Objection 1. It would seem that drink is not the matter proper to sobriety. For it is written (Romans 12:3): "Not to be more wise than it behooveth to be wise, but to be wise unto sobriety." Therefore sobriety is also about wisdom, and not only about drink.
Objection 2. Further, concerning the wisdom of God, it is written (Wisdom 8:7) that "she teacheth sobriety [Douay: 'temperance'], and prudence, and justice, and fortitude," where sobriety stands for temperance. Now temperance is not only about drink, but also about meat and sexual matters. Therefore sobriety is not only about drink.
Objection 3. Further, sobriety would seem to take its name from "measure" ['Bria,' a measure, a cup; Cf. Facciolati and Forcellini's Lexicon]. Now we ought to be guided by the measure in all things appertaining to us: for it is written (Titus 2:12): "We should live soberly and justly and godly," where a gloss remarks: "Soberly, in ourselves"; and (1 Timothy 2:9): "Women... in decent apparel, adorning themselves with modesty and sobriety." Consequently it would seem that sobriety regards not only the interior man, but also things appertaining to external apparel. Therefore drink is not the matter proper to sobriety.
On the contrary, It is written (Sirach 31:32): "Wine taken with sobriety is equal life to men; if thou drink it moderately, thou shalt be sober."
I answer that, When a virtue is denominated from some condition common to the virtues, the matter specially belonging to it is that in which it is most difficult and most commendable to satisfy that condition of virtue: thus fortitude is about dangers of death, and temperance about pleasures of touch. Now sobriety takes its name from "measure," for a man is said to be sober because he observes the "bria," i.e. the measure. Wherefore sobriety lays a special claim to that matter wherein the observance of the measure is most deserving of praise. Such matter is the drinking of intoxicants, because the measured use thereof is most profitable, while immoderate excess therein is most harmful, since it hinders the use of reason even more than excessive eating. Hence it is written (Sirach 31:37-38): "Sober drinking is health to soul and body; wine drunken with excess raiseth quarrels, and wrath and many ruins." For this reason sobriety is especially concerned with drink, not any kind of drink, but that which by reason of its volatility is liable to disturb the brain, such as wine and all intoxicants. Nevertheless, sobriety may be employed in a general sense so as to apply to any matter, as stated above (123, 2; 141, 2) with regard to fortitude and temperance.
Reply to Objection 1. Just as the material wine intoxicates a man as to his body, so too, speaking figuratively, the consideration of wisdom is said to be an inebriating draught, because it allures the mind by its delight, according to Psalm 22:5, "My chalice which inebriateth me, how goodly is it!" Hence sobriety is applied by a kind of metaphor in speaking of the contemplation of wisdom.
Reply to Objection 2. All the things that belong properly to temperance are necessary to the present life, and their excess is harmful. Wherefore it behooves one to apply a measure in all such things. This is the business of sobriety: and for this reason sobriety is used to designate temperance. Yet slight excess is more harmful in drink than in other things, wherefore sobriety is especially concerned with drink.
Reply to Objection 3. Although a measure is needful in all things, sobriety is not properly employed in connection with all things, but only in those wherein there is most need for a measure.
Source: Summa Theologica (New Advent)