Taxonomy of the Potential Parts of Justice
As explained elsewhere, the potential parts of a cardinal virtue participate
in that virtue while falling short of satisfying its complete definition.
Justice, strictly speaking, is a virtue by which we render others their
lawful due according to equality, so that failure to do so is a fitting
matter for litigation and punishment in the eyes of those who care for
the good of the relevant community.
Consequently, all the potential parts of justice are similar to the
principal virtue in having to do with our treatment of others. However,
they fall short of satisfying the complete definition of justice in either
one of two ways:
- with respect to equality: This occurs when the person or persons
to whom we owe something are such they we cannot render them their due
according to equality. That is, we cannot give back to them anything close
to equal what they have given us by virtue of their generosity, example,
guidance, etc. There are three potential parts of justice that fall under
- religion (religio), which is the virtue by which we honor
God directly by appropriate interior and exterior acts.
- piety (pietas), which is the virtue by which we honor
our parents and our homeland.
- respect (observantia), which is the virtue by which we
render honor (dulia) and obedience (obedientia) to those
who are our superiors because of their virtue or because of their office.
- with respect to lawful due: Here St. Thomas distinguishes lawful
due (debitum legale), which is the object of justice proper,
from moral due (debitum morale), which has to do with the
rectitude of virtue.
- The relevant moral due is required to such a degree that virtue is
well-nigh impossible without it:
- What one owes to others, absolutely speaking: Truthfulness
(honesty) in self-representation.
- What one owes to others by way of compensation for things done to
one: Gratitude for good things and vindication (punishment)
for bad things.
- The relevant moral due is conducive to, but not absolutely required
for, virtue: Liberality, friendliness, etc. (How about niceness
or pleasantness, which often impresses us more than moral rectitude?)