Accident a term of philosophy used to express that which is merely adventitious to a substance, and not essential to it; e.g. roundness is an accident of any body, since it is a body all the same, whether it be round or square. In theology this word is used in connection with the Roman doctrine of transubstantiation, which teaches that the accidents of the bread and wine in the holy Eucharist continue to subsist without a subject: "Accidentia autem sine subjecto in eodem [sacramento] subsistunt" (Aquinas, Opuscula, p. 57). And the catechism of the council of Trent speaks in these terms: "Tertium restat, quod in hoc Sacramento maximum atque mirabile videatur, panis videlicet et vini species in hoc Sacramento sine aliqua re subjecta constare" (Par. 2, No. 44). In defense of this doctrine, Roman writers argue thus: If the eucharistic accidents have any subject, that subject must be either (1) the matter of bread, or (2) the surface of the Lord's body, or (3) the air and other corpuscles contained in the pores, etc., of the matter, whatever it is, which, by God's appointment, continue to subsist after the destruction of the matter, so as to produce the same sensations. Now (1) they cannot have the matter of bread for their subject, because that matter no longer subsists, and is changed into the body of Jesus Christ; (2) they cannot have the surface of the Lord's body for their subject, because it is only present in an invisible manner; and (3) the air cannot be the subject of these accidents, because the same accidents, numero, cannot pass from one subject to another; and because, further, the air cannot at the same time be the substance of its own proper attributes and of those of bread (Thomas Aquinas, par. 3, qu. 77, art. 1, in corp). They argue further, that the contrary doctrine, viz., that they are not really the accidents of bread and wine, but only appear such to us, destroys the nature and idea of a sacrament and of transubstantiation. That a sacrament, by its very nature, is essentially a sensible sign, not only in relation to ourselves, but in itself, i.e., in the language of the schools, not only ex parte nostri, but exparte sui; and that, consequently, if all that there is real and physical in the eucharistic accidents consists in this, that God causes them to produce in us, after consecration, the same sensations which the bread did previously, the sacrament is no longer a sensible sign, exparte sui, in itself, but only ex parte nostri; and, therefore, when God ceases to produce such sensations in us, as, for instance, when the consecrated host is locked up in the pyx, it is no longer a sacrament. They argue also, that to hold that they are not pure, or absolute accidents, destroys equally the nature of transubstantiation, because (1) transubstantiation is a real conversion of the bread and wine into the body and blood of Jesus Christ. Now, in every conversion there must be something common to both substances remaining the same after the change that it was before, else it would be simply a substitution of one thing for another. As then, in the holy eucharist, the substances of bread and wine do not remain after consecration, it follows that what does remain is the pure accidents. (2) They who oppose the doctrine of absolute accidents teach that one body differs from another only in the different configuration of its parts; and that wherever there is the same configuration of parts, there is the same body; and wherever there are the same sensations produced, there is also the same arrangements of parts to produce them. If this be so, since, in the holy eucharist, the same sensations are produced after the consecration as before, there must be the same configuration of parts after consecration as before, or the same body; in other words, there is no change, no transubstantiation. — Landon, Eccl. Dictionary, s.v. SEE TRANSUBSTANTIATION.