Gary Gensler, chairman of the Commodity Futures Trading Commission, likes to go to the past -- sometimes as far back as 1,000 years -- to explain the financial situations of today.

REGULATION-SUMMIT/For example, derivatives existed for 145 years, since the Civil War, and they became regulated in the 1930s, he said at a Reuters Global Financial Regulation Summit in explaining that derivatives need regulation.

If you only want to go back a couple hundred years, Gensler had this to say:  "Somebody in the 19th century invented street lights, somebody invented stop signs, somebody invented traffic lights."

And that probably raised costs just like regulation of derivatives may do. "Just like a street light protects you from dark and dangerous highways, we need something to protect us from the dark and dangerous market that right now is over-the-counter derivatives," he said.

Asked about the Goldman Sachs trader who's been in the headlines in recent days, Gensler said he would not comment on any specific firm, but he reached back even further for explanation. "For thousands of years there's been good people, there's been bad people."