It is also no accident, he said, that in rankings of rich nations, life expectancy in the U.S. is among the lowest.

“The U.S. spends 18 percent of its GDP on healthcare,” he said. “That’s $8,000 per family, and you can do a lot with that. But a lot of that is being siphoned off to hospitals, device manufacturers, and pharmaceutical companies.”

In a presentation focused on solutions, Marmot began by citing “Social Injustice is Killing on a Grand Scale,” a report that he wrote for the World Health Organization’s Commission on Social Determinants of Health. He agreed with Deaton’s theory of an education-based health gap, adding that women without educations are more likely to experience spousal violence.

“Inequality as a social gradient is the key to global health,” he said. “What’s at the heart of this whole exercise is creating fairer societies.”

Governments can level the playing field, he said, by providing educational opportunities across the board and making employment for all a priority. Marmot looked at cases in which governments have taken these steps — notably Great Britain, where a new Labour government came into power in 1997 and spent the next several years shifting national policies.

“At this time the gap between the poorest and the average decreased,” he said. “Inequality increased again when the new government came in 2010, but it got smaller when the government had a consistent policy to make it smaller.”

He gave a specific example of success: In the lower-class East London suburb of Hackney, the educational development of poorer children is well within the national average — far higher than it is in the upper-class city of Bath, where poorer children are often left behind.

“This isn’t rocket science,” Marmot said. “It’s better than rocket science, because it’s about children’s education.”

He proposed that governments worldwide invest in preschool programs — which he said have been shown to increase later test scores — and called for the U.S. to adopt a tax structure with more benefit to the lower 95 percent. He also suggested a crackdown on tax havens for multinationals, which amount to 5 percent of the world’s gross domestic product.

Marmot closed his talk in a defiantly optimistic spirit. “There are a lot of bad things happening in the world, but we have to believe that right, temporarily defeated, will be stronger than evil triumphant.”

Though he said that some accuse him of living in a fantasy, he said, “Come and join me in my fantasy land, and let’s dream of a fairer world.”