ornaments of language.