Who made that rule?

Fresh Air yesterday did an interview with science writer Kitty Ferguson, who has written a biography of Stephen Hawking. There was one bit where Ferguson was summarizing Hawking on how it all began (to put it as crudely as possible) and mentioned his saying that ‘god’ wasn’t necessary for it to begin. Terri Gross paused to discuss this idea, and Ferguson rebuked Hawking for mentioning it.

He was out of his depth, she said. It’s not his subject. He’s not “an expert.”

What?

Who is “an expert” on this subject? What makes anyone an expert on this subject? What is the expertise involved?

I really don’t know. I don’t know what she thought she meant. Do people think there’s an actual body of knowledge that people have that qualifies them to say god is or is not needed? Does she just mean philosophers who understand the difficulties of causality?

If it’s the second, though, it seems dubious, because surely causality is central to what Hawking does. But if it’s the first it’s just nonsense.

This is one of the last resorts of the defenders of theism and the delicate feelings of theists: the idea that amateurs don’t get to say they see no reason to believe in god. But amateurs do get to go to church and become clerics and tell everyone what to do. Who made that rule?