human duties
cannot be differentiated according to a difference of acts.

Obj. 2: Further, the active and the contemplative life differ
according to their acts, as stated above (Q. 179, A. 1). But the
distinction of duties seems to be other than the distinction of
lives. Therefore duties do not differ according to their acts.

Obj. 3: Further, even ecclesiastical orders, states, and grades
seemingly differ according to their acts. If, then, duties differ
according to their acts it would seem that duties, grades, and states
differ in the same way. Yet this is not true, since they are divided
into their respective parts in different ways. Therefore duties do
not differ according to their acts.

_On the contrary,_ Isidore says (Etym. vi, 19) that "_officium_
(duty) takes its name from _efficere_ (to effect), as though it were
instead of _efficium,_ by the change of one letter for the sake of
the sound." But effecting pertains to action. Therefore duties differ
according to their acts.

_I answer that,_ As stated above (A. 2), difference among the members
of the Church is directed to three things: perfection, action, and
beauty; and according to these three we may distinguish a threefold
distinction among the faithful. One, with regard to perfection, and
thus we have the difference of states, in reference to which some
persons are more perfect than others. Another distinction regards
action and this is the distinction of duties: for persons are said to
have various duties when they are appointed to various actions. A
third distinction regards the order of ecclesiastical beauty: and
thus we distinguish various grades according as in the same state or
duty one person is above another. Hence according to a variant text
[*The Septuagint] it is written (Ps. 47:4): "In her grades shall God
be known."

Reply Obj. 1: The material diversity of human acts is infinite. It is
not thus that duties differ, but by their formal diversity which
results from diverse species of acts, and in this way human acts are
not infinite.

Reply Obj. 2: Life is predicated of a thing absolutely: wherefore
diversity of lives results from a diversity of acts which are
becoming to man considered in himself. But efficiency, whence we have
the word "office" (as stated above), denotes action tending to
something else according to _Metaph._ ix, text. 16 [*Ed. Did. viii,
8]. Hence offices differ properly in respect of acts that are
referred to other per