A. How Baptism can have a Definition

9. In the solution of this question, one can speak similarly to the way spoken above in d.1 nn.181-187 about the definition of a sacrament.

For if one lays down from the usage of speakers the meaning of the word ‘baptism’, namely that baptism signifies a certain special sacrament so that, if baptism signifies cleansing (as the baptisms, that is the cleansings, of bodies and vessels was among the Jews), then a sacrament of baptism (understanding this in transitive sense) is that which signifies a special sacrament. This is plain both from specifying the signification and the effect signified (namely purifying the soul from original sin), and from specifying the foundation of this sort of signification and relation - it is plain, I say, from this supposition how baptism can have a definition. For since what is definable should be a positive being, per se one, real, and common (as maintained above, d.1 n.187), then baptism cannot be a pure non-being (as something impossible is).

10. The proof follows the way used above about a sacrament [d.1 n.181]:

For the idea of baptism is not in itself false, since there is no repugnance in any sensible thing or things being instituted by God for signifying, as an effect, the cleansing of the soul from sin.

11. Nor is baptism a pure non-being, as is a negation or privation - as is plain [d.1 n.182].

12. Baptism is also, second, something per se one as to what it principally per se signifies, which is the sort of relation a sign has to the sort of thing signified [d.1 n.183].

13. Nor is it an objection that baptism connotes its correlative and foundation, because thus also does any relation signify; nor is it an objection that many things are connoted in the foundation, because (as said above, d.1 n.199) a single relation of reason can be founded in any number of things distinct in reality. However, such connotation can very well prevent a thing’s having a definition in the primary sense; for nothing has a definition in the primary sense save substance, which is not defined by anything added on, either in the way the correlative is added in the definition of a correlative, or as a subject is added in the definition of an accident. Now many things have a definition but not in the primary sense, as is plain from Metaphysics 7.4.1030b4-7.

14. Only the third condition, then, namely that the definable thing must be a real being [d.1 n.184], prevents the sacrament of baptism having an altogether perfect definition; but it has a definition in the way that second intentions or any relations of reason are defined, because (as far as concerns an intellect possessed of science through definition) it is a definition in the way that a definition is that which a quiddity in reality corresponds to [d.1 nn.200-204].