In reading about Christianity, certain historical debates (for example, debates about whether Jesus of Nazareth had siblings) remind me of various theological debates. In many of the latter cases, I am left thinking “Who knows?” Especially when dealing with obtuse subjects such as theology, human reasoning can easily go wrong. Unless we can figure out a way to rigorously check by tests or technologies some theory, it’s generally not something to trust (whether in philosophy, theology, science, or, say, cooking). Indeed, many advances in science, say, come from someone figuring out how to test something or other in a new or better way.
With historical debates, the evidential base is too weak to decisively settle all sorts of questions in Christianity, many of which are therefore debated at length. There is no way for us to actually know the answers to many relevant historical questions in Christianity with current techniques, in a robustly warranted way. Debate, then, is about figuring out what is the most plausible scenario, even though the subjective probability we get in the end for the most plausible scenario might be very low – even lower than 50%. (Furthermore, when you are considering multiple debates, the probability that you have all or most of them right drops quickly. For example, the chance that you’re right about two different hypotheses under consideration for two different debates, where for each hypothesis you have given it a 60% chance of being true, would be then 0.6 * 0.6 = 36% chance of being right for both.)
What to do?
It seems that, when building a form of Christianity, it makes sense to place things that are evidentially robust at the base. This means de-emphasizing certain historical or theological claims, and instead emphasizing practical claims, where the results are here, and now, and robust. For example, compare certain aspects of the historical Jesus with the concept of the ‘living Christ’.