St. Thomas Aquinas, although recognized as one of the greatest theologians of all time, did manage, however, to fall into error. Please understand that the purpose of showing this is not to demonize St. Thomas, nor is it to suggest he was a heretic, but simply to point out the importance, as Catholics, to measure all things against the infallible judgment of the Church, even though they may come from holy Doctors such as St. Thomas, who although a Catholic genius, was not infallible.
Here are a few errors contained in his Summa Theologica:
Summa, Tertia Pars, Q. 27, Art. 2, Reply to Obj. 2: “For Christ did not contract original sin in any way whatever, but was holy in His very Conception, according to Luke 1:35: "The Holy which shall be born of thee, shall be called the Son of God." But the Blessed Virgin did indeed contract original sin, but was cleansed therefrom before her birth from the womb.”
This is in direct opposition (and is therefore overruled by) the later definition of the Immaculate Conception, by Pope Pius IX.
Pope Pius IX, Ineffabilis Deus (The Immaculate Conception), 1854 , ex cathedra: “We declare, pronounce, and define that the doctrine which holds that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful.”
Summa, Tertia Pars, Q. 68. Art. 2, Reply to Obj. 3: “The sacrament of Baptism is said to be necessary for salvation in so far as man cannot be saved without, at least, Baptism of desire; "which, with God, counts for the deed”.”
This teaching states that a person may be saved without receiving baptism in water. This is contrary to the dogma that a person must be born again of water and the spirit and that one must be part of the faithful for salvation. A catechumen is not part of the faithful, nor did he ever join the Church before the end of his life if he died unbaptized.
Pope Innocent III, Fourth Lateran Council, 1215, ex cathedra: “There is indeed one universal church of the faithful, outside of which nobody at all is saved…”
Pope Paul III, Council of Trent, Session VII, Canons on Baptism, Canon II, AD 1547, ex cathedra: “If any one saith, that true and natural water is not of necessity for baptism, and, on that account, wrests, to some sort of metaphor, those words of our Lord Jesus Christ; Unless a man be born again of water and the Holy Ghost; let him be anathema.”
Summa, Supplement (Appendix 1), Q. 1, Art. 2, Reply to Obj 5: "Reply to Objection 5. Although unbaptized children are separated from God as regards the union of glory, they are not utterly separated from Him: in fact they are united to Him by their share of natural goods, and so will also be able to rejoice in Him by their natural knowledge and love."
St. Thomas teaches above that infants who have died without baptism will be united to God and be able to rejoice in Him, despite the dogmatic truth that such children are in fact condemned to the fires of hell.
Pope Eugene IV, Council of Florence, 1439, ex cathedra: "But the souls of those who depart this life in actual mortal sin, or in original sin alone, go down straightaway to hell to be punished, but with unequal pains."
Unbaptized infants die with original sin alone. People who argue that the "unequal pains" means a place with no fire, are contradicting the following decree:
Pope Eugene IV, Council of Florence, 1442, ex cathedra: "ALL those who are outside the Catholic Church, not only pagans but also Jews or heretics and schismatics, cannot share in eternal life and will go into the everlasting fire which was prepared for the devil and his angels, unless they are joined to the Catholic Church before the end of their lives"
Unbaptized infants are indeed among ALL those outside the Church, for only water baptism makes a person a member of the Church, therefore they go into the fire, though certainly not the hottest fires, which are reserved for the obstinate enemies of God.
The Summa Theologica, though mostly reliable, is an excellent example of why correct theology regards the solemn definitions of the Extraordinary Magisterium as the standard against which all doctrine is to be measured, which is also attested to by Pope Benedict XIV:
Pope Benedict XIV, Apostolica Constitutio, #6, June 26, 1749: "The Church’s judgment is preferable to that of a Doctor renowned for his holiness and teaching."
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