“Dead of the world, unite!” Appearing in a manifesto published in Petrograd in 1920, this arresting slogan encapsulated the philosophy of cosmism, which promoted interplanetary exploration as a path to immortality. Mixing scientific futurism with ideas derived from the 19th-century Russian Orthodox mystic Nikolai Fedorov, cosmism was summed up by the rocket engineer Konstantin ­Tsiolkovsky (1857-1935) as “the perfection of man and the liquidation of all imperfect forms of life”. Liberated from the Earth, human beings would become pure ether, bodiless and undying. The belief that death could be conquered by science was embraced by a renegade section of the Bolshevik intelligentsia, including Maxim Gorky, and informed the decision to immortalise Lenin’s cadaver – first by refrigeration, in an early experiment in what would later be called “cryonic suspension”, and then by embalming when freezing failed. Cosmist thinking went on to find a home in the Soviet space programme and continues to influence Russian science to this day.

Nearly a century after the cosmist manifesto, a group of transhumanists gathered outside Google’s corporate headquarters in Mountain View, California, carrying placards reading “Immortality now!” and “Google, please, solve death”. Death could be solved, the group believed, by the development of “cyber-consciousness” – a task requiring new technologies for uploading the contents of the human brain into cyberspace, which the group called on the tech company to fund. Google was already investing substantial resources in life-extension techniques and, in 2012, the company hired Ray Kurzweil, long associated with programmes aiming to achieve immortality through cryonic suspension, artificial intelligence and mind uploading, as its director of engineering.

History continues by being forgotten. Mark O’Connell, in recalling the February 2014 demonstration outside Google HQ, reported as “the first ever transhumanist street action in the US”, says little about the longer antecedents of contemporary trans­humanism in his engaging and at times very funny book. This is an exploration of our time, conducted by an observer who is very much of our time. O’Connell presents the reader with a gallery of diverting characters, including an Oxford-educated “extropian” philosopher who goes by the name of Max More, who aims to achieve “more life, more intelligence, more freedom” by replacing the human body with a robot controlled by an uploaded mind, and Zoltan Istvan, the transhumanist candidate for the US presidency in 2016, who conducted his campaign from an “immortality bus” decked out as a coffin.

The weird mixture of science and religion that typifies much of contemporary culture is illustrated in questing, faintly sad figures who blend transhumanist “anti-deathism” with Buddhism, Mormonism, Wicca or the UFO cult Raëlism, whose members believe the human species was created by aliens. We learn of the LSD guru Timothy Leary’s late-life engagement with transhumanism, which included membership of the cryonic suspension organisation Alcor, and that when the time came for him to have his body frozen, he opted instead to have “his cremated ashes shot into space from a cannon”. O’Connell reports that Leary’s last act “is still a sore point within the cryonics community”, which views his “capitulation to deathism” as “a significant tragedy”.

O’Connell’s impressions of the lost souls who have drifted into transhumanism are vivid and memorable. Yet he sees them from a distance that is never explained. Like many of the people he interviews, he seems to think that a report of his feelings is all that is needed to validate his beliefs and his doubts. He cites transhumanists expressing disgust with the process of ageing, in themselves and in others, and he tells us that he is not a transhumanist. But he never gives any reasons why he rejects their attitudes, nor does he offer an alternative view of his own.

The book is a succession of vignettes in which fundamental questions about the transhumanist enterprise are not explored. If the bodies of the followers of the cult are retrieved from their icy tombs, will the dead be reborn, or will what emerges be clones of human beings who had died for ever? Is information uploaded from the brain into cyberspace the essence of the human mind, or only a dim ghost of a mind that no longer exists? Is being embodied an accidental feature of the mind, or an integral part of what it means to be human?

Discussing “A Letter to Mother Nature”, a transhumanist manifesto in which Max More sets out his proposals for amending the human species, O’Connell summarises the author’s proposals:

We would no longer consent to live under the tyranny of ageing and death, but would use the tools of biotechnology to “endow ourselves with enduring vitality and remove our expiration date”. We would augment our powers of perception and cognition through technological enhancements of our sense organs and our neural capacities. We would no longer submit to being the products of blind evolution . . . And we would no longer be content to limit our physical, intellectual and emotional capacities by remaining confined to carbon-based biological forms.

O’Connell writes that the letter captured “something crucial about what made the movement so strange and compelling to me – it was direct, and audacious, and it pushed the project of Enlightenment humanism to such radical extremes . . . There was, I felt, a whiff of madness about the whole enterprise, but it was a madness that revealed something fundamental about what we thought of as reason.”

As a description of the simple-minded devotion of transhumanists to an unexamined idea of reason, this is well observed. But what is the “something fundamental” that the author has learned? He considers the possibility that transhumanism is a displaced passion for miracle and mystery, citing D H Lawrence: “Today man gets his sense of the miraculous from science and machinery, radio, airplanes, vast ships, zeppelins, poison gas, artificial silk: these things nourish man’s sense of the miraculous as magic did in the past.” But if Lawrence’s observation is well founded (as I think), what follows for the idea that human beings are or could ever be rational animals? These are questions that O’Connell does not ask, or leaves hanging in the air.

Read as a kind of travelogue, To Be a Machine contains much that is interesting and entertaining. O’Connell perceptively observes how transhumanism fits with Silicon Valley’s world-view. He describes a conference at Google HQ, attended by the billionaire entrepreneurs Peter Thiel and Elon Musk, which brought together those who want to liberate themselves from death and exponents of “effective altruism”, who aim to improve the world by using reason. There are some intriguing crossovers between the two movements.

Philosophically speaking, effective altruism is not much more than a reheated version of Jeremy Bentham’s utilitarianism. The early-19th-century thinker wanted to supplant ethical reasoning as it had been practised in the past with what he called “moral arithmetic” – a type of calculation aiming at maximising pleasure, happiness or want-satisfaction (there are many variations). Implying that every moral quandary has a rational solution, this is a project that fits well with the transhumanist belief that the evils of human life are, in essence, technical difficulties.

The idea that moral reasoning should be a type of calculation seems to have influenced Thiel and Musk when they donated to research on the risks of artificial intelligence. Some of those who attended the conference (including the Swedish philosopher Nick Bostrom, a former transhumanist who has become critical of the movement) believed that AI could even pose a risk to human survival. A super-intelligent machine could be programmed to serve human beings. But, as Bostrom, Stephen Hawking and others have pointed out, such a machine might slip free from its programming and begin to pursue ends of its own that have nothing to do with human well-being.

Such an artificial super-intelligence need not be hostile to humans; it could simply be indifferent to whether humankind survives or not. Investing large sums into research that might prevent the disappearance of humankind might seem the most rational way of allocating resources – more so than spending money helping people deal with disability, for instance. But why is reducing a hypothetical risk to the species more rational than increasing the happiness of living human beings? Utilitarian moral arithmetic prompts this question along with many others in ethics.

Both transhumanism and effective altruism claim to be rationalist philosophies and the two movements have offices in the same building in Oxford. But, like effective altruism, transhumanism is not as rational as it seems. Transhumanists believe that we are in essence sparks of consciousness which can escape mortality by detaching themselves from the decaying flesh in which they happen to be embodied. Deriving from mystical philosophies such as Platonism and gnosticism, it is an idea at odds with scientific materialism.

For a genuine materialist – say, the ancient Roman poet-philosopher Lucretius – there can be no question of the human mind severing its linkage with the material world. The mind is material and dies when the body dies. Transhumanists will reply that technologies not available in Lucretius’s time will allow the mind to be uploaded into cyberspace. Yet it is unclear whether what will be uploaded will be a conscious mind, or just a spectral app spun off from the contents of the brain.

Even if consciousness can be detached from the human body, the mind will still require a substratum of matter. The rejuvenated cadavers that emerge from cryonic suspension will be physical things, as will the cyborgs to which some transhumanists imagine their minds being transferred. Minds floating in cyberspace would not escape this dependency. Cyberspace is an artefact of physical objects – computers and the networked facilities they need – not an ontologically separate reality. If the material basis of cyberspace were destroyed or severely disrupted, any minds that had been uploaded would be snuffed out.

Every technology requires a physical infrastructure in order to operate. But this infrastructure depends on social institutions, which are frequently subject to breakdown. I made this point when I bumped into some ardent advocates of cryonic suspension in California in the 1980s. How long would it take to develop the technologies that were needed to resurrect frozen cadavers as living organisms, I wondered. Not much more than a century, I was told. I asked these techno-futurists to consider the events of the past hundred years or so – a devastating civil war and two world wars, a ruinous stock-market crash and the Great Depression, for example. Given this history, how could they be confident that their refrigerated cadavers would remain intact for another century? The companies that stored them would surely go bust, wars and civil disturbances would lead to power failures, and the legal system that protected the cadavers could disappear. The United States might no longer exist in a recognisable form. The cryonicists looked at me blankly. These were scenarios that they had not considered and could not process. Such upheavals might have happened in the past, but the future was going to be quite different. For these believers in technological resurrection, American society was already immortal.

At bottom, the transhumanist movement is a modern variant of the mystical dream of transcending contingency – the vulnerability that comes with being subject to accident and the power of events – that possessed many in ancient times. These mystics wanted to be absorbed in a timeless, impersonal absolute, a refuge from the ugly conflicts of the human world. They understood that this refuge could only be entered if they shed their individuality and practised asceticism and contemplation in an effort to erase their personal identity and desires. Less intelligent than their ancient precursors, contemporary transhumanists imagine that they can become immortal on terms of their own choosing.

Pondering a conversation he had with one of the techno-mystics, O’Connell worries that only the extremely wealthy could afford to be uploaded to a virtual world. The rest of us would have to struggle on, bombarded by messages from cyberspace trying to sell us some product for which we have become targets through our use of the internet. But, to my mind, the super-wealthy few would not be much better off.

The greatest problem with everlasting life in cyberspace is the prospect that it would have to be spent in the company of other cyber-immortals. As Max More and some of his fellow transhumanists have envisioned, each of these disembodied minds might design its virtual body and environments as it pleased. But might not these virtual environments somehow overlap or collide? Cyberspace is a projection of the human world, not a way out of it. What if the few who had escaped their ageing flesh found themselves side by side with an immortalised Donald Trump, his orange hair undyingly abundant, presiding over a ­never-ending Mar-a-Lago? It is not for nothing that the gods in some Greek myths regarded immortality as a curse.

To Be A Machine: Adventures Among Cyborgs, Utopians, Hackers, and the Futurists Solving the Modest Problem of Death by Mark O’Connell is publishes by Granta Books

Mark O’Connell appears at the Cambridge Literary Festival on 23 April, 7pm (see left)