Alvin Plantinga, answered from the texts and cited to the page.
Christian belief remains warranted in the face of sincere awareness of religious diversity if the warranting conditions are met: a properly functioning sensus divinitatis combined with the Internal Instigation of the Holy Spirit.123 Four critic moves and four replies. Historical conditionedness does not entail unwarrantedness — that Einstein wouldn't have believed special relativity in the eighteenth century says nothing about whether relativity is warranted now. Moral perniciousness creates a dilemma for everyone — every doxastic attitude is 'arrogant' on the critic's standard, since believing p always involves believing those who hold not-p are wrong; arrogance attaches to persons, not to beliefs. Diversity and probability is a category mistake — Christian belief is not a hypothesis being assessed for probability against alternatives; properly basic beliefs are not evaluated that way. Diversity and warrant rests on the alethic / epistemic asymmetry — the Christian believes she has access to truth the dissenter lacks (the sensus divinitatis and the Internal Instigation of the Holy Spirit), and that is the epistemic difference that makes warrant possible even given internally available parity.45
But — and this is the late-WCB concession — warrant CAN decrease in some real cases of sustained sincere contact with sincere adherents of other religions.
In the next chaptei, we turn to the question how specifically Christian belief, not just geneiically theistic belief, can have warrant; in answering that ques¬ tion we will also see how the5cn.sw5 divinitatis is repaired. The Extended Aquinas/Calvin Model: Revealed to Our Minds The Spirit himself testifies with our spirit that we are God's children.Warranted Christian Belief, pp. 241–242
Still, in recent years probably more Western Christians have become aware of the world's religious diversity; we have probably learned more about people of other religious persuasions, and we have come to see more clearly that they display what looks like real piety, devoutness, and spirituality.Warranted Christian Belief, p. 440
For at least some Christian believers, an awareness of the enormous variety of human religious responses does seem to reduce the level of confidence in their own Christian belief. It doesn't or needn't do so by way of an argument.Knowledge and Christian Belief, pp. 113–114
Again, I don't think so. I believe in serious actualism, the view that no objects have properties in worlds in which they do not exist, not even nonexistence. Others do not be¬ lieve this; I am unable to convince them; and perhaps the internal markers of their dissenting views have for them the same qualities as mine have for me. Am I being arbitrary in continuing to think as I do? I can't see how.Warranted Christian Belief, pp. 453–454
Furthermore, their beliefs might seem the same to them from the inside, so to speak, as my beliefs seem to me. Am I then being arbitrary, treating similar cases differently in continuing to hold, as I do, that in fact that kind of behavior is dreadfully wrong? I don't think so.Knowledge and Christian Belief, pp. 111–112
Plantinga's pluralism reply has been the standing target of critics who think Reformed-epistemological exclusivism is arrogant, epistemologically irresponsible, or culturally insensitive. The four-pronged defense has held its ground argumentatively; Hick, Gutting, and Schellenberg have not, on most readings, dislodged it. Kelly Clark's 'Pluralism and Proper Function' in the Baker volume develops, sympathetically, what Clark argues Plantinga himself concedes only briefly: that the warrant of Christian belief can decrease in real-world cases of sustained sincere encounter with sincere religious others. Clark's 'Jennifer' case is the canonical example. I make the concession in the final paragraphs of the WCB pluralism chapter; Clark argues, fairly, that the concession deserves more weight than I give it.