The Edinburgh International Book Festival ends today, and on Sunday night it offered a very rare double-whammy of literary stardom, with an event for Haruki Murakami followed directly by Martin Amis.

Whereas Murakami's fascinating event ranged from his musical inspirations to whisky and the deliciousness of seaweed, Amis's session largely addressed the far more stark subject of human evil.

And taking questions from the audience, the leading author said that he believes that the Islamic State (IS) militant movement will have disintegrated by this time next year.

The writer, who is 65 today, said the violent movement, which is in control of areas of Syria and Iraq, will "fizzle out."

Amis, whose latest book, The Zone of Interest, is set, like his novel Time's Arrow, in the Holocaust, said that historically it had been thought that "wars of religion" were over.

Ideology, he said, had taken over from religion as a cause for war during the 20th century.

These political ideologies, he said, had acted like a 'methadone' to religions 'heroin'.

But now, he said, religious war appears to be back.

Amis added: "Now nothing is so weird and so nasty that it cannot occur, and now [this violence] is in the name of religion, these beheadings, these tentative genocides," he said.

"Islamism is different in that it is an ideology within a religion, so it is doubly potent and doubly terrifying.

"All you can say is....Leninism and Stalinism lasted through the lion's share of a century, Hitler was over in 12 years, Pol Pot in three years, I don't think Isis is going to be around next year, I mean deep into next year.

"When something is so virulent, it sort of fizzles out. That's what I hope.

"But plenty of things will come in to replace it."

Amis, in the session conducted by the expert hand of The Herald and Sunday Herald's Alan Taylor, said he did not believe that human beings were fundamentally flawed, or naturally evil.

"The human being is good," he said.

"When they get together, that's when you have trouble."