The Pope’s recent quotations both from Byzantine emperor Manuel II and verses from the Koran were intended as commentary on the history of rationalism, and his audience understood this not as an insult to Islam but rather as criticism of prevailing Western views about liberty and reason. The reaction, however, from nearly every quarter outside his immediate audience was that he offended the religion of Islam.
I wonder if the Reformed tradition’s own Karl Barth might bring forth a helpful comment, but perhaps in a way that Barth may never have dreamed. Can you recall Barth’s fiery “Nein! ” to the existence of natural theology? Barth had been greatly affected by the per vasive liberal theology of his day, which preceded the developments in W WII Nazi Germany. Examining the roots of liberal theology, Barth narrowed his sights toward a sharp critique of the Western Roman Catholic reliance on analogia entis or “analogies of being,” a foundational doctrine outlined centuries earlier by Thomas Aquinas.
The 13th century Aquinas had believed, as did most ever yone of his day, that reason could lead to an understanding or awareness of God Himself. Outlining arguments of those who preceded him, some of them ancient Greek philosophers, Aquinas gave his “five ways” for the existence of God. One example was the argument from St. Anselm, “God is that than which nothing greater can be conceived.” Aquinas believed that reason, when sincerely applied, could lead to the real, the true, the good, and the beautiful. Since God is the author of all truth and all that is good, reason leads to a confrontation with God.
Karl Barth is among several interesting figures of the 20th century to challenge such a view. Barth credited the 18th century philosopher Immanuel Kant, who was himself a German Lutheran, for reminding the world that a knowledge of God is not found through reason alone. In his Critique of Pure Reason, Kant examined all the arguments for the existence of God, showing soundly that the existence of God could neither be proved nor disproved by “pure” reason. Kant produced equally strong arguments for and against the existence of God. For example, the argument just mentioned from St. Anselm might make God a “big stinker” since the term “nothing greater” is never clarified.
Barth hailed Kant as extremely helpful for theology because he “made room” for faith as a faculty of understanding. Taking this important cue from Kant, Barth went beyond his criticism of the liberal theology of his own time towards a rather stunning critique of a key theological linchpin found throughout the Roman Catholic tradition. Barth questioned any and all reasoning about the nature of God that was not first grounded “in faith.” Barth consequently resurrected key elements within Protestant “Reformed” theology. Rather than analogies from being (analogia entis), we know God through analogies from faith (analogia fide). Hence, Barth’s view became a Neo-Orthodoxy because he revived key touchstones (sola fide) of the Reformed faith regarding the knowledge of God.
Barth could be kept in mind in relation to the current fury over the Pope’s indirect comments on Islam. From the start, when approaching inter-religious dialogue, mere respect leads us to think of a “reason” that is not bound by Aquinas’ stress on natural revelation and reason. The pluralism and skepticism of our own time is very different than the time of Thomas Aquinas. We need a kind of reasoning that is sufficiently respectful for all parties found in our own day and time.
First, reason itself is not so easy to define. For example, the reasoning of a sincere person of faith would be different than that of an atheist, at least with the subject of theology. Reason has levels, paradigms, and irrationalities that frame its direction. Remember Pascal’s comment in Pensées, “the heart has its reasons the mind will never know.” There is in fact something imperialistic or pretentious by saying to an atheist that his own reasoning is bringing him closer to God. That would be rather insulting, or at least circular or tautological. The atheist doesn’t believe, won’t believe, so his reasoning is not something that leads to God, or at least he will not let it do so.
What if, like Barth, Christians took “faith” as the common ground, not reason, in the approach to Islam and to other religions and philosophies? What if a Christian theology of religion, of other religions outside the Christian tradition, was approached not through natural revelation and reason, but within the epistemology of faith? This might be particularly helpful in the approach to people whose faith extends from the faith of Abraham. In other words, faith, that great treasure of the Church, does not merely belong to Christians. Faith (the faith of Abraham) is also approached by several other religious expressions. In one key sense, Jesus, the Jew, did everything he did in order to bring the world to this faith, a faith shared by the traditions of Judaism and Islam.
Mohammed also lived and died for “this faith” to be spread throughout the world. Rather than making “reason” the common ground for a dialogue about God, 
What if, like Barth, Christians too “faith” as the common ground, not reason, in the approach to Islam and to other religions and philosophies? 
Christians could speak from inside the point of view of faith found among various traditions of Christians, Jews, and Muslims. A “reason” that claims to spiral us towards natural revelations of God may in fact be insulting within a world of pluralism, atheism, and colonialism. For Karl Barth, such a dialogue would never lead to a grasp of God any way, due to the limits of knowledge itself.
To establish a sincere dialogue about God–about who God is, what God said, what God wants–it may be better to maintain the stress on faith, found within the Reformed tradition/s. Christians could maintain the Protestant principle “by faith,” but with the caveat that Christians do not own or have a monopoly on this faith. This is because the faith of Abraham preceded Christianity by nearly two thousand years. In this sense, traditions which spring from Judaism, Islam, and Christianity have something to teach and say to each other.
In short, the Roman Catholic view expressed by Pope Benedict–that reason can lead to a knowledge of God–muddles the much-needed dialogue with Islam because it misdirects us to a trust in reason. As Karl Barth pointed out, sin and the limits of human epistemology make this an untenable approach to God, who revealed Himself specifically in the history of salvation. A lthough not an application found in Barth’s christocentric systematic theology, the stress on faith within the Reformed tradition may better help Christians to make contact with the faith of the Muslim religion.
