Summa Theologica, by St. Thomas Aquinas, [1947], at sacred-texts.com
In due sequence we must consider the vices that are opposed to religion. First we shall consider those which agree with religion in giving worship to God; secondly, we shall treat of those vices which are manifestly contrary to religion, through showing contempt of those things that pertain to the worship of God. The former come under the head of superstition, the latter under that of irreligion. Accordingly we must consider in the first place, superstition and its parts, and afterwards irreligion and its parts.
Under the first head there are two points of inquiry:
(1) Whether superstition is a vice opposed to religion?
(2) Whether it has several parts or species?
Objection 1: It would seem that superstition is not a vice contrary to religion. One contrary is not included in the definition of the other. But religion is included in the definition of superstition: for the latter is defined as being "immoderate observance of religion," according to a gloss on Col. 2:23, "Which things have indeed a show of wisdom in superstition." Therefore superstition is not a vice contrary to religion.
Objection 2: Further, Isidore says (Etym. x): "Cicero [*De Natura Deorum ii, 28] states that the superstitious were so called because they spent the day in praying and offering sacrifices that their children might survive [superstites] them." But this may be done even in accordance with true religious worship. Therefore superstition is not a vice opposed to religion.
Objection 3: Further, superstition seems to denote an excess. But religion admits of no excess, since, as stated above (Q[81], A[5], ad 3), there is no possibility of rendering to God, by religion, the equal of what we owe Him. Therefore superstition is not a vice contrary to religion.
On the contrary, Augustine says (De Decem Chord. Serm. ix): "Thou strikest the first chord in the worship of one God, and the beast of superstition hath fallen." Now the worship of one God belongs to religion. Therefore superstition is contrary to religion.
I answer that, As stated above (Q[81], A[5]), religion is a moral virtue. Now every moral virtue observes a mean, as stated above (FS, Q[64], A[1]). Therefore a twofold vice is opposed to a moral virtue. One by way of excess, the other by way of deficiency. Again, the mean of virtue may be exceeded, not only with regard to the circumstance called "how much," but also with regard to other circumstances: so that, in certain virtues such as magnanimity and magnificence; vice exceeds the mean of virtue, not through tending to something greater than the virtue, but possibly to something less, and yet it goes beyond the mean of virtue, through doing something to whom it ought not, or when it ought not, and in like manner as regards other circumstances, as the Philosopher shows (Ethic. iv, 1,2,3).
Accordingly superstition is a vice contrary to religion by excess, not that it offers more to the divine worship than true religion, but because it offers divine worship either to whom it ought not, or in a manner it ought not.
Reply to Objection 1: Just as we speak metaphorically of good among evil things---thus we speak of a good thief---so too sometimes the names of the virtues are employed by transposition in an evil sense. Thus prudence is sometimes used instead of cunning, according to Lk. 16:8, "The children of this world are more prudent [Douay: 'wiser'] in their generation than the children of light." It is in this way that superstition is described as religion.
Reply to Objection 2: The etymology of a word differs from its meaning. For its etymology depends on what it is taken from for the purpose of signification: whereas its meaning depends on the thing to which it is applied for the purpose of signifying it. Now these things differ sometimes: for "lapis" [a stone] takes its name from hurting the foot [laedere pedem], but this is not its meaning, else iron, since it hurts the foot, would be a stone. In like manner it does not follow that "superstition" means that from which the word is derived.
Reply to Objection 3: Religion does not admit of excess, in respect of absolute quantity, but it does admit of excess in respect of proportionate quantity, in so far, to wit, as something may be done in divine worship that ought not to be done.
Objection 1: It would seem that there are not various species of superstition. According to the Philosopher (Topic. i, 13), "if one contrary includes many kinds, so does the other." Now religion, to which superstition is contrary, does not include various species; but all its acts belong to the one species. Therefore neither has superstition various species.
Objection 2: Further, opposites relate to one same thing. But religion, to which superstition is opposed, relates to those things whereby we are directed to God, as stated above (Q[81], A[1]). Therefore superstition, which is opposed to religion, is not specified according to divinations of human occurrences, or by the observances of certain human actions.
Objection 3: Further, a gloss on Col. 2:23, "Which things have . . . a show of wisdom in superstition," adds: "that is to say in a hypocritical religion." Therefore hypocrisy should be reckoned a species of superstition.
On the contrary, Augustine assigns the various species of superstition (De Doctr. Christ. ii, 20).
I answer that, As stated above, sins against religion consist in going beyond the mean of virtue in respect of certain circumstances (A[1]). For as we have stated (FS, Q[72], A[9]), not every diversity of corrupt circumstances differentiates the species of a sin, but only that which is referred to diverse objects, for diverse ends: since it is in this respect that moral acts are diversified specifically, as stated above (FS, Q[1], A[3]; FS, Q[18], AA[2],6).
Accordingly the species of superstition are differentiated, first on the part of the mode, secondly on the part of the object. For the divine worship may be given either to whom it ought to be given, namely, to the true God, but "in an undue mode," and this is the first species of superstition; or to whom it ought not to be given, namely, to any creature whatsoever, and this is another genus of superstition, divided into many species in respect of the various ends of divine worship. For the end of divine worship is in the first place to give reverence to God, and in this respect the first species of this genus is "idolatry," which unduly gives divine honor to a creature. The second end of religion is that man may be taught by God Whom he worships; and to this must be referred "divinatory" superstition, which consults the demons through compacts made with them, whether tacit or explicit. Thirdly, the end of divine worship is a certain direction of human acts according to the precepts of God the object of that worship: and to this must be referred the superstition of certain "observances."
Augustine alludes to these three (De Doctr. Christ. ii, 20), where he says that "anything invented by man for making and worshipping idols is superstitious," and this refers to the first species. Then he goes on to say, "or any agreement or covenant made with the demons for the purpose of consultation and of compact by tokens," which refers to the second species; and a little further on he adds: "To this kind belong all sorts of amulets and such like," and this refers to the third species.
Reply to Objection 1: As Dionysius says (Div. Nom. iv), "good results from a cause that is one and entire, whereas evil arises from each single defect." Wherefore several vices are opposed to one virtue, as stated above (A[1]; Q[10], A[5]). The saying of the Philosopher is true of opposites wherein there is the same reason of multiplicity.
Reply to Objection 2: Divinations and certain observances come under the head of superstition, in so far as they depend on certain actions of the demons: and thus they pertain to compacts made with them.
Reply to Objection 3: Hypocritical religion is taken here for "religion as applied to human observances," as the gloss goes on to explain. Wherefore this hypocritical religion is nothing else than worship given to God in an undue mode: as, for instance, if a man were, in the time of grace, to wish to worship God according to the rite of the Old Law. It is of religion taken in this sense that the gloss speaks literally.