Catholic doctrine of the Immaculate Conception of the Virgin Mary was formulated with absolute precision and for all time in the Bull of Pope Pius IX, Ineffabilis Deus, on December 8, 1854. The essential words of the definition are these:
The most blessed Virgin Mary, in the first instant of her conception, was by the singular grace and privilege of almighty God, in view of the merits of Jesus Christ, Savior of the human race, preserved immune from all stain of original sin. This doctrine is revealed by God and therefore must be firmly and constantly believed by all the faithful. (1)
As is evident from the terms of this proposition, there are two constitutive elements in the definition: 1. a declaration of the privilege itself of the Immaculate Conception; 2. a statement of the certitude of that privilege.
1. Declaration of the Privilege
In order the better to understand what is contained within this singular privilege of Christ’s Mother, one may examine the component parts, or “causes” of the Immaculate Conception. These are:
a) Material cause, or subject. Obviously, the subject of the Immaculate Conception is the person of the Blessed Virgin Mary, considered in the first instant of her conception in the womb of her mother. A human begins to be, in the true sense, at the moment the soul is created by God and infused into the fetus, and this is the moment of animation. That is called Mary’s “passive conception.” Passive conception is the terminus of the parents’ generative act, which act is, by way of contradistinction, called “active conception.” (2)
Before the human fetus is informed by a rational soul, the conception is known as “inchoate,” while from the instant of the animation of the fetus, the conception is “consummated.” (3) It is solely when the fetus is consummately conceived that a person has come into being. At precisely what stage of fetal development the soul is created and infused by God has always provided theologians with material for subtle discussion, but modern writers commonly favor the opinion that it takes place at the very first moment of fecundation. The definition of the Immaculate Conception offers no intimation as to the official teaching of the Church on the point.
Surely it would be untenable to argue in favor of any sanctification of Mary prior to the animation of the fetus, for until the moment of the substantial union between soul and body there is not yet a person, and hence no possible subject of grace. Only a rational person can be sanctified. The privilege accordingly affects uniquely the person of the Virgin, and not merely the soul nor merely the virginal body of the Mother of God. The initial sanctity of Mary concerns exclusively her personal conception achieved in sanctifying grace. Her freedom from the stain of all sin is identified with her being and her personality. (4)
b) Formal cause, or object. This aspect of the privilege of the Immaculate Conception concerns the fact of the preservation of the Virgin from all stain of original sin. The definition directly denies that she contracted the guilt of Adam’s curse, and so indirectly it affirms, because of the diametrical opposition between sin and grace, that she possessed sanctifying grace from the first instance of her personal existence. Original sin, according to the settled teaching of the Church, is the deprivation of grace inflicted upon the posterity of Adam as a consequence of his personal sin; it is a radical enmity between a sinful mankind and the Creator. (5) Therefore, directly to exempt Mary from this essential effect of original sin is indirectly to affirm that she enjoyed an original sanctity through grace, with its accompanying adoptive filiation as a child of God. She was ever on terms of perfect friendship with God. (6)