Agustine summarized in just a few words why faith is essential to human society by saying, “Nothing would remain stable in human society if we determined to believe only what can be held with absolute certainty.”
I have certainly come across people who look down on religious people as being weak minded because they allow faith to play a central role in their lives. I have never let this bother me because I have always felt that faith and reason do not have to be opposed. However, St. Augustine is certainly capable of putting this into more eloquent terms than I am able to.
He wrote against the Manichees idea that “they would put aside all awesome authority, and would by pure and simple reason bring to God those who were willing to listen to them.” Although they spoke all high-and-mighty he pointed out that they “fell silent when faced with hard questions”. But why?
One of the benefits of faith is that acts as a springboard for reason. Augustine explains that trusting an authority, or having faith in them, is what enables learning — in all parts of life. It is as unreasonable to expect to come to understand God through only reasoning as it is to expect us to only allow into our history textbooks what can be verified by mathematical reasoning. Rather belief, or faith, is a “constituent part of historical knowledge” which means that any knowledge of the past must depend upon someone’s word — someone’s authority.
When unified, authority and reason are what leads a soul to God. Each one informs the other, as we reason who we should believe and who’s word we must rely on. As Wilken points out, it is reasonable to begin in faith by following, but that doesn’t make faithful people weak minded “sheep”. Faith is unavoidable, because reason cannot fill specific gaps, and so faith must intercede.
Introduction to Theology: Charlotte Spraul 