“The American system of jurisprudence recognizes a wide range of factors, predispositions, prejudices, and experiences that might cloud our judgment, or affect our objectivity—sometimes even without our knowing it. It goes to great, perhaps even extravagant, lengths to safeguard the process of judgment in a criminal trial from the human weaknesses of those who must decide on innocence or guilt. Even then, of course, the process sometimes fails. Why would we settle for anything less when interrogating the natural world, or when attempting to decide on vital matters of politics, economics, religion, and ethics?”