Anderson borrows his position on epistemic warrant from Alvin Plantinga. On their view, warrant is "that epistemic quality enough of which transforms mere true belief into knowledge." This is to be distinguished from mere justification, which is widely thought to be insufficient for warrant. Now, even though Anderson, again following Plantinga, assures us that theism is indeed justified, this justification he only understands in the weak deontological sense expounded by Plantinga in Warranted Christian Belief. For example, Plantinga tells us that a justified belief may be primarily if not entirely founded on ineffable impressions and sensations, and may even sometimes amount to mere "wishful thinking." For Plantinga, we do not require good reasons in order to satisfy the epistemic responsibility sufficient to deontologically justify our beliefs. To quote him directly:
How could [a Christian] possibly be blameworthy or irresponsible, if she thinks about the matter as hard as she can, in the most responsible way she can, and she still comes to these conclusions? Indeed, no matter what conclusions she arrived at, wouldn't she be justified if she arrived at them in this way? Even if they are wholly unreasonable, in some clear sense?
For my own part, I would like to insist that we demand much more of justification, and indeed of epistemic responsibility itself, than what Plantinga allows in his illustration. I want to find people accountable for willfully holding unreasonable beliefs. If a Christian theist has no good reasons for her Christian theism, and recognizes that deficiency, then she is epistemically duty-bound on my view to renounce it. Anderson, however, shares Plantinga's position, not mine; yet while he is correct that Christian theism is justified on Plantinga's account of justification, that won't be particularly helpful if wish to hold our beliefs to a higher standard.
Beyond giving good reasons or providing justification, however, Anderson strives to show that, if Christian theism is true, then it is also warranted. To this end, he again turns to Plantinga, whose account holds, in his own words, that a belief is warranted only if
(1) it has been produced in me by cognitive faculties that are working properly (functioning as they ought to, subject to no cognitive dysfunction) in a cognitive environment that is appropriate for my kinds of cognitive faculties, (2) the segment of the design plan governing the production of that belief is aimed at the production of true beliefs, and (3) there is a high statistical probability that a belief produced under those conditions will be true.
To endow Christian theism with warrant, Anderson turns to a doctrine he attributes to Thomas Aquinas and John Calvin, in which God brings forth in his human creatures a sensus divinitatis, that is, an innate, authentic sense of the divine. According to this view, the Christian God has built into our cognitive faculties a strong tendency towards theistic belief, indeed towards Christian belief. So, even though we might not have good reasons to believe in God, our innate proclivities urge us to accept Christian theism nonetheless, as intended by God's design. This, Anderson assures us, satisfies Plantinga's account of warrant, and thus, if God exists and the Aquinas-Calvin doctrine is true, then believers have warrant, and therefore knowledge, of God's existence.
For Anderson, an important corollary of Plantinga's analysis is that the question of warrant for theism is tied up with the question of its truth, and that we cannot rightly consider either issue independently of the other. For the most part, I agree with this conclusion: If God exists and has endowed us with a sensus divinitatis or something analogous, then it seems fair to say that theism is warranted on Plantinga's account; conversely, if God does not exist, then we do not seem to have any access to epistemic warrant for theism. In other words, as long as we limit ourselves to Plantinga's definitions, I don't disagree with Anderson's thesis that "if the basic contours of the Christian narrative are true, then there is good reason to suppose that the Christian's beliefs are warranted." Rather, I would like to point out that we still lack good reasons for Christian belief itself. Put another way, I'm interested in higher epistemic standards than those which Anderson borrows from Plantinga. Even if Anderson's vision of Christian theism is true, and God has designed our cognitive faculties to gravitate inexorably towards theistic belief regardless of reason or evidence, I would still be unwilling to call his belief knowledge; I demand more than just a divinely-programmed belief tendency to constitute warrant.
In my judgment, the most important observation we can take from Anderson's treatment is that he declines to offer any good reasons to think that theistic belief is true. This omission seems deliberate, and so I don't mean to suggest he tried and failed. However, I nevertheless find it extremely interesting that, in his discussion of warrant for Christian theism, he avoids any hint that we might be able to find rational justification of the strongest sort we typically desire. Furthermore, Anderson remains unable to conclude from his outline that theism really is warranted; the most he can say is that, if Christian theism and the Aquinas-Calvin doctrine both happen to be true, then belief in God satisfies Plantinga's weak account of warrant. In the mean time, if we seek to epistemically justify God-belief according to stricter standards, as I think any theist should, then we must look elsewhere to achieve that goal.
 Anderson, James. Paradox In Christian Theology: An Analysis of Its Presence, Character, and Epistemic Status (2007), p158.
 Plantinga, Alvin. Warranted Christian Belief (2000), pp100-1. http://books.google.com/books?id=BypSHmoozV0C
 Plantinga, p101.
 Plantinga, Alvin. Warrant and Proper Function (1993), pp46-7. http://books.google.com/books?id=4OqJbrwcHtoC
 Anderson, p209.