When I was a teenager, I came across Aldous Huxley’s The Perennial Philosophy (1945). I was so inspired by its array of mystical jewels that, like a magpie, I stole it from my school’s library. I still have that copy, sitting beside me. Next, I devoured his book The Doors of Perception (1954), and secretly converted to psychedelic mysticism. It was thanks to Huxley that I refused to get confirmed, thanks to him that my friends and I spent our adolescence trying to storm heaven on LSD, with mixed results. Huxley’s Perennial Philosophy has stayed with me through my life. He’s been my spirit-grandad. And yet, in the past few years, as I’ve researched his life, I find myself increasingly arguing with Grandad. What if his philosophy isn’t true?

The phrase ‘perennial philosophy’ was first coined by the Renaissance humanist Agostino Steuco in 1540. It referred to the idea that there is a core of shared wisdom in all religions, and to the attempt by Marsilio Ficino’s Neoplatonist school to synthesise that wisdom into one transcultural philosophy. This philosophy, writes Huxley, ‘is immemorial and universal. Rudiments of the perennial philosophy may be found among the traditionary lore of primitive peoples in every region of the world, and in its fully developed forms it has a place in every one of the higher religions.’

As Huxley argues, there is a lot of agreement between proponents of classical theism in Platonic, Christian, Muslim, Hindu and Jewish philosophy over three main points: God is unconditioned eternal Being, our consciousness is a reflection or spark of that, and we can find our flourishing or bliss in the realisation of this.

But what about Buddhism’s theory of anatta, or ‘no self’? Huxley suggests that the Buddha meant the ordinary ego doesn’t exist, but there is still an ‘unconditioned essence’ (which is arguably true of some forms of Buddhism but not others). I suspect scholars of Taoism would object to equating the Tao with the God of classical theism. As for ‘the traditional lore of primitive peoples’, I’m sure Huxley didn’t know enough to say.

Still, one can see striking similarities in the mystical ideas and practices of the main religious traditions. The common goal is to overcome the ego and awaken to reality. Ordinary egocentric reality is considered to be a trancelike succession of automatic impulses and attachments. The path to awakening involves daily training in contemplation, recollection, non-attachment, charity and love. When one has achieved ‘total selflessness’, one realises the true nature of reality. There are different paths up the mystic mountain, but Huxley suggests that the peak experience is the same in all traditions: a wordless, imageless encounter with the Pure Light of the divine.

How do we know it’s worth following this arduous path? We have to take the great mystics’ word for it. Huxley writes: ‘the nature of this one Reality is such that it cannot be directly and immediately apprehended except by those who have chosen to fulfil certain conditions, making themselves loving, pure in heart, and poor in spirit.’ However, we can try the first steps up the mountain and see what sort of empirical results we get.

Whatever else it is, The Perennial Philosophy is an extraordinary work of synthesis, and it injected a global spirituality into mainstream Western culture. Huxley condemned the ‘theological imperialism’ that appreciates only Western texts, and introduced many readers to now-familiar non-Western teachings – the Bhagavad Gita, the Upanishads, the teachings of the Buddha, Zhuang Zi, Rumi. Still, it’s quite an idiosyncratic selection of quotes. There’s a lot of Vedanta and Mahayana Buddhism, and plenty of male Christian mystics, but hardly any female mystics, only one line from Jesus, and no quotes from the Quran. In what sense, then, is it universal?

Although Huxley wrote that the perennial philosophy is ‘immemorial and universal’, his book was a product of a particular time and place. In the first half of his life, Huxley was known as an irreverent mocker of religion, ‘the man who hates God’ as one newspaper put it. He was the grandson of Thomas Huxley, a renowned Victorian scientist who ridiculed Christian superstitions and suggested that evolutionary science could be something like a new religion.

Huxley’s cynical exterior broke down in the 1930s. He could no longer handle living in a materialist, meaningless universe. But rather than convert to Christianity, as peers such as T S Eliot did, he turned to the scientific spirituality of his friend Gerald Heard, the BBC’s first science journalist. Heard thought that psychology and other sciences could provide an empirical evidence base for spiritual techniques such as meditation. This empirical spirituality (my phrase) appealed to Huxley.

He and Heard became leading figures in the pacifist movement of the 1930s. But they abruptly abandoned hope in Europe, and moved to Los Angeles in 1937. For a while they, along with the novelist Christopher Isherwood, became prominent members of the Vedanta Society of southern California (Vedanta is a form of Hindu mysticism). They were nicknamed ‘the mystical expatriates’ by another such expat, Alan Watts. When the Second World War broke out, they faced a lot of criticism back in Britain for their ‘desertion’ to Hollywood.

‘A society is good to the extent that it renders contemplation possible for its members’

I suspect the mystical expats felt deeply guilty for abandoning their friends and families in Europe. This is apparent in some passages of The Perennial Philosophy, which was written during the war:

Agitation over happenings which we are powerless to modify, either because they have not yet occurred, or else are occurring at an inaccessible distance from us, achieves nothing beyond the inoculation of here and now with the remote or anticipated evil that is the object of our distress. Listening four or five times a day to newscasters and commentators, reading the morning papers and all the weeklies and monthlies – nowadays, this is described as ‘taking an intelligent interest in politics’; St John of the Cross would have called it indulgence in idle curiosity and the cultivation of disquietude for disquietude’s sake.

The Perennial Philosophy was Huxley’s desperate response to the war. This explains the book’s deep political pessimism – he had tried to stop the war and failed. Modern civilisation, he writes, is ‘organised lovelessness’; advertising is ‘the organised effort to extend and intensify craving’; the 20th century is ‘The Age of Noise’. Most people are in thrall to various forms of idolatry and ersatz-religion – worship of progress, worship of technology, and above all worship of the nation-state. These, for Huxley, are all forms of ‘religions of time’ – which put their faith in future triumphs. Abrahamic religions are also, largely, religions of time (he argues) which is why they have led to so much bloodshed.

‘The reign of violence will never come to an end,’ Huxley writes, until ‘most human beings’ accept the perennial philosophy and recognise it as ‘the highest factor common to all the world religions’. The only way we can wake up from the nightmare of history is by focusing on the ‘Eternal Now’. This requires a complete overhaul of society to install a new infrastructure of contemplation: ‘a society is good to the extent that it renders contemplation possible for its members’. This looked an unlikely prospect, so Huxley withdrew to the Mojave Desert to try to become a saint.

Alas, total selflessness turned out to be hard to achieve. The Perennial Philosophy is a splendid encyclopaedia of mysticism, but that’s not the same as first-hand mystical experience. Huxley’s son Matthew wondered, after his father’s death: ‘Did Aldous ever achieve [transcendence] or not; that’s the question I’m raising. Or is it all intellectualised, put down in technical terms and other people’s words as in The Perennial Philosophy?’

It was only in May 1953 that Huxley felt he finally had a mystical experience. And that was when he took mescaline, a psychedelic drug found in the peyote cactus. He discovered a ski lift up the mystical mountain. Psychedelics, he believed, gave ordinary people a glimpse of experiences once confined to saints, and helped intellectuals like him go beyond conceptual thinking. He also got out of his head through somatic practices such as Tantra, Gestalt therapy, the Alexander technique. He even celebrated ecstatic dance. He seemed to relax and become more at peace with himself in the 1950s – friends such as Isaiah Berlin came away struck by a sense of his goodness. With this relaxation came an optimism that civilisation might not be headed for collapse. Perhaps the perennial philosophy might become popular after all.

That’s precisely what happened in the years after his death. Throughout the 1960s, the perennial philosophy was championed by figures such as Huston Smith and Ram Dass, both of them friends and fans of Huxley’s. It was promoted in places such as the Esalen Institute in California and celebrated in pop culture by everyone from John Coltrane to the Beatles. Before he died in 1963, Huxley became a hit on US campuses, lecturing on mystical experience to thousands of fascinated students. He appears on the cover of the Beatles’ album Sgt Pepper’s Lonely Hearts Club Band (1967), and even inspired a band name – the Doors.

Today, the fastest-growing religious group in the US is the ‘spiritual but not religious’, who account for 27 per cent of the population (up 8 per cent in five years, according to Pew Research). Like Huxley, this group practises spiritual techniques from many different religions – yoga, mindfulness, plant medicine – and seeks to test out these methods with empirical science. A majority of American Christians, again according to Pew, now believe other faiths can lead to heaven. There’s been an extraordinary contemplative revival – one in three Americans have tried yoga, and a quarter of Brits have tried meditation. There’s also been a renaissance in psychedelic research in the past decade, inspired by Huxley’s once-scandalous assertion that psychedelic drugs can lead to mystical experiences.

The ‘mysticism for the masses’ that Huxley prophesised seems to be coming to pass. According to surveys by Gallup and Pew, the number of Americans who say they’ve had one or more mystical experience rose from 22 per cent in 1962 to 49 per cent by 2009. It’s likely they will become more common if and when psychedelics are legalised.

And yet, for all its popular influence, some scholars of religion have dismissed Huxley’s perennialism. The first counterblast was made by the US philosopher Steven Katz in his paper ‘Language, Epistemology and Mysticism’ (1978). Katz pointed out that mystical traditions are actually very different. They are rooted in differences of language, symbolism and culture; if you try to remove ‘mystical experiences’ from that local soil and create a global synthesis, you end up with something stripped of much of its meaning. Christian mystics have Christian mystical experiences, Buddhists have Buddhist mystical experiences, and so on.

Instead of ‘many routes, one peak’, Ferrer suggests ‘one ocean, many shores’

It is true that Huxley equates ideas that are, on closer inspection, often quite different. And his global, transcultural spirituality is very individualistic and deracinated – there’s no sense of the mystical life being rooted in communities, with particular practices, rituals and guides. At the same time, Katz suggests that we can never escape our cultural conditioning, and should all just stay in our lane. The great mystics were themselves syncretistic pick ’n’ mixers – St Augustine loved Plotinus, St Teresa of Ávila loved the Stoics, the former Archbishop of Canterbury Rowan Williams loves Buddhism. Why shouldn’t we be syncretistic too? Katz ignores the extent to which mystical traditions can be shaped by our common neuropsychology (mystics were the great psychologists of their day, Huxley suggested). Many mystical practices are based on the cognitive theory of the emotions – the idea that our ordinary self is constituted by habitual automatic beliefs, which we can notice, explore and change. It’s not surprising that they discovered similar techniques for self-transformation.

The second major critique of perennialism came in 2002, with the book Revisioning Transpersonal Theory by the Spanish-born psychologist Jorge Ferrer. He points out that perennialism is hierarchical and thereby potentially intolerant. All religions are true, but some are truer than others.

This ranking of religions is apparent in Huxley’s writings. He insists that ultimate mystical experiences are moments of non-dual pure consciousness – beyond any concepts of ‘I’ and ‘you’, beyond emotion, beyond language, image and culture. That’s important for his political goal of uniting humanity under the perennial philosophy – all nations and colours will bleed into one in the Pure Light of the divine.

But in fact, many famous mystical experiences are highly emotional I-thou encounters with the divine in a particular form: Jehovah, Krishna, the angel Gabriel and so on. This is troubling for Huxley, because it opens the way for disagreement and conflict, so he insists that ‘there are good mystics and bad mystics’. Good mystics such as the German theologian Meister Eckhart (1260-1328) experience ego-dissolutions into the Pure Light, while bad mystics have passionate I-thou encounters. By this definition, Moses, Jesus, Mohammad, St Theresa, St Francis, Rumi and anyone in the tradition of devotional mysticism is a bad mystic. This is a bit rich from someone who never had a mystical experience except on drugs.

Perennialism also over-emphasises individual experience, according to Ferrer, which can lead to spiritual narcissism and thrill-seeking (this is all too obvious in the psychedelic community). It can be self-validating – the proof of the philosophy is the special experiences of the saints. This ignores what the Canadian philosopher Ian Hacking calls ‘looping effects’ – mental and somatic experience often takes the form we expect it to take. Huxley, for example, decided on one LSD trip that love is ‘the primary and fundamental cosmic fact’. But that’s what he expected, or hoped, to discover. As his friend Bertrand Russell retorted, why declare one state of mind ultimate and not another.

Finally, Ferrer argues that perennialism is objectivist and essentialist – it insists that there is a reality of spiritual facts waiting, out there, to be discovered. This is a form of ‘subtle Cartesianism’, Ferrer says, that ignores how humans construct reality through our bodies, our rituals, our words, actions and cultures.

The alternative, for Ferrer, is ‘participatory spirituality’. Humans co-create reality in a participatory interaction with the mystery. This takes place not through ‘experiences’ in an individual’s head, but through events and encounters that might involve many people (think of the Pentecost), and that could go to many possible destinations: ‘the various traditions lead to the enactment of different spiritual ultimates’. Instead of ‘many routes, one peak’, he suggests ‘one ocean, many shores’. It’s reminiscent of the Marvel multiverse: ‘You’re going to the Pure Lands? Great, I’m off to Valhalla!’

Ferrer’s participatory turn is fascinating, and very influential in intelligent New Age culture today. But it has limitations. Perhaps this is a product of San Francisco, where Ferrer’s California Institute of Integral Studies is based, but his philosophy tries so hard to be tolerant and non-hierarchical, it ends up in a ‘open, permissive horizon of transpersonal encounters’. This sounds less like God’s banquet, more like a swingers’ party. As in the Dodo’s race in Alice in Wonderland, ‘everybody has won and all must have prizes’. If you can’t handle any hierarchy, then you end up in a liberal relativism that can be just as intolerant as more traditional theories.

Ferrer is aware that this is the weak point of his argument, and repeatedly insists that we can still evaluate between different choices – between, say, joining a Quaker group or a criminal cult such as the Manson Family – by assessing a tradition’s ‘emancipatory power’. How well does it combat egocentrism, how well does it ‘counteract dissociation from the body and other aspects of the whole person’, and how effectively does it ‘foster ecological balance, social and economic justice, religious and political freedom, class and gender equality, and other fundamental human rights’?

In short, how well do spiritual traditions fit with the values of San Francisco liberalism. Why pick these values rather than others? If there is no ultimate reality, no truth, why are these the criteria for our spiritual choices? Ferrer is betraying a Western, liberal bias. Some sort of ranking or hierarchy is probably inevitable if one is to avoid complete relativism.

Secondly, I am uneasy with Ferrer’s suggestion that there are many ‘spiritual ultimates’, rather than the one ultimate reality suggested by most spiritual traditions. What about the afterlife – do we all experience the afterlife we expect? Do humanists get born once then die, Christians get born once then go to eternal heaven or hell, and Buddhists get born repeatedly? Ferrer says reality is co-created by humans and ‘the Mystery’ but his multiple realities seem very human-made, diminishing the divine in its power, glory and independence from us.

Even perennialists don’t agree on one version of the perennial philosophy

It is useful here to bring in an argument made by the US philosopher David Bentley Hart in The Experience of God (2013). It’s a surprisingly perennialist book for an Eastern Orthodox theologian (it credits Huxley’s Perennial Philosophy as an inspiration). Hart argues that critics of theism confuse gods with God. The spiritual multiverse might be full of many different powers and gods that we can connect to and manifest in different ways. But they are not ultimate, they are temporary beings or powers, like the rest of us. God, by contrast, is Being itself, the unconditioned eternal essence from which existence derives and on which all universes depend.

Being could take many forms, depending on our state of mind and cultural expectations, and it could play with those expectations. But it is still One, the Unconditioned, which we can encounter not just through mystical experiences, but also through logical deduction from the strange facts of Being and consciousness.

Still, agreement between all religions is possible only on such lofty abstract principles, which, as the English theologian Keith Ward writes in Religion in the Modern World (2019), are ‘too vague to be the basis of real religious commitment’. Even perennialists don’t agree on one version of the perennial philosophy. Huxley himself shifted during his life, from a more austere Vedanta-influenced perennialism to a more relaxed, body-accepting Mahayana/Tantric perennialism.

Ward suggests a way forward, in a world of competing religious faiths, which treads a line between intolerant exclusivism and anything-goes relativism. One could call it sympathetic inclusivism (my term, not Ward’s). This view suggests that it’s good to have a spiritual community to practise with, and one spiritual path to commit to, otherwise you end up splashing around in the shallows, never really getting anywhere. It’s inevitable that you think some paths are better than others, and that will lead to judgment of some people’s choices – I am intolerant of human sacrifice, for example. It’s probable that you’ll think your path is better than others. Otherwise, why follow it?

However, any literate or curious person can’t help but notice the interesting similarities between different traditions’ spiritual techniques – I am struck by the similarities between Stoicism and Buddhism, for example. We can learn from other paths and travellers along our way, and recognise the wisdom (perhaps divine wisdom) in other traditions. We can meet practitioners from other faiths in friendship, as the Dalai Lama meets with his friend Desmond Tutu.

Crucially, we can always remember that God/ultimate reality is greater than any of our religions, that human understanding is limited and prone to error and sin (particularly the sins of overcertainty, arrogance and intolerance), and we will probably all be surprised along the way. Interreligious dialogue isn’t just a nice extracurricular activity, in this view – it’s an essential part of our journey beyond our biases, deeper into truth.

Not everyone will accept this sort of inclusivism. Some will insist on a stark choice between Jesus or hell, the Quran or hell. In some ways, overcertain exclusivism is a much better marketing strategy than sympathetic inclusivism. But if just some of the world’s population opened their minds to the wisdom of other religions, without having to leave their own faith, the world would be a better, more peaceful place. Like Aldous Huxley, I still believe in the possibility of growing spiritual convergence between different religions and philosophies, even if right now the tide seems to be going the other way.