Mystery Odor and Bloomberg's Confidence

CNN is reporting a mysterious odor in New York City. I had to chuckle at Mayor Bloomberg's "confidence." He has no idea what is causing the smell, but is very confident that it is not dangerous:

"One thing we are very confident of, it's not dangerous," Bloomberg said. "How long and what the sources are, we just don't know."

This reminds me a little of the confidence of some scientists that macroevolutionary theory explains the Cambrian Explosion, even though scientists are not sure of the actual mechanisms and/or environmental factors that caused it.