Why Does Cicero use the Third-Person Singular Instead of the Plural Form?

Question

Cicero, de Oratore (2.25.108):

"...in quibus hoc praecipit ratio et doctrina ut vis eius rei, quam definias sic exprimatur ut neque absit quicquam neque supersit,"

"...on which occasions reason and learning direct, that the whole force of the thing which you define should be expressed in such a manner, that there be nothing omitted or superfluous;" (Attalus).

The line:

"...in quibus hoc praecipit ratio et doctrina..."

might be better translated as:

"...on which occasions reason and learning direct this...";

assuming that "hoc" = "this" is the neuter, accusative singular form. (The English translation omitted to translate "hoc".)

If (nominative, feminine nouns) "ratio" and "doctrina" are working together, as it were, in equal measure, to do the directing, why is the third-person singular, "praecipit", used and not the expected third-person plural, "praecipiunt"--"they (both) are directing (this)"? Does one noun take priority over another?

Answer 1

Cicero does this more than once. In addition to what you found in De oratore, we have

ea ratio atque doctrina
(also in De oratore)

and

ratio et doctrina praescripserit
(in De natura deorum)

indicating that Cicero does see ratio et doctrina as a single entity. This appears to be a case of hendiadys, using what is grammatically two entities for what is semantically a single entity.

You may well replace "reason and learning" with "learned reasoning" or some other phrase in the same direction, to make it clearer that it acts as a single entity. Or you can consider translating it with a single word like "wisdom" which captures both reason and education. This also emphasizes Cicero's use of them as a pair, not as the mere sum of the two words.

When translating to English, you can phrase it in a way that makes the English natural and conveys the same idea. Translation is about ideas, not about words, especially if you do not need to satisfy an examiner of your skill. (That's why I disagree on your stating that the English translation omitted to translate hoc; such a pronoun was simply not needed to phrase the thought in English.)