Thomas Aquinas did not believe that Mary’s conception was immaculate. In fact he was quite clear about the matter in his Compendium of Theology:

As appears from the foregoing exposition, the Blessed Virgin Mary became the mother of God’s Son by conceiving of the Holy Spirit. Therefore it was fitting that she should be adorned with the highest degree of purity, that she might be made conformable to such a Son. And so we are to believe that she was free from every stain of actual sin-not only of mortal sin but of venial sin. Such freedom from sin can pertain to none of the saints after Christ, as we know from 1 John 1:8: “If we say that we have no sin we deceive ourselves, and the truth is not in us.” But what is said in the Canticle of Canticles 4:7, “You are all fair, my love, and there is no spot in you,” can well be understood of the Blessed Virgin, Mother of God.

Mary was not only free from actual sin, but she was also, by a special privilege, cleansed from original sin. She had, indeed, to be conceived with original sin, inasmuch as her conception resulted from the commingling of both sexes. For the privilege of conceiving without impairment of virginity was reserved exclusively to her who as a virgin conceived the Son of God. But the commingling of the sexes which, after the sin of our first parent, cannot take place without lust, transmits original sin to the offspring. Likewise, if Mary had been conceived without original sin, she would not have had to be redeemed by Christ, and so Christ would not be the universal redeemer of men, which detracts from His dignity. Accordingly we must hold that she was conceived with original sin, but was cleansed from it in some special way.

Some men are cleansed from original sin after their birth from the womb, as is the case with those who are sanctified in baptism. Others are reported to have been sanctified in the wombs of their mothers, in virtue of an extraordinary privilege of grace. Thus we are told with regard to Jeremiah: “Before I formed you in the womb of you mother I knew you; and before you came forth out of the womb I sanctified you” (Jer. 1:5). And in Luke 1:15 the angel says of John the Baptist: “He shall be filled with the Holy Spirit even from his mother’s womb.” We cannot suppose that the favor granted to the precursor of Christ and to the prophet was denied to Christ’s own mother. Therefore we believe that she was sanctified in her mother’s womb, that is, before she was born.

Yet such sanctification did not precede the infusion of her soul. In that case she would never have been subject to original sin, and so would have had no need of redemption. For only a rational creature can be the subject of sin. Furthermore, the grace of sanctification is rooted primarily in the soul, and cannot extend to the body except through the soul. Hence we must believe that Mary was sanctified after the infusion of her soul.

But her sanctification was more ample than that of others who were sanctified in the wombs of their mothers. Others thus sanctified in the womb were, it is true, cleansed from original sin; but the grace of being unable to sin later on, even venially, was not granted to them. The Blessed Virgin Mary, however, was sanctified with such a wealth of grace that thenceforth she was preserved free from all sin, and not only from mortal sin, but also from venial sin. Moreover venial sin sometimes creeps up on us unawares, owing to the fact that an inordinate motion of concupiscence or of some other passion arises prior to the advertence of the mind, yet in such a way that the first motions are called sins. Hence we conclude that the Blessed Virgin Mary never committed a venial sin, for she did not experience such inordinate motions of passion. Inordinate motions of this kind arise because the sensitive appetite, which is the subject of these passions, is not so obedient to reason as not sometimes to move toward an object outside the order of reason, or even, occasionally, against reason; and this is what engenders the sinful impulse. In the Blessed Virgin, accordingly, the sensitive appetite was rendered so subject to reason by the power of the grace which sanctified it, that it was never aroused against reason, but was always in conformity with the order of reason. Nevertheless she could experience some spontaneous movements not ordered by reason.

In our Lord Jesus Christ there was something more. In Him the lower appetite was so perfectly subject to reason that it did not move in the direction of any object except in accord with the order of reason, that is, so far as reason regulated the lower appetite or permitted it to go into action of its own accord. So far as we can judge, a characteristic pertaining to the integrity of the original state was the complete subjection of the lower powers to reason. This subjection was destroyed by the sin of our first parent, not only in himself, but in all the others who contract original sin from him. In all of these the rebellion or disobedience of the lower powers to reason, which is called concupiscence (fomes peccati), remains even after they have been cleansed from sin by the sacrament of grace. But such was by no means the case with Christ, according to the explanation given above.

In the Blessed Virgin Mary, however, the lower powers were not so completely subject to reason as never to experience any movement not preordained by reason. Yet they were so restrained by the power of grace that they were at no time aroused contrary to reason. Because of this we usually say that after the Blessed Virgin was sanctified concupiscence remained in her according to its substance, but that it was shackled.

– Thomas Aquinas, Compendium of Theology, Part 1, Chapter 224

I’d like to draw the reader’s attention to a few interesting things:

1) Thomas Aquinas clearly and repeatedly denies any immaculate conception:

• She had, indeed, to be conceived with original sin, inasmuch as her conception resulted from the commingling of both sexes.
• Likewise, if Mary had been conceived without original sin, she would not have had to be redeemed by Christ, and so Christ would not be the universal redeemer of men, which detracts from His dignity.
• Accordingly we must hold that she was conceived with original sin, but was cleansed from it in some special way.
• Therefore we believe that she was sanctified in her mother’s womb, that is, before she was born.Yet such sanctification did not precede the infusion of her soul. In that case she would never have been subject to original sin, and so would have had no need of redemption.
• Furthermore, the grace of sanctification is rooted primarily in the soul, and cannot extend to the body except through the soul. Hence we must believe that Mary was sanctified after the infusion of her soul.
• In the Blessed Virgin Mary, however, the lower powers were not so completely subject to reason as never to experience any movement not preordained by reason. Yet they were so restrained by the power of grace that they were at no time aroused contrary to reason. Because of this we usually say that after the Blessed Virgin was sanctified concupiscence remained in her according to its substance, but that it was shackled.

This is an abundantly clear, reasoned position from Thomas Aquinas against the idea of any immaculate conception of Mary. I mention this not to suggest that Thomas Aquinas’ reasoning is correct, or that I agree with his position.

I raise it to point out that Pius IX’s claims regarding history are patently untrue:

And indeed, illustrious documents of venerable antiquity, of both the Eastern and the Western Church, very forcibly testify that this doctrine of the Immaculate Conception of the most Blessed Virgin, which was daily more and more splendidly explained, stated and confirmed by the highest authority, teaching, zeal, knowledge, and wisdom of the Church, and which was disseminated among all peoples and nations of the Catholic world in a marvelous manner — this doctrine always existed in the Church as a doctrine that has been received from our ancestors, and that has been stamped with the character of revealed doctrine. For the Church of Christ, watchful guardian that she is, and defender of the dogmas deposited with her, never changes anything, never diminishes anything, never adds anything to them; but with all diligence she treats the ancient documents faithfully and wisely; if they really are of ancient origin and if the faith of the Fathers has transmitted them, she strives to investigate and explain them in such a way that the ancient dogmas of heavenly doctrine will be made evident and clear, but will retain their full, integral, and proper nature, and will grow only within their own genus — that is, within the same dogma, in the same sense and the same meaning.

– Pius IX, Ineffabilis Deus (1854), Are we really supposed to believe that Thomas Aquinas, the foremost theologian of the middle ages, was unaware of “this doctrine” which allegedly “always existed in the Church as a doctrine that has been received from our ancestors, and that has been stamped with the character of revealed doctrine”? Or are we simply to suppose that Thomas Aquinas thought it was a revealed doctrine, but rejected it anyway?

2) Thomas Aquinas realized the significance of 1 John 1:8

1 John 1:8: “If we say that we have no sin we deceive ourselves, and the truth is not in us.”

Thomas Aquinas tried to get around this by essentially making it forward-looking only.

But Thomas Aquinas has not rightly recognized that this was nothing unique to the New Testament era:

Romans 3:9-12
What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin; as it is written, There is none righteous, no, not one: there is none that understandeth, there is none that seeketh after God. They are all gone out of the way, they are together become unprofitable; there is none that doeth good, no, not one.

That is also a New Testament text, but Paul relies on the Old Testament text to prove his point.

Psalm 14:3 They are all gone aside, they are all together become filthy: there is none that doeth good, no, not one.

As also elsewhere:

Proverbs 20:9 Who can say, I have made my heart clean, I am pure from my sin?

Accordingly, Paul concludes:

Romans 3:23 For all have sinned, and come short of the glory of God;

Paul does not exclude Mary from this, just as the fathers did not:

Tertullian (c. 160-c. 220):

Thus some men are very bad, and some very good; but yet the souls of all form but one genus: even in the worst there is something good, and in the best there is something bad. For God alone is without sin; and the only man without sin is Christ, since Christ is also God.

ANF: Vol. III, A Treatise on the Soul, Chapter 41.

Basil of Caesarea (AD. 329-379):

When thou hast blessed the Lord out of Scripture according to thy power, and hast sent up thy praise to Him, then begin to humble thyself and say, ‘I am not worthy, O Lord, to speak before Thee, because I am a sinner.’ Even though thou knowest nothing evil of thyself, thou must speak so; for none is without sin, but God only.

Greek text: Ὅταν δὲ δοξολογήσῃς ἀπὸ τῶν Γραφῶν, ὡς δύνασαι, καὶ ἀναπέμψῃς αἶνον πρὸς τὸν Θεὸν, τότε ἄρχου μετὰ ταπεινοφρόσύνης, καὶ λέγε. Ἐγὼ μὲν, Κύριε, οὐκ εἰμὶ ἄξιος ἐπὶ σοῦ φθέγξασθαι, διότι σφόδρα ἁμαρτωλὸς τυγχάνω. Κὰν μὴ σύνοιδάς τι σεαυτῷ φαῦλον, οὕτω χρὴ σε λέγειν. Οὐδεὶς γὰρ ἀναμάρτητος εἰ μὴ μόνος ὁ Θεός.

Constitutiones Monasticae, Caput I. §3. PG 31:1329; for translation, see Richard Travers Smith, The Fathers for English Readers: St. Basil the Great (New York: Poit, Young and Company, 1879), pp. 145-146.

Ambrose (c. 339-97):

No Conception is without iniquity, since there are no parents who have not fallen.

Latin text: Nec conceptus iniquitatis exsors est, quoniam et parentes non carent lapsu.

Prophetae David ad Theodosium Augustum, Caput XI, PL 14:873; for translation, see I. D. E. Thomas, The Golden Treasury of Patristic Quotations (Oklahoma City: Hearthstone Publishing, 1996), p. 258.

Augustine (354-430):

In a similar way we can speak of our Lord’s “sin,” meaning what sin brought about, because he assumed his flesh from that very stock that by sin had deserved death. To put it briefly: Mary, descended from Adam, died because of sin. Adam died because of sin, and the Lord’s flesh, derived from Mary, died to abolish sins.

Latin text: Sic ergo peccatum Domini, quod factum est de peccato, quia inde carnem assumpsit, de massa ipsa quae mortem meruerat ex peccato. Etenim ut celerius dicam, Maria ex Adam mortua propter peccatum, Adam mortuus propter peccatum, et caro Domini ex Maria mortua est propter delenda peccata.

In Psalmum XXXIV, Sermo II, §3, PL 36:335; Works of Saint Augustine, John E. Rotelle, O.S.A., ed., Expositions of the Psalms 33-50, Part 3, Vol. 16, trans. Maria Boulding, O.S.B. (Hyde Park: New City Press, 2000), Exposition 2 of Psalm 34 (35), p. 62.

Fulgentius, bishop of Ruspe (c. 467-532):

For the flesh of Mary, which had been conceived in iniquities in the usual manner, was the flesh of sin which begot the Son of God in the likeness of the flesh of sin…

Latin Text: Caro quippe Mariae, quae in iniquitatibus humana fuerat solemnitate concepta, caro fuit utique peccati, quae Filium Dei genuit in similitudinem carnis peccati.

Epistola XVII, Cap. VI, §13, PL 65:458.

Clement of Alexandria (ca. 150 – 215):

Now, O you, my children, our Instructor is like His Father God, whose son He is, sinless, blameless, and with a soul devoid of passion; God in the form of man, stainless, the minister of His Father’s will, the Word who is God, who is in the Father, who is at the Father’s right hand, and with the form of God is God. He is to us a spotless image; to Him we are to try with all our might to assimilate our souls. He is wholly free from human passions; wherefore also He alone is judge, because He alone is sinless.

(The Paedogogus, Book I, Chapter 2)

Origen (ca. 185 – 232):

And as it is necessary that that which is mortal should die, and it is impossible but that it should die, and as it must needs be that he who is in the body should be fed, for it is impossible for one who is not fed to live, so it is necessary and impossible but that occasions of stumbling should arise, since there is a necessity also that wickedness should exist before virtue in men, from which wickedness stumbling-blocks arise; for it is impossible that a man should be found altogether sinless, and who, without sin, has attained to virtue.

(Commentary on Matthew, Book XIII, Section 23)

Cyprian of Carthage (died 258):

Let us then acknowledge, beloved brethren, the wholesome gift of the divine mercy; and let us, who cannot be without some wound of conscience, heal our wounds by the spiritual remedies for the cleansing and purging of our sins. Nor let any one so flatter himself with the notion of a pure and immaculate heart, as, in dependence on his own innocence, to think that the medicine needs not to be applied to his wounds; since it is written, “Who shall boast that he has a clean heart, or who shall boast that he is pure from sins? ” [Proverbs 20:9] And again, in his epistle, John lays it down, and says, “If we say that we have no sin, we deceive ourselves, and the truth is not in us.” But if no one can be without sin, and whoever should say that he is without fault is either proud or foolish, how needful, how kind is the divine mercy, which, knowing that there are still found some wounds in those that have been healed, even after their healing, has given wholesome remedies for the curing and healing of their wounds anew!

(Treatise 8: On Works and Alms, Section 3)

Cyril of Jerusalem (ca. 315 – 386):

For we tell some part of what is written concerning His loving-kindness to men, but how much He forgave the Angels we know not: for them also He forgives, since One alone is without sin, even Jesus who purges our sins. And of them we have said enough.

(Catechetical Lectures, Lecture 2, Section 10)

Rufinus (ca. 345 – 410):

For He alone it is Who has not sinned, and has taken away the sins of the world. For if by one man death could enter into the world, how much more by one man, Who was God also, could life be restored!

(Commentary on the Apostles’ Creed, Section 25)

John Cassian (ca. 360 – 435):

Full well, when he says that He was sent in the flesh, does he exclude for Him sin of the flesh: for he says “God sent His own Son in the likeness of the flesh of sin,” in order that we may know that though the flesh was truly taken, yet there was no true sin, and that, as far as the body is concerned, we should understand that there was reality; as far as sin is concerned, only the likeness of sin. For though all flesh is sinful, yet He had flesh without sin, and had in Himself the likeness of sinful flesh, while He was in the flesh but He was free from what was truly sin, because He was without sin: and therefore he says: “God sent His own Son in the likeness of sinful flesh.”

(On the Incarnation, Book IV, Chapter 3)

Gregory the Great (ca. 540 – 604):

Moreover, since no one among men in this world is without sin (and what else is sinning but flying from God?), I say confidently that this my daughter also has some sins. Wherefore, that she may perfectly satisfy her mistress, that is eternal Wisdom, let her, who fled alone, return with many. For the guilt of turning away will be imputed to no one who in returning brings back gain.

(Registrum Epistolarum, Book VII, Letter 30: To Narses)

Sedrach (10th or 11th Century)

Sedrach says to God: O Lord, You alone are sinless and very compassionate, having compassion and pity for sinners, but your divinity said: I am not come to call the righteous but sinners to repentance.

And the Lord said to Sedrach: Do you not know, Sedrach, that the thief was saved in one moment to repent? Do you not know that my apostle and evangelist was saved in one moment? “Peccatores enim non salvantur,” for their hearts are like rotten stone: these are they who walk in impious ways and who shall be destroyed with Antichrist.

Sedrach says: O my Lord, You also said: My divine spirit entered into the nations which, not having the law, do the things of the law. So also the thief and the apostle and evangelist and the rest of those who have already got into your Kingdom. O my Lord; so likewise do You pardon those who have sinned to the last: for life is very toilsome and there is no time for repentance.

(Apocalypse of Sedrach, Section 15)

What are we to conclude? Was Gregory the Great just forgetting about Mary – did that slip Augustine’s mind too?

But if you will conclude that Aquinas and all the fathers quoted above were simply forgetful and absent-minded. And even if you will read the clear teaching of Paul and John regarding the universal sinfulness of mankind so as to be forward-looking only – still consider this:

Mark 10:18 And Jesus said unto him, Why callest thou me good? there is none good but one, that is, God.

Will anyone dare to suggest that Jesus forgot about his own mother?

-TurretinFan

P.S. My friend Dr. White will be debating this very topic of the Immaculate conception (and alleged sinlessness of Mary) with Christopher Ferrara in a few hours. May God be glorified by the debate, and may many come to see the truth that Mary properly had Jesus as her Savior.