After days of pressure on No 10 to sack Andrew Sabisky, one of Dominic Cummings’ recently appointed “weirdos and misfits”, the self-styled “superforecaster” took to social media to resign last night. In his resignation tweet he said he hoped the “media learn to stop selective quoting”. However, when put in its proper context, Sabisky’s track record is far more damning than the out-of-context quotes for which he has been criticised, leaving Cummings and Downing Street with serious questions to answer.

The press rightly seized on his comments about race “science” and IQ, enforced contraception and support for eugenics (the concept of improving the genetic health of humans by excluding “inferior” genetic groups and promoting “superior” ones). But it’s just as important that we pay attention to where he made those comments – in the online world of alt-right subcultures that fellow Hope Not Hate researchers and I have been exploring in our latest book The International Alt-Right: Fascism for the 21st Century?. Even though Sabisky himself is gone, the milieu in which his views developed has not.

Many of the most prominent individuals pushing modern race science have come from within the international alt-right. One of the niche pseudoscientific theories popular in such circles is “human biodiversity” (HBD), which argues that there are differences in intelligence between races, based on genes – despite this theory being repeatedly debunked. A key figure within the so-called “HBD-o-sphere” is a blogger called “HBD Chick”. And it was on her website that Sabisky wrote, in 2014, that “there are excellent reasons to think the very real racial differences in intelligence are significantly – even mostly – genetic in origin, though the degree is of course a very serious subject of scholarly debate”.

Equally revealing is the title of the blog under which Sabisky made his comment: “in the dark about the dark enlightenment”. The Dark Enlightenment is a name given to a far-right movement that promotes a little-known ideology called neo-reaction or NRx. This is a largely online, far-right political subculture that emerged over the past two decades from the broader “reactosphere”, taking shape as bloggers realised that their views on gender, race, religion, governance and much more all shared a rejection of the liberal democratic attitudes that had grown in the west following the Enlightenment. Sabisky wrote that “the Dark Enlightenment is a silly and hyperbolic term for what should be fairly uncontroversial at this point”, yet most people would be disturbed by its core NRx ideas.

Neo-reaction is a very strange, marginal and extreme far-right ideology. It foresees a shift from globalised, multicultural liberal democracies with Enlightenment principles to competing states, run by dictatorships or monarchies, where ethnic groups live apart to ensure they are “preserved” and humans are transformed using sophisticated technology. Taking inspiration from NRx “thinkers” such as Nick Land and Curtis Yarvin, the NRx movement see this as not just unavoidable but also desirable.

Though best thought of as a disparate blogosphere rather than a cohesive movement, it has acted as both a tributary into the alt-right and as a key constituent part. While it does not share the public profile of the broader alt-right – the NRx community is essentially limited to small, obscure forums and blogs – it has found adherents and supporters in big tech and Silicon Valley.

There is evidence to suggest that Sabisky is even more broadly sympathetic to the NRx movement. In a 2017 blog for the International Business Times, he lamented Twitter’s clampdown on the infamous meme Pepe the Frog, which has long been used as a mascot for alt-right and far-right groups to spread racist, Islamophobic and antisemitic content online. In the article, he praised Land, the philosopher and amphetamine enthusiast considered the founding father of the NRx movement. Previously an academic at Warwick University in the 1990s, he went on to become a core NRx figure after publishing an online manifesto entitled The Dark Enlightenment in 2012. He acquired something of a cult following while becoming increasingly racist and propagating very far-right ideas. Yet Sabisky writes, “The present writer has followed Land for the last few years, and never once has his conduct been anything other than entirely praiseworthy.”

It’s clear, too, that Sabisky has spent some years reading and commenting on alt-right websites. In 2014, he commented on an article on the Unz Review, a website popular with alt-right racists and antisemites that has run Holocaust denial and pseudo-race science and hosts a blog by Steve Sailer, the alt-right’s go-to person on race science, who is often credited with coining the term “human biodiversity”.

Looking at the evidence, it starts to appear that Sabisky may not just hold unacceptable and abhorrent views in isolation but that he may actually be a neo-reactionary or alt-right believer. The idea that someone from these movements managed to become an adviser to Downing Street, if only briefly, is genuinely shocking and further evidence of how once marginal alt-right ideas have crept towards the mainstream.

• Joe Mulhall is head of research at Hope Not Hate