In the book How to Make a Mind, Ray Kurzweil proposes the intriguing idea that the brain behaves like a massive pattern recognizing machine. The beauty of the concept is that the brain–or the neocortex to be more exact–is entirely focused on this single task and all activities within the brain can be explained as examples of pattern recognition.
When we see a friend, we first see curves and shapes, then we identify a face and finally we recognize the significance of this face. This hierarchy is, from beginning to end, a pattern recognition exercise (shapes turn into a face, and a face turns into a friend). Ideas, behaviors, responses, etc, all can be understood as the brain finding these patterns and matching them with similar patterns stored in the brain in the form of memories.
I love the idea that the amazing complexities of the brain are ruled by one “simple” algorithm.