I've talked to a few people who advocate practical arguments for Christianity, of the sort which say that one chooses Christianity out of practical need instead of merely theoretical reasons. I will assess three different ways of going about this, and how I think they fail: (1) Simple pragmatism, (2) Christian-specific pragmatism, and (3) Live-option pragmatism. However, I do think that I see some individuals who practically choose Christianity without theoretical justification, and so I will end by going through different kinds of these practical individuals and in what ways they may be justified.
All of this applies to intellectuals, to those who have the luxury and responsibility to think through the issues involved; I don't think that easy answers can be given for the person in the pew who works 12 hour days with several kids to raise, nor that I have the experience to say anything about them. I think outright fideism is either a separate topic (and as I've noted in the past, I question the morality of the fideistic line), or a version of (3); I haven't decided yet.
First, simple pragmatism. By this I simply mean arguments which have the form: (a) We have a need, (b) Christianity meets this need, (c) Therefore we should become Christians. Pascal's wager is a version of this: we face the possibility of Hell if we are atheists, Christianity gives (approximately) equivalent or better rewards than atheism whether it is right or wrong, therefore the best choice is Christianity. As I've noted many times in conversations, these arguments simply don't take seriously the fact that there are other religions. They get their force from positing a simple and complete disjunction between Christianity and Atheism/Secular Humanism; if this really were the case, they would work. But there are Islam, Buddhism, Hinduisms, etc. as well, and therefore there are other options to solving the problem than Christianity. Pascal's Wager would need to take into account the Islamic hell, the Buddhism never-ending hells, Madhvacharya's hell in Dvaita Hinduism, and so on; the wager looks to be rather less compelling a case for Christianity at this point. I have seen one article which addressed this problem for Pascal's Wager, but its conclusion was that we should choose a non-sectarian religion and not Christianity. Other practical arguments seem to suffer the same fate: there is a universal problem (or at least general; I'll use universal throughout, but as long as it applies to people from different belief systems then my criticism stands) which is given a particular solution, which happens to be only one solution amongst many. Therefore, the proposed solution in all probability doesn't work, which is a problem since working would be kind of the point of a pragmatic argument. The next two options will try to either narrow the problem or the solution set to solve this issue. If the narrowing attempts are unsuccessful, then the attempt to find a working solution to one's problem in Christianity fails as well.
Maybe the problem is Christian-specific, and so Christianity is really the only solution. The practical argument would not be given to a Buddhist, but only to someone within a Christian community using Christian standards. Since Christian notions of Hell, sin, and other problems to be avoided are specifically Christian, no other religion could satisfy them. This is Christian-specific pragmatism. But in any case where one is arguing for the practical use of Christianity to solve another's problem, the other is not already a Christian; if one is merely trying to exhort the other toward a more authentic Christian life, this is another matter entirely. So one must already be using a concept which is not merely Christian-specific; some sense of sin and despair which one could recognize in oneself even without believing in the Triune God, for example (this is to leave aside the extent to which even within the tradition, the concept of, say, sin is equivocal). But once the problem is more universal, then the solution must match the problem, and it is doubtful that Christianity is the only solution once again. People read Kierkegaard as Buddhists or generic Theists and make sense out of the problem of despair, while either reworking his solution of faith as a generic faith or dismissing it as too facile an answer to the problem. There could be a person's own idiosyncratic problem which can only be solved within Christianity, and therefore merely a particular problem which can take a particular solution. However, this is a separate issue; my hunch is that (i) there can be no arguments for or against such a position since, as idiosyncratic, it is not open for public discussion, and (ii) one is taking on far more commitment within Christianity and its universal claims than would be warranted; one's personal problems should not lead to statements about the salvation of humanity (but is this any different from any pragmatic argument? something doesn't seem quite right with this criticism of mine; maybe it is an example of the next category? another possibility to explore?).
Maybe Christianity is not the only solution to the problem, but maybe it is the only live option which one can take; this is the thorniest way of approaching the argument, so please bear with me. If one is in a Christian culture, maybe converting to Buddhism or Islam is not really practical, and so even if there are technically other solutions, they don't need to be considered. With only one option left, one has only one particular solution even if the problem is more universal. This may have applied when there truly was little knowledge of other religions and no avenue for practice, but most of us know of these other religions and could find a community around ourselves. We could convert, even if this may come at a cost. We may narrow down our live options because this suits our lives better, but it seems like this can only happen because we do not comprehend what is at stake. Our salvation (from whatever to whatever) is at stake, as individuals and as within the communities we influence around us; it is not merely an ethical and individual choice, but a profoundly political one as well, shaping the lives of others to possibly a huge extent, given how people are influenced by role models and concrete examples as much as anything else. Given the shear scope of the problem and the ultimate value of its solution (or non-solution, if Zen happens to be right), how can we ever be justified in artificially limiting our options? (but more on that in a moment). Just because one has invested oneself in Christianity up until this point, just because one's family and friends are all Christians, just because one's life will be more difficult as a minority, does not come close to legitimately limiting the options once the problem is looked at clearly. To say that Christianity is one's only live option, then, would seem to be a point about one's own flawed way of looking at the world, which would shirk responsibility and be impractical for truly attaining one's ends (since religion, or at least plenty of views we call religion, is about our ultimate end). Also, even as a pragmatic solution, it just stuns me that anyone could place their salvation (and the matter of salvation across humanity) in the hands of what their utterly contingent (and often unquestioning) culture considers to be spiritually relevant; and what else is a live option in many cases, other than what the culture has constrained?
But the last argument is certainly weak; we can pick out people who are Christians for practical reasons who do not seem to be such monstrous blockheads as my evaluation would have them out to be. It seems to me that there are three categories (or maybe better: archetypes) of those who choose Christianity for practical reasons, or at least that the following three categories are useful for getting into the problem whether or not they are either precise or exhaustive.
First, we have finite time and energy, and can only work at keeping so many options live. One could look at other religions, but one also has other similarly important things to do, like feeding the widows and orphans. These other things to do both take away one's time for delving into the theoretical questions in greater detail, and demand some standpoint from which one works (one serves humanity because of Christ's example, for example). In this case, especially if one keeps thinking through the questions within the religion insofar as one has the opportunity, there seems to me to be no question in that such a person is justified. This may require that one is focused on the ends of others which are generally considered to be important, and important enough to avoid looking to one's own salvation (maybe love really is about giving up one's own concern about salvation for the good of others?); being an Evangelical missionary to take care of the salvation of others, when justified purely through pragmatic means, I think would fit in one of the next groups (though I am thinking through that one).
Second, some people make the practical decision for a given religion themselves, but are tolerant of others' choices in the matter. They recognize the tenuousness of their decision, and even though they may choose recklessly, they do not call others to do so. They listen and take the time to understand those who disagree with them. Given the political nature of our choices as well as the individual problems which would arise, I cannot say that I can agree with such a position, but these people are at least much nicer to live with than others and do genuinely display virtues in their lives. This kind of life would lead me to think that such people have some justification in believing they way they do, though the broader implications in leading people away from the truth if they are wrong would lead me to think that they have some culpability as well.
Third, some people make their practical decisions and expect that others should do the same. They keep themselves ignorant of other views which could challenge their own, which would reveal the fragility of their decisions; they do not take the trouble to sincerely understand other perspectives. They may adopt a dogmatic stance within their religion and come up with fideistic epistemologies to lock themselves and others in. I have no great fondness for this type of decision, as I'm sure everyone is aware; they not only harm themselves, but do great harm to others who would find such a life attractive, and to communities in which people do not have the luxury of thinking through their beliefs. Not only do they mislead others directly in the case that they are wrong, but this sort of non-self-critical attitude prevents them and their communities from recognizing other problems (such as racism and sexism). In another way of looking at matters, this is the ancient problem of rhetoric vs. philosophy played out within religion, with the present category representing the rhetoricians.
Maybe one could fit somewhere in between the second and third kinds of believers some other category, but I'll leave this as an exercise to the reader. Also, figures such as Reb Saunders in Chaim Potok's The Chosen come to mind, as dogmatic individuals who are nevertheless virtuous human beings who have had to take a rigid stance in order to keep their communities alive and healthy; they have given their lives over to others, and their pragmatic stance on religion is necessitated from this. But I take it that such an individual would be exceptional, although this raises significant political issues for my criticism.
So, in conclusion, some people are pragmatically justified in choosing Christianity, given finite human nature. Others are not justified but can still have some virtue in doing so. Still others are completely flaunting their responsibilities. The arguments themselves, however, fail; one has the practical need to choose Christianity only because of one's own individual situation which is never commensurate with the answer given, nor is the particular solution of Christianity commensurate with the general problem of humanity which can be recognized by non-believers before making the decision.
Addendum: But now, some second thoughts. I find myself in the place where I find that, (a) to dive into Christianity would be to ignore my reasoned judgment, and so to give up seeking truth; (b) to stay where I am will only exacerbate the bitterness, irritation, and self-centredness which attend my criticisms and daily life under the stress of seeking while still in the church, and so I would be giving up seeking goodness; and so (c) to leave Christianity would be the only way to seek both truth and goodness. This would seem to be a pragmatic argument for leaving Christianity; does it fall prey to the above criticisms? Does a negative solution in a pragmatic argument yield the same problems as a positive? Does the inclusion of theoretically rational considerations change matters? How about a universal solution, such as religious pluralism, or some sort of transcendental condition for hope?