The new year is traditionally a time when people tend to look back and try to work out where it all went wrong – and how to get it right in the future.

This time the Edge Foundation asked a number of leading scientists and thinkers why they had changed their minds on some of the pivotal issues in their fields. The foundation, a chat forum for intellectuals, posed the question: “When thinking changes your mind, that’s philosophy. When God changes your mind, that’s faith. When facts change your mind, that’s science. What have you changed your mind about? Why?”

The group’s responses covered controversial issues, including climate change, whether God or souls exist and defining when humanity began.

Todd Feinberg
Professor of Psychiatry and Neurology, Albert Einstein College of Medicine in the US

“I have come to believe that an individual consciousness represents an entity that is so personal and ontologically unique that it qualifies as something that we might as well call ‘a soul’.”

He previously believed that the notion of a soul was a fanciful religious invention but became convinced that the brain and the mind could be regarded as separate, though dependent, entities. He says that the soul dies with the body.

Daniel Gilbert
Professor of Psychology, Harvard

“Six years ago I changed my mind about the benefit of being able to change my mind. The willingness to change one’s mind is a sign of intelligence, but the freedom to do so comes at a cost.”

In 2002 he and Jane Ebert discovered that people were usually happier with decisions that they could not change because they concentrated on the positive aspects. When thinking about reversible decisions they were more objective. The finding, he said, suggested that marriage could prompt love, so he proposed to his girlfriend: “She said yes, and it turned out that the data were right: I love my wife more than I loved my girlfriend.”

Roger Schank
Psychologist and computer scientist, Engines for Education Inc.

In the 1970s he was convinced that machines as smart as people would be created within his lifetime. But the complexities of human thinking have persuaded him he was wrong. “AI in the traditional sense will not happen in my lifetime nor in my grandson’s lifetime,” he said. “Perhaps a new kind of machine intelligence will one day evolve and be smarter than us, but we are a long way from that.”

Patrick Bateson
Professor of Ethology, Cambridge

A confirmed agnostic, he was converted to atheism after attending a dinner where he tried to converse with a woman who was a creationist.

“For many years what had been good enough for Darwin was good enough for me. Not long after that dreadful dinner, Richard Dawkins wrote to me to ask whether I would publicly affirm my atheism. I could see no reason why not.”

Laurence Smith
Professor of Geography, UCLA

As a believer in global warming, the reports by the Intergovernmental Panel on Climate Change and droughts in the US hardened his conviction that man-made climate change was real. “The sea ice collapse changed my mind that it will be decades before we see the real impacts of the warming. I now believe they will happen much sooner.”

Richard Wrangham
Professor of Biology and Anthropology, Harvard University

“I used to think that human origins were explained by meat-eating. In a rethinking of conventional wisdom I now think that cooking was the major advance that turned ape into human. Cooked food is the signature feature of human diet.”

Timothy Taylor
Archaeologist, University of Bradford

“Where once I would have striven to see Incan child sacrifice ‘in their terms’, I am increasingly committed to seeing it in ours,” he said. He felt that relativism had a role to play but should be limited because researchers had a duty to employ moral discrimination when assessing ancient cultures. The Incas, he said, must be understood as having had a sadistic leadership.

Rupert Sheldrake
Biologist, London He came to the conclusion that scepticism was a weapon rather than a virtue after watching creationists employ it to denigrate theories on fossils, natural selection and evolution. “Is this because they are seeking truth? No. They believe they already know the truth. Scepticism is a weapon to defend their beliefs by attacking their opponents.”

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