As [18th century Scottish philosopher Thomas] Reid pointed out, to know anything about the world we must accept what our senses tell us. We can “dare to know” only if we trust the “testimony of our senses” (as [David] Hume called it.) Similarly for reason, memory, and our other cognitive faculties. We simply have to take our faculties at their word.

And by taking reason and sense perception at their word, we trust their testimony. Testimony, therefore, is foundational to everything we believe. Without trusting our cognitive faculties, we could never believe anything.

Moreover, remember, believing something on the basis of testimony is faith. Therefore, faith is the starting point for all we know and believe. Anselm of Canterbury had a much more reasonable motto than the Enlightenment’s, one that hints at the importance of faith: “Credo ut intelligam,” that is, “I believe that I may understand.” Reid put it a bit differently, saying that the unjust must live by faith no less than the just.

So, when [Victor] Stenger complains that science and reason don’t rely on faith, he’s missed the Enlightenment’s important (and unintended) lesson about faith, reason, and evidence. “The theist argument that science and reason are also based on faith is specious,” he says. “Faith is belief in the absence of supportive evidence. Science is belief in the presence of supportive evidence. And reason is just the procedure by which humans ensure that their conclusions are consistent with the theory that produced them and with the data that test these conclusions.” Stenger is right about one thing: having faith is believing something without having an argument for it (“belief in the absence of supportive evidence”). But Stenger’s failure to realize that science, too, is based on faith (because everything we believe is, ultimately) is a massive mistake. Yet it’s as common as it is colossal. – Mitch Stokes, A Shot of Faith to the Head: Be a Confident Believer in an Age of Cranky Atheists