I've posted here before about why I think that historical arguments for Christianity don't work, due to an empirical deficiency in research: they don't answer competing claims from other religions (the example I gave was the reincarnation of the Dalai Lama), which (a) demonstrate enough to show that they should be taken seriously, and (b) would, if true, immediately prove (orthodox) Christianity wrong, no matter what the state of our own arguments. However, I am wondering whether even this is giving too much credit to the historical arguments; maybe they can't even in principle do this much?
Where do we get our knowledge of classical, orthodox Christian doctrine? From Paul, from Peter, from John, (from Priscilla?), from the church throughout the years, and so on. Now, even if Jesus was crucified, died, and was buried, and on the third day rose again as the Son of God (i.e. fully God and fully man) in power, it could still stand to reason that almost everything else that these later thinkers wrote is dead wrong. Maybe a good try, but wrong. Jesus' resurrection and the accurate transmission of the NT and OT texts has nothing to do with their theological validity.
At this point, one could say that God wouldn't leave His people hanging, and would give them direction through his inspired Word. Well, 2000 years later, I'm still looking for that direction; the church has quibbled, and no one really agrees on these issues of utmost importance. We look to our readings of Scripture, but so does the other side. We change our minds, and read back our thoughts to past transmitters of the tradition. Where is the guidance? There isn't enough to establish the argument that the NT is valid theologically, at any rate.
Ok, fine, granted, but what about Jesus? He said some stuff too, and maybe that at least shows that what later thinkers said was good, when it was strictly concerned with unpacking what He said. If He truly were God Incarnate, He would have been right too, and so an historical argument which gives evidence that He was who He said He was (and which further gives evidence that He said that He was God; not exactly a finished task!), gives evidence for some NT theology. But first, why think that we understand Jesus when no one around him seemed to do so? To be honest, even the speeches at the Last Supper where the disciples thought that Jesus spoke plainly are pretty opaque to me if I don't start by assuming that one tradition or another is true, so why should I think that I understand His parables?
Second, if Jesus was truly human (which would be necessary for any sort of orthodox Christianity), then how did He have perfect knowledge? If He truly were tempted in every way as we have been, then He had to wrestle with epistemological problems which cause so much grief for those concerned with knowing the truth rather than merely with having a spot of worldly comfort. So, how could He have known all the theological truths?
The answer could be that it would be like the way in which He did not sin: Jesus as human was tempted to sin and had to struggle for correct knowledge, but Jesus as God together as the entire Trinity saw to it that Jesus the unified person would come through in both practice and theory. But, are these two equivalent? It seems that it would be possible for someone not to sin, even within social settings according to a normal life, even if extremely difficult. But how can one, growing up in an environment with wrong thinking (as every environment is) without any source to correct that, to suddenly reach the Truth through human means? If there were no demons which possessed people, how would the human Jesus have come to know that? If a miracle, then Jesus didn't face our struggles; if not a miracle, then it is highly implausible that Jesus' judgments were all correct. But if this is the case, then why take Jesus' thoughts on theology as more than a highly inspired individual?
Maybe this shouldn't be a problem for theology; God could still have performed a miracle. It is logically possible. But for an apologetic argument, creating a key bridge from an historical resurrection to orthodox (or even mostly orthodox) Christianity by resorting to an actual miracle (not merely the possibility of miracles, but a really instantiated one) which nonetheless has absolutely no historical backing, seems to me to defeat the purpose. There may even need to be two miracles: one, that Jesus got it right, and two, that we have understood him properly in all the details we hold dear.
So, if this (together with former posts) is right, then there is no argument (even a strictly evidential one) outside of Christianity which could provide grounds for accepting it, and I therefore have no reason to prefer it to Islam or Buddhism, or just a straight-up rational religion or a pure pluralism. Further, anyone who thinks they do, either started by assuming Christianity or took a blind leap of faith. One can still choose to be a Christian, but it is nothing more than a gamble with bad odds, unless perhaps pluralism is true.