It seems to me that Christianity passes the Outsider Test For Faith (OTF), where a person steps 'outside' their worldview and examines it rationally from that position, with ‘flying colours’!
Quote from John W. Loftus (proponent of the OTF):
“That Christians object to taking the Outsider Test for Faith only confirms it doesn't look good for their faith. For if Christianity passed the OTF with flying colors Christians would be arguing on behalf of it and pressing that case at every step along the way.”
To answer this generalisation: a) I do not object to taking it, b) I don't think that it looks bad on the Christian worldview, c) It passes with 'flying colours' and d) It's a shame that more people haven't used this for some people who have become atheists for less-than-rational reasons, and that more people haven't defended the Christian worldview along the lines of the OTF.
As for myself, I am a Christian (specifically, to counter stereotypes, Christian evolutionist, Christian feminist and believer in universal reconciliation), and I do not believe that this "Outsider Test For Faith" poses any real challenge, or even necessarily conveys a bad image, to the Christian worldview if properly considered. I would like to have some atheists properly examining their worldviews, based on informed evidence, by this method!
By the Christian "worldview" (in contrast to the atheist "worldview") I mean the outlook on reality that we have, our fundamental presuppositions and commitments to ideas; all people have their own 'worldview'. By 'Christian', in this case for clarity, I refer to worldviews possessing the following characteristics (these are the basics - a Christian may have many ideas built on these - but these, in my opinion, are the foundations for categorising a worldview as 'Christian'):
1. God, as the intelligent Mind behind the universe, exists
2. God brought about the creation of the universe
3. God is benevolent, and chooses to be involved in human matters
4. Jesus is the Son of God, and God having chosen to take on human form
5. Jesus is the Christ (anointed from God)
6. Jesus was raised from death to life by God after crucifixion
7. God is able to sustain for other beings life subsequent to physical death
To show this, I, as a Christian, can adopt a hypothetical agnosticism, where I imagine that in fact I start out not knowing if these facts are true. Agnosticism is chosen because it is 'outside' both the atheistic worldviews and the theistic worldviews. Then, a case for the above 7 points can be built from the bottom up, without any reference to the inspiration of Scripture (which I haven't included as an absolute foundation; it seems to me that a person can still be a Christian if they don't concede the inspiration of the Bible, although I disagree with this approach) or prior Christian assumptions. Below is a very quick outline of what forms of arguments can be used for each point:
1) Evolutionary argument against naturalism (showing that rational discourse fits better into a theistic worldview),
Design of the fundamental principles of physics (e.g. the very presence at all of the very specific strong force, or gravity, as well as fine-tuning and the mathematical nature of physical equations, especially if there is a multiverse and thus even more complexity),
Cosmological argument from contingency (i.e. non-necessity of any of the contents of the universe, which points to a metaphysically necessary Mind on whom they are contingent on, especially given Godel's theorem),
Transcendental argument (where the logical basis of the universe (and the universal nature of the very laws of logic), independent of human minds and the existence of matter, points to the providence of a transcendent Mind)
(amongst other examples)
2) The points in (1) contribute to this, together with evidence of the Big Bang, and evolution, that show some degree of development that can take the form of God's action.
3) The historical evidence for the Resurrection of Jesus (also supporting (1) and (2), and is made more plausible by the arguments in (1)) points to an affirmation of Jesus' teachings, centred on love: this is the strongest argument for this aspect of God's nature.
The moral argument that bases objective moral principles in the metaphysical necessity of God (not arbitrary, because they are based in God's loving nature), supports the idea of God's benevolence, since such principles far, far, surpass egoism, and they did not have to develop at all (i.e. the evolutionary origins of such moral principles to which I concede, through the intervention of God, did not HAVE to occur).
The ‘Problem of evil’ is an overall weak argument; firstly, it only argues against God’s goodness, and can say nothing about His existence. Secondly, it fails at this because it presumes a moral standard, and thus assumes that we understand the moral standard, which would require the assumption of God’s goodness to start with. Thirdly, even not taking this second point, given universal reconciliation (which seems to be the teaching of St Paul), treating humans as ends in themselves, God could easily have good reasons for allowing evil, as a consequence of free will, in order to bring about eternal happiness for every single person.
The human potential to have religious experience, which did not have to be the case, brings about largely positive and sometimes very dramatic results and points to God’s benevolence.
The human potential to have very vivid and largely positive NDEs (which, by the fact that this faculty exists at all to produce such experiences, suspiciously seems to correspond with a potential for life after death, and its positive nature supports God’s benevolance)
4), 5) and 6) can be established by the excellent case for Jesus' resurrection (made more plausible by the arguments in (1), and which should not be excluded without reason as a possibility, especially given reports of miraculous activity (and the vivid nature of NDEs) in recent years), from the minimal facts, changes in teaching from Judaism, many disciples' transformation based on something which they would have explicitly know to be false, and a suspicious lack of convincing historical evidence against the resurrection, as well as a multitude of other evidence.
This can be linked with historical evidence for the activity of the early Church, and by treating biblical documents as at least partially reliable historical documents to support (4) and (5).
7) is supported by (6) and the human potential for NDE, as well as just being a logical consequence of (3) combined with God’s power.
Let me say here that this CERTAINLY is not an all-inclusive list, but these points here give an example on how Christianity can certainly pass the OTF from a 'bottom up' perspective from agnosticism. Many will have heard lots of these arguments before, but properly thought-out and articulated versions of them not afflicted by 'straw man' assumptions are actually very powerful, and certainly enough for a Christian to pass the OTF. In light of this, the OTF could even be used to support Christianity.
To the contrary, it seems to me that, in stark contrast to the, in my view, pass 'with flying colours' of the Christian worldview, the atheist (stepping into the agnosticism viewpoint), has few comparably good arguments that a) don't make silent theistic assumptions, b) don't set up a 'straw man' form of Christianity and c) doesn't just act as an 'atheism of the gaps', feeding on where particular theologians may not have explained things fully enough.