According to Catholicism, is a Catholic priest's power of exorcism acceptable evidence of the Catholic Church's truth and validity of its claim to be the one true church?
Is a Catholic priest's power of exorcism acceptable evidence of the Catholic Church's truth and validity of its claim to be the one true church?
The short answer is no.
In his book An exorcist tells His Story, Fr Gabriele Amorth states the following:
Who Can Expel Demons?
"The Holy Spirit, with divine freedom, gives his charismas however and to whomever he pleases. These are not given to be the glory or benefit of the receiver but as a service to his brothers. Among these charismas is the power to liberate from evil spirits and to heal from illness. These gifts can be given to individuals and also to communities." (Page 155)
Fr Gabriele Amorth was exorcist for the Diocese of Rome prior to his death in 2016. He equally states that Christians of other denominations do expel demons during their prayers for liberation of a person from the grippes of Satan and his Legions. This admission is not limited to the Orthodox Churches, but also encompasses mainstream Protestant denominations. He does admit however that he was occasionally consulted by "exorcists" of other churches of particularly hard cases to liberate.
As Catholics, we have more available aides in combatting evil than our Protestant brethren.
In his book An Exorcist Tells His Story, Fr. Amorth lists the following prayers to help combat evil; however, Fr. Amorth and many other priests have stressed that the number one protection from evil is the Sacrament of Confession and the Sacrament of the Holy Eucharist. Often times people want esoteric rituals to deliver them from evil, when in reality what they need is to become right with God. Along with regular Confession and reception of the Holy Eucharist, these prayers should be coupled with Our Lord’s Prayer and the Prayer to St. Michael the Archangel. - 5 Prayers Recommended by an Exorcist to Combat Evil
The fact that within the Roman Catholic Rite only an authorized priest with the local bishop's permission may perform an exorcism (while using the Rituale Romanum) is a question of Canon Law and church disciple. Rome can change this rule at any moment if the need were serious enough. Some Eastern Orthodox exorcists are married deacons or subdeacons. The Orthodox have valid sacraments and priesthood!
The practice of exorcism was not confined to clerics in the early ages, as is clear from Tertullian (Apology 23; cf. On Idolatry 11) and Origen (Against Celsus VII.4). The latter expressly states that even the simplest and rudest of the faithful sometimes cast out demons, by a mere prayer or adjuration (Mark 15:17), and urges the fact as a proof of the power of Christ's grace, and the inability of demons to resist it.
Thus the Apostolic Constitutions (VIII.26) say expressly that "the exorcist is not ordained", i.e. for the special office of exorcist, but that if anyone possess the charismatic power, he is to be recognized, and if need be, ordained deacon or subdeacon. This is the practice which has survived in the Eastern Orthodox Church. - Catholic Encyclopedia
The ability to legitimately perform an exorcism is linked to jurisdiction according to Canon Law:
Can. 1172 §1. No one can perform exorcisms legitimately upon the possessed unless he has obtained special and express permission from the local ordinary.
§2. The local ordinary is to give this permission only to a presbyter who has piety, knowledge, prudence, and integrity of life.
The short answer is yes, most likely, Roman Catholics consider exorcism to be a fruit of the One True Church. To understand this, one has to understand the nature of a Catholic Priest. Let's start from the OP question and back into what it means.
Exorcism in the Catholic Church is considered a sacramental, which is distinguished from their seven sacraments. As such, there is no formula per se, but rather the exorcism depends on their being a valid and licit authorization and faith of said person. In other words, the exorcist must be a duly authorized priest.
So, with that in mind, the concept of valid priest in the Catholic Church is known by holy orders. Do other Churches have holy orders? Some claim to have it, but there are additional requirements as to validity. For example, as some define it, a tracing a physical lineage back to apostles, the intentional offering of bread and wine as a propitiatory sacrifice, and of course, submission to Peter's successor.
So, whether others attempt exorcisms, for the Catholic Church, it requires one of their duly ordained priests to produce its fruit.
When we think of exorcism, at least, when I do, I think of the "May the Power of Christ compels you" being uttered by an old Priest and a Young Priest. There is a bigger picture here, one that is often missed and overlooked when we consider what exorcism is. When Christ died on the Cross, he defeated through his sacrifice, the dominion of Satan, thereby exorcising Satan from Power in this world.
So is exorcism the Fruit of the Church? As with everything the Church teaches concerning sacraments and sacramentals, exorcism or indulgences or whatever you can think of, Christ did it first, and the Catholic by uniting themselves to the sufferings of Christ, share in that very same sacrifice.
We cast out Demons because Christ cast out demons, we offer our suffering for others, because Christ offered himself for others and so on.
Rather than saying "Exorcism is THE Fruit of the Church". I think it would be more accurate to say "Exorcism is A fruit of the Church" The True fruit is Christ himself, and the understanding of his salvific sacrifice and our participation in those sufferings as an Obedience of Faith.
I saw this Quote from Dostoevsky
“Of the pride of Satan what I think is this: it is hard for us on earth to comprehend it, and therefore it is so easy to fall into error and to share it, even imagining that we are doing something grand and fine.”
The devil fights hard for our destruction and even though he has already lost and knows it, destroying us brings him satisfaction. The Church fights the tricks of the devil by countering them with the Cross of Christ which is directly in opposition to those tricks, Humility rather than Pride, Charity rather than Covitiveness, self-denial rather than lust. When a Catholic embraces the sacraments, embraces the evangelical counsels or the cardinal virtues, it is manor of exorcising the fallen world from the temptations of the Satan.
So when for example a person says to me, "Christ did everything and there is nothing that I can do to be saved" I think to myself "The Power of Christ compels you" Just kidding, a little humor makes the medicine go down.