By Alex Croft

Copyright independent

Barack Obama has lashed out at Donald Trump for “violence against the truth” following the US president’s rogue declaration that painkiller Tylenol is linked with autism.

In a sit-down with historian David Olusoga in London’s O2 Arena on Wednesday, Obama denounced the unproven claims by the Trump administration which he warned “undermines public health”.

“We have the spectacle of my successor making broad claims around certain drugs and autism that have been continuously disproved,” the 44th president told a 14,000-strong audience in London. “All of that is violence against the truth.”

Obama’s criticism was greeted by rapturous cheers and applause from a 14,000-strong audience, in the latter stages of a wide-ranging talk covering the ‘inflection point’ in Britain and the US, the deadly risks of AI, world inequality, social media, and his first-ever meeting with a boyish Mark Zuckerberg.

He had warned that we need to “train ourselves” to seek the truth and to “insist that there are things that are true and false” during an age in which artificial intelligence is distorting conventional reality.

In answer to a question about whether we are ready for the drastic transformations that will arise from the AI revolution, Obama said there is a “non-zero possibility” that we will be “bowing down to computer robot masters” in the relatively near future.

Much more likely, he warned, was the weaponization of AI to produce bioweapons such as smallpox, or by creating a “virus that gets into critical infrastructure and affects air traffic control”.

“This is being militarized and could be used as a system of surveillance and oppression at levels we have not seen before,” the former president added.

The former president called on people to not be entirely fearful of AI. He is “fairly confident” that artificial general intelligence (AGI), a hypothetical form of AI with human-level cognitive abilities, will help discover a cure for cancer. It could also solve nuclear fusion, creating zero-emission energy sources and “solving climate change”, he said.

Obama explained that AI has defined a large chunk of his later career, after he came to know major tech figures early in the AI revolution after becoming the “first digital president” in 2008.

“The first time I met Mark Zuckerberg, I thought he was somebody’s kid,” Obama recalled to ripples of laughter. “Jerry Yang of Yahoo had set up a meeting and he was standing in the corner, in Birkenstocks and a hoodie.

“I thought, ‘oh, somebody brought their kid along’. But it’s Mark Zuckerberg of ‘The Facebook’.”

Addressing the state of affairs in the US and UK, Obama directed criticism at progressive and liberal allies for failing to tackle a way of thinking that is leading to “creeping authoritarian tendencies” on both sides of the pond.

He repeated his comment last week that America is at an “inflection point” following the murder of conservative commentator Charlie Kirk, adding that it is “connected to the fork in the road in the UK”.

Towards the end of the 20th century, a large chunk of the West began to feel that “blood and soil nationalism doesn’t work, and dehumanising people that are different to us does not work,” Obama explained.

Liberals and progressives then got “complacent, we got smug”, he said, and didn’t recognise the fragility of the liberal order, particularly before the social media revolution and significant increases in migration brought about sudden “clashes of culture” worldwide.

Now, the former president said, it “feels like we may be backsliding towards that older way of thinking about the world”.

He added: “My successor [president Donald Trump], is not being particularly shy about it. The desire is to go back to a very particular way of thinking about America, where ‘we the people’ is just some people, not all people, and where there are some pretty clear hierarchies about status and who ranks where.

“That I think is not just true in the United States, you’re seeing the same phenomenon here.”

The challenge for liberals is not only to fight against the authoritarian tendencies but also to “be reflective of how is it that we lost support for that earlier vision”.

London Mayor Sadiq Khan, who the same day had slammed Trump for being “racist, sexist, misogynistic” after receiving direct criticism by the US president, was among the audience at Obama’s talk. It is part of a speaking tour across Europe, which will see him take the stage in Dublin on Friday.