Because one man is better disposed than another to attain to the mean of virtue which is defined by right reason
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic virtue reason
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“because the nature of virtue consists in a maximum. If, however, we consider virtue on the part of the subject, it may then be greater or less, either in relation to different times, or in different men. Because one man is better disposed than another to attain to the mean of virtue which is defined by right reason; and this, on account of either greater habituation, or a better natural disposition, or a more discerning judgment of reason, or again a greater gift of grace, which is given to each one "according to the measure of the giving of Christ,"” source