Years ago my friend Paul, a manager at a waste treatment plant, held up two glass laboratory beakers at a speaking engagement. The one in his right hand contained a clear liquid, the one in his left a thick, black liquid.
“This,” he said, jiggling his right hand, “is lab-certified 100 percent pure water.” Then he jiggled his left hand. “And this, well, this is the raw product I deal with all day long. Here’s the question: How much of this could I put in the water, and you still drink it?”
