"The seductively suggestive title of Kołakowski’s talk was 'The Devil in History.' For a while there was silence as students, faculty, and visitors listened intently. Kołakowski’s writings were well known to many of those present and his penchant for irony and close reasoning was familiar. But even so, the audience was clearly having trouble following his argument. Try as they would, they could not decode the metaphor. An air of bewildered mystification started to fall across the [Harvard] auditorium. And then, about a third of the way through, my neighbor—Timothy Garton Ash—leaned across. 'I’ve got it,' he whispered. 'He really is talking about the Devil.' And so he was."
Tony Judt on a Harvard lecture of 1987, in "Leszek Kołakowski (1927-2009)," The New York review of books 56, no. 14 (September 24, 2009): 6 (6-7). More of value follows: "It was a defining feature of Leszek Kołakowski’s intellectual trajectory that he took evil extremely seriously. Among Marx's false premises, in his view, was the idea that all human shortcomings are rooted in social circumstances. Marx had 'entirely overlooked the possibility that some sources of conflict and aggression may be inherent in the permanent characteristics of the species.' Or, as he expressed it in his Harvard lecture: 'Evil . . . is not contingent . . . but a stubborn and unredeemable fact.' For Leszek Kołakowski, who lived through the Nazi Occupation of Poland and the Soviet takeover that followed, 'the Devil is part of our experience. Our generation has seen enough of it for the message to be taken extremely seriously' [("The devil in history," My correct views on everything (St. Augustine's Press, 2005), 133)].
"Most of the obituaries that followed Kołakowski's recent death at the age of eighty-one altogether missed this side of the man. That is hardly surprising. Despite the fact that much of the world still believes in a God and practices religion, Western intellectuals and public commentators today are ill at ease with the idea of revealed faith. Public discussion of the subject lurches uncomfortably between overconfident denial ('God' certainly does not exist, and anyway it's all His fault) and blind allegiance. That an intellectual and scholar of Kołakowski's caliber should have taken seriously not just religion and religious ideas but the very Devil himself is a mystery to many of his otherwise admiring readers and something they have preferred to ignore."