A Balancing Act

I remember playing a game as a child in which we would bend one knee and grab our foot behind us and then try to race—limping, stumbling and falling over as we struggled across the grass toward a finish line. That’s what happens when we have only one leg to stand on, or assume that somehow two left feet suffice for one of each.

This balancing act is repeated throughout most of nature. Two eyes to give perspective. Two arms and two hands to provide dexterity. Two sides of our brain that tandem. All these things come in pairs because there are many things in the physical world that work…