“For the honor of the Holy and Undivided Trinity, for the glory and adornment of the Virgin Mother of God, for the exaltation of the Catholic faith and the increase of the Christian religion, We declare, pronounce, and define, by the authority of our Lord Jesus Christ, of the blessed Apostles Peter and Paul, and Our own, that the doctrine which holds that the most Blessed Virgin Mary, in the first instant of her conception, was, by the singular grace and privilege of God, in view of the merits of Christ Jesus, the Saviour of the human race, preserved free from every stain of original sin, has been revealed by God and is therefore to be firmly and constantly believed by all the faithful.”
-Pope Pius IX, December 8th, 1854
Properly speaking, of course, the Feast of the Immaculate Conception is our national feast day. American Catholics ought to celebrate it with bonfires and fireworks and all the trappings that go into the Fourth of July and then some. Our Lady of the Immaculate Conception is our patroness (and I believe specifically requested to be so named in one of her apparitions), and we should always remember that.
Dogmas always come with a whole host of implications, just as any number implies by its very being every conceivable and inconceivable formula for achieving it. But, by my own understanding (so, written under correction), there are two especially major implications of the doctrine for the modern world. The first is a reiteration of the fact of original sin. When it is said that Mary was preserved ‘by the singular grace and privilege of God,’ it is as much to say that no other person has been so favoured. As such, we’re reminded that we are a fallen race, tainted by sin from the first moment of our being, in our very nature, and consequently in need of ‘the merits of Christ Jesus, the Saviour of the human race,’ (from whom also comes that same ‘singular grace’, but more on that below). The ideas of a perfectible human society and utopian progress through the elimination of bad social structures is thereby rejected utterly; it can’t happen. Christ alone is the saviour of mankind, because mankind lives under the shadow of original sin, all apart from this one exception, who is herself preserved by the merits of her son.
The other is a reiterated rejection of the Protestant idea of salvation; that we are not made pure, but merely covered and excused by the merits of Christ. By the shining example of the Immaculate Conception is shown that Christ’s redemptive power is redemptive indeed and works a real change in the person being saved, so that they are not simply excused or covered over, but in fact made holy. What once was tainted and sinful is transformed to being truly “white as snow.”
Why does that matter? Because the Protestant view tends to disassociate the divine and the human. If a person cannot be made truly holy, but only have holiness ascribed to him, than human actions can’t matter because they can’t change the state of a person’s righteousness. And, consequently, there is a hard compartmentalization of the spiritual and the earthly; man cannot actually become holy, nor can any of his institutions be divinely ordained. Consequently, religion is left a purely personal matter and everything we meet on earth a purely practical one.
But that Our Lady was Immaculately Conceived shows that this is not the case, that souls redeemed are in fact made holy. But if they are made holy in fact, then salvation itself is a matter of fact and not attribution, meaning that the spiritual and earthly actually overlap (I mean, the Incarnation itself shows that, but this reinforces it), subjecting all human actions and institutions to the call to holiness. That we can become holy means that we have duty to become so.
To sum up, the Immaculate Conception reminds us that man cannot perfectly himself, but requires a saviour, and, on the other hand, that this salvation, being redeemed in fact and thus imposes real obligations upon us. Or, to put it together, the Immaculate Conception recalls to us that, contra modernism, faith is not to be relegated to a sideshow.