There are many good reasons why living organisms are adept at moving themselves around without tripping or falling all the time. This was such a crucial skill for survival that early on in our evolutionary history, the primitive brains of our ancestors were primarily concerned with coordinating muscles and senses. Any creature that fell over too much was eaten by predators pretty quickly, creating a strong evolutionary pressure toward animals that could move reliably. Only the creatures able to sense the location of their limbs in relation to the ground, would survive long enough to reproduce. So generation after generation of better-moving animals resulted in animal brains that could instinctively move over rough ground. We still have this primitive brain buried deep inside our own. In the missions of years of evolution since then, we’ve added layers of new brain material around this brain stem. Bit we have an instinctive ability to stand on our limbs, walk, and cope with rough ground that is given to us by the unconscious reptilian brain inside us. Without it, we would be much like one of our robots – stumbling, clumsy and prone to losing our balance (Why Sh*t Happens: The Science of a Really Bad Day, 2009).
