A recurring criticism I've face in this series is that I talk about religion but focus almost exclusively on the Judaeo-Christian tradition. In some ways that's fair, but given my concerns are with the broader features of religious belief, not the minutiae of doctrinal differences, I'm pretty confident that all or at least most of my main points apply to the monotheistic religions at least, and many are also relevant to others.

Nonetheless, it is true that several eastern religions look very different indeed, at least superficially. Could it be that those of us with spiritual urges unable to get any satisfaction from the Abrahamic faiths should head east in search of enlightenment?

Many certainly find it appealing, with Buddhism especially tempting. One of the main reasons is that there is a widespread belief that it is more of a philosophy than a religion, and that being without God, it requires us to buy into fewer – perhaps even none – supernatural beliefs than Christianity, Judaism or Islam.

As a matter of historic and sociological fact this appears to be wildly mistaken. This becomes painfully evident if you care to look. Just watch Werner Herzog's documentary Wheel of Time and you'll be disabused of any notion you might have that Buddhism is not up to its neck in superstition.

It came home to me when I visited the first Tibetan Buddhist centre to be established in the west, Kagyu Samye Ling in Dumfriesshire. It was dismaying enough to find electric-powered prayer wheels, but much worse to discover that for a minimum donation of £500 you can have your remains buried in the Stupa, which is supposed to contain a grain of the Buddha's bone. The ceremony that accompanies the placing of the remains involves "empowerments and prayers for purification and blessing of the ashes (Ru cho) with three days of prayers for the dead, and for dispelling of obstacles, called a Drupcho". This is "the appropriate procedure for ensuring a good rebirth".

Buddhism emerged out of the same Vedic tradition as the polytheistic Hinduism, which is rich in supernatural thinking. From this, Buddhism inherited a number of beliefs that are starkly at odds with naturalistic thinking. The most obvious of these is karma. I've heard Hindus, Buddhists and Hare Krishnas bravely try to insist that karma is an entirely scientific principle, being "simply the extension of Newton's law" that "for every action there is an equal and opposite reaction". But this is grasping at straws: Newton's three laws of motion concern the conservation of energy in a physical system and can only be extended to morality by either analogy or wild distortion.

There is no escaping the fact that Buddhism is full of, as the philosopher Owen Flanagan put it, "superstitious nonsense" and "hocus pocus". Yet Flanagan has written a brilliant book in which he asks the question of what we have left if Buddhism is stripped of its supernatural elements, "naturalised, tamed, and made compatible with a philosophy that is empirically responsible, and that does not embrace the low epistemic standards that permit all manner of superstition and nonsense, sometimes moral evil as well, in the name of tolerance". This would not be "authentic" Buddhism, and Flanagan says he doesn't much care if we don't call it Buddhism at all. But it could it be a coherent life-view nonetheless?

Flanagan's slightly tentative conclusion is that it can. And this is what I think makes it different to many other religions. Take away the empty tomb and Christ is just a moral teacher. Take away Gabriel revealing God's exact words to Mohammed in the Qur'an and you're left with a deluded or deluding cult leader. Take away karma, rebirth, nirvana, deities, oracles, reincarnated lamas and the like for Buddhism, however, and you still have a set of beliefs and practices to cultivate detachment from the impermanent material world and teach virtues such as compassion and mindfulness.

But here's the rub. The reason Buddhism can be so naturalised is because, stripped of its supernatural elements, its core teachings can be giving a sound, secular philosophical interpretation. In other words, it becomes a religion acceptable to the contemporary, naturalistic mind only when it ceases to be a religion.

You might think this begs the question as to whether religion has to be defined in terms of having a supernatural element. I don't think it does. If a world-view is entirely describable without loss in atheistic, secular terms, then there is nothing of substance you add to the understanding of it by describing it as religious. An adjective that fails to describe anything should not be used.

The border between the natural and the supernatural, religion and philosophy, may not always be clear. But there are lines and we should know and accept which side of it we are on.

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