Q: In another question you said that St. Thomas Aquinas explained why Mary submitted to a Mosaic purification ritual even though she was sinless, something which you said he and virtually everyone in his day accepted. But I have heard a Protestant apologist repeatedly say that Aquinas rejected the Immaculate Conception. What’s the deal?
A: What the Protestant apologist said is a classic example of a half-truth. Evangelicals often use the fact that Aquinas (unlike others of his age) did not believe that Mary was entirely sanctified from the moment of her conception to imply that she committed actual, personal sin–as Protestants assert. However, nothing could be further from the truth. Even though Aquinas did not claim that Mary was sanctified from the moment of her conception, he did claim that she was sanctified before her birth, and so never committed personal sin (for unborn children commit no personal sin; cf. Rom. 9:11).
For a Protestant to knowingly push this claim is deceptive on three fronts:
1) It suggests that Aquinas’s views ought to be held to (on those rare occasions) when he disagrees with what the Church has since established as true, but the views of no one theologian, even an Aquinas, may be held in preference to what the Church later establishes. Aquinas’s views–as he himself would insist–simply cease to count as evidence concerning what a Catholic should believe once the Church has infallibly determined otherwise.
2) The fact is that Aquinas did hold to Mary’s entire personal sinlessness, which is what Protestants really object to. They are not concerned about what Aquinas was looking at–whether she was free from each and every stain of original sin during a window of time prior to her birth. That is a trivial matter to them compared to the question of whether Mary committed actual, personal sin during her life. That is what they are obsessed about and which will get them hopping up and down issuing charges of heresy, claiming that a sinless life makes Mary out to be God (as if it would make us God when we have been entirely sactified and are leading totally sinless lives). When Protestants say that Aquinas didn’t believe in the Immaculate Conception but fail to say that he believed in her sinless life, they are picking at something that is from their position a nit and omitting the fact that Aquinas is not on their in the thing which really concerns them.
3) Since Protestants have identified the doctrine of the Immaculate Conception with the doctrine of Mary’s personal sinlessness, it is deceptive of them to say that Aquinas did not believe in the Immaculate Conception because this will imply to their audience–and to anyone else who doesn’t have a good grasp on the doctrine–that he believed Mary sinned, which is simply not true. They will thus mislead their audience into thinking Aquinas said something he didn’t, and to do that knowingly is deception, plain and simple.
In any event, here is what Aquinas said (Summa Theologiae III:27:4):
“I answer that, God so prepares and endows those, whom He chooses for some particular office, that they are rendered capable of fulfilling it, according to 2 Cor. 3:6: ‘(Who) hath made us fit ministers of the New Testament.’ Now the Blessed Virgin was chosen by God to be His Mother. Therefore there can be no doubt that God, by His grace, made her worthy of that office, according to the words spoken to her by the angel (Lk. 1:30,31): ‘Thou hast found grace with God: behold thou shalt conceive,’ etc. But she would not have been worthy to be the Mother of God, if she had ever sinned. First, because the honor of the parents reflects on the child, according to Prov. 17:6: ‘The glory of children are their fathers’: and consequently, on the other hand, the Mother’s shame would have reflected on her Son. Secondly, because of the singular affinity between her and Christ, who took flesh from her: and it is written (2 Cor. 6:15): ‘What concord hath Christ with Belial?’ Thirdly, because of the singular manner in which the Son of God, who is the ‘Divine Wisdom’ (1 Cor. 1:24) dwelt in her, not only in her soul but in her womb. And it is written (Wis. 1:4): ‘Wisdom will not enter into a malicious soul, nor dwell in a body subject to sins.’
“We must therefore confess simply that the Blessed Virgin committed no actual sin, neither mortal nor venial; so that what is written (Cant 4:7) is fulfilled: ‘Thou art all fair, O my love, and there is not a spot in thee,’ etc. “
Thus you should never tolerate someone to say that Aquinas endorsed the idea that Mary was sinful. He absolutely and unequivocally did not, and you should ask any Protestant who says this whether he has actually read what Aquinas said on the subject or whether he is repeating erroneous claims made in anti-Catholic sources. If he is doing the latter, he is repeating gossip. If he is doing the former, and really does know what Aquinas said, then he is being deceptive.