VANA OSSERVANZA. — This is one of the forms of non-cultic superstition, in which practices unsuitable to the purpose one wishes to achieve are performed with a superstitious intention.
Such practices include the art of acquiring knowledge without studying, for example, through the use of certain words, figures, special prayers, and fasts; the art of healing by disproportionate means, such as the use of prayers, adjurations, and exorcisms, attributing to them an infallible efficacy ex opere operato; and the art of protecting oneself from evils and dangers through the use of lucky charms, amulets, etc. V. demon.
Indeed, whoever, in order to obtain a particular effect, employs a vain and useless means—that is, one which neither nature, nor God, nor the Church has ordained to produce that effect—can expect such a result only from the demon.
The morality of V. o. is generally inferred from the agent’s intention itself, from the effects he foresaw, and from the dangers of sin to which he exposed himself. If the observances involve an invocation of, or an explicit pact with, the demon, there is evidently grave sin (cf. Deut. 18, 10-11; Lev. 19, 31; 20, 27), also because no temporal benefit can compensate for the spiritual harm resulting from demonic invocation (Sum. Theol., 2a-2ae, q. 95, a. 2 e 4). Even when there is no explicit pact, if one knowingly and superstitiously employs a means unsuitable to a particular end, one commits in itself a grave sin, because one implicitly desires diabolical intervention. Nevertheless, in this case one is generally excused from grave guilt, since the act is usually performed out of mere curiosity, simplicity, or ignorance.