Everybody needs money. That's why they call it money.

From full global headquarters, this is Motley Fool Money.

It's the Motley Fool Money Radio Show. I'm Chris Hill. This week we revisit one of our most popular interviews.

Earlier this year, Motley Fool's CEO Tom Gardner sat down with bestselling author Michael Lewis to talk about his book Flash Boys, a Wall Street Revolt.

In it, Lewis explores the secretive world of high-speed trading and they begin by talking about a big problem with the stock market.

Can I just start? Are you ready?

Yeah. Rather than you ask me a question, this is great.

Before we went on camera, you just said, and a fool is a good thing.

You just triggered a thought that the experience of writing this book has hammered home.

It's that a big part of the problem in the stock market right now has been that investors did not want to acknowledge their ignorance about how the stock market worked.

So they're willing to believe the noise that came out of broker's mouths about how electronic trading worked.

And everybody is still to this moment.

And not just investors like small investors, but like CEOs of large mutual fund companies.

The heads of mutual funds, the heads of pension funds, the big hedge fund managers, that the thing that they get quickly offended by, coming out of my mouth say, is the idea that the hero of my book explains to them how the stock market now works.

Even though that's what happened. That two or three years ago, they had no idea how they were being front run by by high frequency traders.

This guy comes and explains they respond by saying, oh my god, I can't believe this is happening.

Flash forward now. And when they tell the story, oh, I knew most of what was happening. He helped me round out my understanding.

And it's funny that this is, it's a problem in finance.

And I don't know quite why it's a particular problem in finance.

The idea that ignorance is a sin. And so everybody's terrified about not knowing when it's such an unhealthy.

I'm not defending finance by asking this, but what industry is ignorance not a sin?

I mean, obviously it's maybe the greatest sin in finance where you're essentially, in many cases, in finance acting as salesperson.

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