The Evolution of Human Reason

Descartes' Meditations on First Philosophy was a groundbreaking work, beginning with a dispensation of all knowledge attained to that point in his life, and beginning anew, attempting to find through human reason certain basic truths about the world. What I found most interesting about his method is the idea of accessibility. No longer was one forced to subscribe to a system of beliefs in which the chief players held superior knowledge of the worldview, keeping it within their inner circle. What was once necessary to take on blind faith was now empowered to all with even a basic mental capacity. More importantly, all those with a basic capacity for reasoning can see that Descartes' theories find a common point of concurrence for mankind to agree upon. The previous paradigm does not account for this, creating points of contention. Thus, those of a different sect of faith (e.g. Catholic vs. Protestant vs. Atheist vs. Muslim vs. Buddhist, etc.) could never agree on certain tenets of their faith that do not apply to the others.
One can see this shift of balance to the human reasoning in most aspects of modern human life, especially in the establishment of the "scientific method" as a means to "truth". Charles Darwin's observations aboard the HMS Beagle and at the Galapagos islands point to a need to explain through natural means, rather than automatically assigning the transmutation species to God's will. He demonstrates a Cartesian preference for order, neatly assorting various bird species according to their similar physical characteristics, then uses deductive reasoning to conclude that, over time, certain finches had developed longer, narrower beaks as food became scarcer, allowing the finch to dig for insects in holes in fallen trees and so forth. One must take notice of the similarities to Darwin's categorical assignments and those of the professor and her mud and tree maps in the African forests and grasslands.
Are we to discard Descartes ideas, then, just because we get stuck in a specific mindset? Not necessarily. Although it may cause us to be unable to truly think "outside the box", it also gives man/womankind a base of commonality, from which we can begin a useful dialogue that can be understood on a specific set of terms that do not need to be indoctrinated or taught to us; we are born with our human skills of reason.