One of the most interesting challenges to reasonable and rational Christianity was to reject the possibility that Christianity could or more strongly, should be defended rationally. Such a rejection might immediately seem implausible for those of us schooled in even the mildest of the rationalist traditions. However, the rejection is sometimes not a rejection of rationalism per se but the claim that the logic is internal to the form of life and cannot be expressed outside it. Thus, we might conceive of this particular view as Wittgensteinian fideism. Yet, even more radically, there are some that held that something about faith is opposed to the limitations of rationality, the mildest form being in the perhaps captured in many charismatic evangelical churches that “reason takes us this far, faith takes us further (or to the ‘next level’)”. However, there is also the extreme form of that view that reason is implacably opposed to faith as found in the work of Kierkegaard who reacted to what he saw as the idolatry of Hegel with regards to the totalising system of rational dialecticism. Kierkegaard (and I would also note Heidegger  ) are perhaps the most sophisticated expressions of this subjective position.
We should make a leap of faith with regards to our practical reason and are rather seeking after an authenticity of the purity of heart, the precious gift of a good conscience borne out of a living faith:
“She recounts that she had heard someone say that, on being brought to the hospital, Kierkegaard had said he had come there to die. Yet on seeing him she saw radiating from his face, ‘mixed with the pain and sorrow’, a ‘blissful feeling of triumph’: ‘Never before have I seen the spirit break through the earthly sheath in such a way and convey to it a lustre as though it were itself the body transfigured in the luminous dawn of the resurrection’”.
Under such a conception, it is only in reaching beyond the limitations of our ability to express in language that we truly know:
“The most embracing general message of Fear and Trembling seems to be, then, that the notion of faith is in current discussion of it so far cheapened that what is talked about is not properly called faith at all; and that if we are to praise venerable figures like Abraham, or Abraham in particular since he is revered as the father of faith, we should be made to appreciate what it was like to be Abraham undergoing the trial of faith. If Abraham is to be said to be great, then we should be given a clear picture of what it was that he achieved…” (emphasis added)
Kierkegaard communicates something of great importance to us here about the limits of reason or the proper conception of reason, but it is his Christian foundation that tempers the leap into unrestrained irrationality. Sartre used his starting point but in losing his “faith” lost himself:
“My retrospective illusions are in pieces. Martyrdom, salvation, immortality: all are crumbling; the building is falling in ruins. I have caught the Holy Ghost in the cellars and flung him out of them. Atheism is a cruel, long-term business…I have renounced my vocation, but I have not unfrocked myself”.
So, we seemed to have proved the point we started with, at some point, our worldview can only be understood in the terms of the system itself and in how we have lived as cultures. Baier refers to the “wisdom of previous ages” and Blackburn appeals similarly:
“Perhaps we never found logos or a ‘first philosophy’, an underlying foundational story telling us, from somewhere outside our own world view, just why that world view is the right one. But perhaps we have learned to do without that, just as we learn to retain our hard-won confidences, without closing our minds to any further illuminations that the future may bring. Above all, I hope we have become confident in using our well-tried and tested vocabulary of explanation and assessment. We can take the postmodernist inverted commas off things that ought to matter to us: truth, reason, objectivity and confidence. They are no less, if no more, than the virtues that we should all cherish as we try to understand the bewildering world about us.” (emphasis added)
Blackburn recognises that a worldview will define our ethical life and indeed our theoretical life also. Unlike Sartre he refuses to surrender to the absurdity of his existence but chooses to believe that what we consider ethically valuable really does have value despite the inability to give an exhaustive justification that would satisfy the global sceptic. We are not too far from Kierkegaard again for though we cannot completely excoriate the sceptic, they are unimportant and/or irrelevant to practical reasoning and we choose the ethical life; it is the essence of legitimate and responsible human life.
 D Z Phillips and Kai Nielsen had an exchange over many years on this issue, see Nielsen, K., & Phillips, D. (2005), Wittgensteinian Fideism?.
 However, such schools cannot but help to come to relativistic conclusions as they can offer no criteria to judge between competing truth claims; indeed, it becomes illogical to assert there could be an objective truth. As we have noted, the postmodern malaise currently afflicting the academy and popular culture asserts that the rigorous intellectual defence of any position might be considered imperialistic or authoritarian. The sceptic may then assert with the nascent free-thinker Bodin (1593) that “each is refuted by all” for their worldviews are incommensurate. Plantinga elegantly refutes Bodin and the many other pluralists or secularists that assert a similar position by exposing the fallacy lurking there that incommensurability necessarily implies some kind of incoherence. Plantinga argues that one can have sufficient warrant to maintain an exclusivist epistemic position though you are very much aware of the “facts of pluralism”, particularly when the initial “defeaters of pluralism” end up reinforcing your exclusivist convictions as we noted in the main body of the thesis.
 Although known for the utter density and opaqueness of his work, Heidegger was also able to write with astonishing vividness, his “The Bridge” (Heidegger, 1985 (1971), pp.150ff) is a masterpiece of mindfulness and encounter with the world.
 Kierkegaard, S. (1996). Postscript – The End or the Beginning. In S. Kierkegaard, & A. Hannay (Ed.), Papers and Journals. London: Penguin Random House., p.649.
 Hannay, A. (2003 (1985)). Introduction. In S. Kierkegaard, Fear and Trembling (A. Hannay, Trans., Kindle ed., pp. 48-552). London: Penguin.
 Sartre, J. P. (2000 (1967)). Words. London: Penguin., p157.
 Blackburn, S. (2006). Truth – A Guide for the Perplexed (Kindle ed.). London: Penguin., p.220.