On the other hand, you may be skeptical, even if in principle you are open to the idea of extra-terrestrial life. Perhaps you view the vastness of the universe as probability for the existence of intelligent life on another planet, but doubt that anyone has developed the technology that would enable interstellar travel. In this case, UFO sightings, abduction stories and conspiracy theories probably wont persuade you to change your mind, since there may be plausible alternative explanations for all of these alleged phenomena.
The question, then, is on what basis should you believe the claim that extra-terrestrials have visited planet Earth? The only rational answer is to believe on the basis of credible evidence. As Carl Sagan said it, Extraordinary claims require extraordinary proof.
The same can be said of the claims of Christianity. For example, take the claim He is risen. This is an extraordinary claim, and no reasonable person ought to accept it without extraordinary proof. That doesnt mean we have to put our finger into the holes in Jesus hands in order to warrant belief. But it does mean we need more than hearsay. Providentially, we do have extraordinary evidence to back up this claim. An empty tomb that was under guard, hundreds of eyewitnesses, an otherwise improbable and inexplicable growth of Christianity, and no alternative explanation that has any plausibility whatsoever. In short, all the evidence points inescapably to one conclusion: Jesus of Nazareth died and rose again.
But what about the claim that Mary of Nazareth was conceived without sin? This too is an extraordinary claim and so it too requires extraordinary proof. But when we examine Scripture, we see no evidence that anyone thought Mary was conceived without sin nor any evidence that she was exempted from Adams curse. While there are traditions about her sanctity from the womb and throughout her life, the church is mostly silent on the issue of her conception until the middle ages, and even then most theologians either didnt see how it was possible for Mary to be conceived without sin or they outright denied it. The list of those opposed to the doctrine reads like a Whos Who of the medieval church: Bernard of Clairvaux, Thomas Aquinas, Bonaventure, and Anselm of Canterbury, just to name a few.
But then in the early 1300s, two English Franciscans (William of Ware and Duns Scotus) came up with a way to overcome the objections that the doctrine was a superstition (so Bernard) or that it could not be reconciled with the uniqueness of Christs redemption (so Aquinas). William used the argument from conveniens (Latin for convenience), which used the formula, potuit, decuit, fecit: God could do it, it is fitting that He would do it, therefore He did do it. Since Marys Immaculate Conception was both possible for God and fitting (on the grounds of the medieval supposition that never too much can be said of Mary), then it follows that God must have preserved Mary from contracting original sin, and so her conception was immaculate (stainless).
Scotus, for his part, theorized how God was able to preserve Mary from Original Sin without denying her need for redemption. The eternal God, who sees all things as present, must have applied the merits of the redemption to Mary before the redemption actually took place. Thus Marys redemption was by exemption. Instead of grace taking away the power of original sin after contracting it, she was graced by not contracting it in the first place.
Without commenting on the merits (or demerits) of such arguments, take a step back and notice what is going on. Despite the fact that Scripture and Tradition are at best silent on the issue, there is an undeniable desire on the part of many in the medieval church to believe in Mary's immaculate conception anyway. How does this differ from the UFO enthusiast looking for reasons to justify his belief in ETs? ETs could exist given the vastness of the universe, it is fitting that ETs would have visited Earth by now, given the age of the universe, therefore they did!
Surely it is within Gods power to preserve someone from original sin; no one disputes this. In fact, this would have been an extremely efficient way of redeeming the entire human racenot just Mary! But to date, there is no evidence that God has preserved anyone from original sin, not even Mary. (Jesus being God cannot contract sin, and so was not preserved from it.)
Unless of course you count alleged supernatural events such as apparitions as evidence. William of Ware put a lot of stock in the legend that Bernard of Clairvaux, soon after his death, appeared to a lay brother in a white garment with one small stain: his denial of the Immaculate Conception. St. Bridget of Sweden (d. 1373) claimed that Mary appeared to her and personally confirmed the Immaculate Conception. In 1830, just twenty-four years before the formal declaration of the Immaculate Conception as a must-believe dogma, St. Catherine Labouré claimed to have had a vision of Mary as the Immaculate Conception standing on the world with rays of light emanating from her hands to illuminate the earth. The vision was framed with the words, O Mary, conceived without sin, pray for us who have recourse to thee. This image is on the popular miraculous medal available at most Catholic kitsch stores.
Just as the medieval imagination was fertile ground for believing in visions as confirmation of doctrines, so the Romanticism of the late nineteenth century paved the way for sentiment to triumph over reason. On December 8, 1854, after having consulted with 603 bishops (56 of whom dissented), Pope Pius IX issued the bull, Ineffabilis Deus, which formally (and infallibly) defined the doctrine of the Immaculate Conception, and put the Catholic Church ® on a dogmatic path of no return. Not surprisingly, shortly after (1862) the definition a major Marian apparition took place that had the effect of confirming the doctrine in pious imagination. Near Lourdes in France, a girl of 14 named Bernadette Soubirous claimed that Mary appeared to her and said, I am the Immaculate Conception. The miraculous healings that followed could only serve to confirm the already existing belief.
The parallel to belief in ETs is instructive. Since the dawn of the space age and the realization that the stars are within our grasp, there has been a corresponding increase in UFO sightings, abduction stories and the like. Movies, science fiction novels, T.V., and the occasional Roswell documentary have collectively helped to solidify belief in ETs for those who already believe in them and predispose others to the idea that there just might be some intelligent life out there after all. When all of these phenomena are combined with a speculative theory that can explain how these phenomena might be possible, the result is fairly analogous to what has happened in Roman Catholicism with respect to Mary. The major difference, of course, is that no one is required to believe in ETs. But Roman Catholics are required to believe in the Immaculate Conception. (And the theory that Mary was abducted into Heaven, also known as the dogma of the Assumption.)
When the Protestant reformers began to jettison longstanding beliefs and practices that were not in accord with scripture, they did so with the conviction that extraordinary claims require extraordinary evidence and that only scripture could count as evidence that is extraordinary since only it is divinely inspired. Tradition, reason and even experience could also be brought to bear as confirmation for what is already found in scripture. But they could not substitute for a clear foundation in scripture. Jesus and the apostles relied on scripture for that kind of extraordinary evidence, Protestants think it only prudent to do the same. And so the process for accepting or rejecting a dogma of the church is rather straightforward. Justify the belief before you believe in it, and dont ask anyone to believe in it until you have.
Roman Catholicism has reversed this process any number of times throughout its history, especially since the Reformation, and has gone on to dogmatize beliefs that have little to no basis in scripture and sometimes little to no basis in tradition. Instead, Rome takes into consideration a hodgepodge of mutually reinforcing streams of evidence, such as liturgical practice, pious devotion, private revelations, the polling of bishops and speculative arguments about how fitting the doctrine is. And if this isnt enough, the matter can be settled definitively by an infallible papal decree, which means the doctrine must be held to be true simply by virtue of the fact that a pope intends to define the belief as a revealed dogma.
All too often in Roman Catholicism, the tail has wagged the dogor dogma in this case. Too often Rome has formally defined longstanding beliefs before it has produced good evidence for those beliefs. Would it not be more prudent to first examine whether there was sufficient proof for those beliefs to begin with?
Having studied historical and systematic theology in a Pontifical school of theology, I have witnessed this dog-wagging process over and over again: Begin first with the supposition that a belief is true (or at least accept the fact that youre stuck with it), and then work backwards to find out how the belief came about in the first place and how it coheres with the rest of the content of the faith. If you think the doctrine is defensible, all the better. If you dont, then try to salvage the doctrine by coming up with a more palatable interpretation.
For instance, Catholic theologian, Richard P. McBrien, says this of the Immaculate Conception:
The dogma of the Immaculate Conception teaches that Mary was exempt in a unique and exceptional way from the normal and the usual impact of sin, or, more positively, that she was given a greater degree of grace (i.e, God was more intensely present to her than to others) in view of her role as the God-bearer. So profound is her union with God in grace, in anticipation of her maternal function and in virtue of the redemptive grace of Christ, that she alone remains faithful to Gods will throughout her entire life. She is truly redeemed, but in an exceptional and unique manner. The Immaculate Conception shows that God can be, and is utterly gracious toward us, not by reason of our merits but by reason of divine love and mercy alone (Richard P. McBrien, Catholicism, [San Francisco: Harper, 1994], 1101)
McBrien is widely regarded by conservative Catholics as a dissenter, and we can see why. Although he claims to affirm the doctrine, he does so in a way that fails to affirm the traditional propositions of exemption from original sin and life long sinlessness. Instead, he interprets the dogma as an example of Gods graciousness in redemption apart from our works, as if the original intention behind the doctrine were to affirm a more or less Protestant principle of sola gratia.
For McBrien, the Immaculate Conception really tells us more about God than it does about Mary. In this way, the otherwise disagreeable aspects of the dogma are rendered innocuous and so, in good conscience, he can go about his merry way satisfied in the knowledge that the Immaculate Conception is really so much more than a mere affirmation of Marys sinlessness.
Id say this is fairly representative of how theology is done in many liberal Roman Catholic seminaries and theology schools. Virtually no importance is given to the idea of testing whether or not the doctrines of the Roman Catholic Church are true. Some of my systematic theology classes reminded me of the music appreciation class I had as an undergraduate: Sit back, listen and appreciate how the doctrines of the church play together like a symphony. When examined, I was not asked if I thought a belief was true or not; nor was I required to back up my beliefs with any kind of evidence. That would have been too much like the scholasticism of a bygone era. Instead, I was asked to name my favorite systematic theologians and articulate how they had integrated the dogmas of the church into their various systems.
In retrospect, I can see why Dogma Appreciation 101 was all my systematic theology courses could ever be. Once a doctrine is formally defined by Rome, then the truth of the matter is moot. Why argue against a doctrine if youre stuck with it? And why defend a doctrine that needs no defending? The only recourse is to appreciate it. If you happen to agree with the doctrine, all the better. If you do not, then try to make it say something more to your liking.
Once you are a member of a denomination that believes itself to be incapable of teaching error in matters of faith or morals, then theology can only ever be an exercise in appreciating infallible truths. There still may be room for synthetic efforts to articulate the dogmas of the church in an ever more fresh and meaningful way. But there can be no room for any true analytic efforts to evaluate whether or not the dogmas of the church are still worth believing in light of the evidence, or as is more often the case, the lack thereof.
Live long and prosper.