Fareed speaks with Sam Harris, a neuroscientist and author of The End of Faith, about his take on extremism in Islam and the recent controversy over a panel on Bill Maher's show. Watch the full interview on GPS this Sunday at 10 a.m. and 1 p.m. ET on CNN.

One month ago, the celebrated atheist, author and neuroscientist Sam Harris appeared on "Real Time," Bill Maher's HBO show. The conversation about Islam that ensued created quite a bit of controversy. Harris said, among other things, that, "Islam at this moment is the mother lode of bad ideas." He went on to say that more than 20 percent of Muslims are either jihadists or Islamists who want to foist their religion on the rest of humanity. That comes out to about 300 million people. I beg to differ, and said as much when I responded with my own thoughts on this show. But I wanted to talk to Mr. Harris in person, so here he is. He's the author of a new book, Waking Up. And we might get to it.

Yes.

But first I want to ask you about that number...

Sure.

...which it struck me as sort of pulled out of a hat. If you do have, you know, something in the range of 20 percent of all Muslims who are either jihadists or Islamists, which implies condoning violence and such, I'm just doing the math, that comes to about 300 million.

Right.

So there were 10,000 terrorist events last year. Let's assume all of those were Muslim. Let's assume each event was planned by 100 people. Neither of those assumptions is right, but I'm being generous. That comes to about a million people who are jihadists. So that still leaves us with 299 million missing Muslim terrorists.

Yes, right. Well, there are a few distinctions I think we have to make here. One is there's a difference between a jihadist and an Islamist. And there I was talking about Islamists and jihadists together. And so Islamists are people who want to foist their interpretation of Islam on the rest of society. And sometimes they have a revolutionary bent, sometimes they have more of a normal political bent. But they do want to...

But the fact that somebody may believe that, for example, sharia should obtain and women's testimony should be worth half a man's in court doesn't mean that they want to kill people...

Well, no...

Right, those are being conservative and religious, which, by the way, is not my orientation at all. But it's different from wanting to kill people.

Yes. Well, again, you have to parse this on specific points, like do you favor killing apostates, do you think adulterers should be killed? Even among Islamists, you'd find more subscribing to one versus the other, depending on the poll you trust. But I didn't just pull the number out of a hat. There's a group at the University of North Carolina, Chapel Hill that looked at 40 years of parliamentary elections in the Muslim world – literally every election that has occurred – and found that Islamists got 15 percent of the votes.

So I would say that if you take this number 15 percent who vote for Islamist parties, and then you look at the poll results on specific implementation of Sharia law – do you want adulterers and thieves given the traditional punishment or should apostates be killed – you never find the number, with very few exceptions, you never find the number as low as 15 percent voting in favor of those punishments. It's often 60 percent depending on the society. So I believe nudging that up to something around 20 percent is still a conservative estimate of the percentage of Muslims worldwide who have values relating to human rights and free speech that are really in zero sum contests with our own. And I just think we have to speak honestly about that.