What is a Sacrament?

After considering those things that concern the mystery of the incarnate Word, we must consider the sacraments of the Church which derive their efficacy from the Word incarnate Himself. First we shall consider the sacraments in general; secondly, we shall consider specially each sacrament.

Concerning the first our consideration will be fivefold: (1) What is a sacrament? (2) Of the necessity of the sacraments; (3) of the effects of the sacraments; (4) Of their cause; (5) Of their number.

Under the first heading there are eight points of inquiry:

(1) Whether a sacrament is a kind of sign?

(2) Whether every sign of a sacred thing is a sacrament?

(3) Whether a sacrament is a sign of one thing only, or of several?

(4) Whether a sacrament is a sign that is something sensible?

(5) Whether some determinate sensible thing is required for a sacrament?

(6) Whether signification expressed by words is necessary for a sacrament?

(7) Whether determinate words are required?

(8) Whether anything may be added to or subtracted from these words?