Leaving the EU will produce the greatest loss of freedom since the Second World War. The freedom of businesses to trade with Europe dominates politics. But I suspect the loss of the freedom of the individual to live and work where they want in the EU, to fall in love and bring home whoever they choose and, above all, the freedom to think and study what they will and where they please will be the hardest to bear.

You can see Britain’s horizons shrinking. The Liberal Democrats attempted to force ministers to commit to keeping Britain in the Erasmus programme that sends students to learn in EU universities. The government ordered its MPs to vote the motion down. One in six academic staff in higher education comes from elsewhere in the EU and science departments once had great success in persuading bright European PhD students to enrich research here. The Wellcome Trust tells me students are already looking elsewhere and we haven’t even left yet; applications from the rest of the EU for its junior fellowships have fallen by 25% since the referendum. Yet when scientists ask government to keep the movement of researchers as painless as possible, it makes the right noises but does nothing.

For decades, criticism of restrictions on freedom of thought has been dominated by conservatives. Allan Bloom’s The Closing of the American Mind (1987) was “elitist” in the sense that Bloom believed there was a canon of great works that had to be studied because they raised timeless questions and because he accepted that only a privileged few would be able to study them. But his claim that moral relativism had produced an “intellectual wasteland” hurt because it had enough of a purchase on campus life after the countercultural revolution of the 1960s to hit home.

If you were to write The Closing of the British Mind today, you would be duty-bound to take on no-platforming and academic censorship with a vigour Bloom would have applauded. But a truthful writer would say that the greatest threats to intellectual freedom, scientific research, the ability of the young to advance themselves through learning and a productive economy now come from the right.

British Conservatives say they want to limit the damage. Dominic Cummings, who wears his learning heavily, wants to recruit “data scientists, project managers, policy experts, and assorted weirdos” to the civil service. He peppers his writing with references to Eliezer Yudkowsky and “early warning systems in physics”. If you don’t understand cognitive biases and Bayesian inference, he won’t give you the time of day. Boris Johnson is doing his bit and has promised to double public spending on research and development to £18bn a year. Whatever you think of either man, you cannot deny they believe in science. Equally, ministers don’t want to pull students out of Erasmus. They are not Trumpian know-nothings suspicious of everyone who can read without moving their lips. They seem to care about Britain’s intellectual future. Yet when the moment comes for them to live up to the principles they profess to hold, they cannot make solid commitments. Their deeds belie their words.

I suspect that when the Brexit right goes dewy-eyed about British science, it is thinking of boffins in the Barnes Wallis mould, inventing bouncing bombs to defeat the Hun. It does not understand that there’s no such thing as “British science”. There’s just science. I don’t mean that as an abstract point. Science as practised in this country is international. In 2018, more than half of UK scientific papers acknowledged international collaboration through author addresses and well over 30% involved one or more EU countries. The problems that concern science are global, not national: the climate crisis, antibiotic resistance, how to contain Ebola.

The government cannot turn its words into deeds because it has not been honest with the public about the trade-offs Brexit will entail. I feel as if I have written this sentence every week since 23 June 2016 and no good it has done. But I will run the risk of boring you by repeating it because, although Britain has postponed hard questions for three-and-a-half years, it cannot postpone them forever.

Johnson wants a hard Brexit. He’s forgetting about our service sector – 80% of the economy – and concentrating on a minimal agreement that will allow trade without quotas and tariffs. The EU will demand concessions in return on labour and environmental protections, on EU access to British fishing waters, which will drive conservatives wild as they regard fishermen with the same reverence the left once reserved for miners, and on a permanent alignment with EU rules on state aid to industry, which will drive Conservatives wilder still as the British will be living under laws we had no say in making.

Pan-European scientific co-operation is dependent on a wider compromise. But how can a Brexit movement, which has never explained the need for compromise, reach an agreement without being accused of treason by its supporters? Who will dare tell them they can’t have their cake and eat it?

Saul Bellow turned his friend Allan Bloom into Abe Ravelstein and made him the hero of his last novel. The narrator encapsulated the postmodern condition that Bloom deplored by saying: “The challenge of modern freedom, or the combination of isolation and freedom which confronts you, is to make yourself up. The danger is that you may emerge from the process as a not-entirely-human creature.”

Conservatives are making themselves up. They say they believe in science, freedom and a strong and productive economy, at the same time as they believe in ignorant Brexit populism. The Tories who emerge from the process are unreal. They don’t make sense. Take them apart and you can’t fit them back together. Their hopes and promises are self-contradictory and have no chance of surviving contact with the reality of Britain’s position they have avoided for so long.

• Nick Cohen is an Observer columnist