Why is the world orderly, and how does this order come to be? Human beings inhabit a multitude of apparently ordered systems-natural, social, political, economic, cognitive, and others-whose origins and purposes are often obscure. In the eighteenth century, older certainties about such orders, rooted in either divine providence or the mechanical operations of nature, began to fall away. In their place arose a new appreciation for the complexity of things, a new recognition of the world's disorde