How the book world is taking on the false idols of our time

Which international celebrity has lent their personal support to the following beliefs? A) that a tyrant from outer space peopled the Earth with alien radioactive souls, 75 million years ago, but remains trapped in a mountain somewhere by a battery-powered force field; B) that a 35,000-year-old guru from Atlantis not only teaches occult wisdom today via a woman from New Mexico, but also knew the (female) movie star concerned as a brother during a past life on the lost continent; C) that water subject to a mystical blessing can transcend the laws of physics and cure cancer, while another sacred liquid known as Orodyne could decontaminate radiation zones such as Chernobyl; D) that the Earth's poles switch position thanks to the weight of ice every few thousand years as the planet's thin outer crust "slides around its soft and semi-fluid inner core", annihilating advanced civilisations such as that of the hi-tech navigators who mapped Antarctica 6,000 years ago and whose learning endures in fragments such as the Ottoman "Piri Reis" map of 1513?

Connoisseurs of celeb-endorsed baloney will either know by now or learn with a weary "whatever" shrug that Tom Cruise, Shirley MacLaine and Madonna answer for the first three purveyors of piffle (respectively, the Church of Scientology, the Ramtha School of Enlightenment and the Kabbalah Centre). The fourth fantasy, as outlined in Charles H Hapgood's book Earth's Shifting Crust, attracted a well-known if semi-detached promoter who dissented from some of the arguments but cared enough about the hypothesis to consent to write a foreword for the book. His name? Albert Einstein.

When airbrushed airheads lend their gossamer authority to false and fanciful beliefs about the natural world and the human past, the party of reason and enlightenment can sit back and chuckle in complacent bliss. When one of its own idols puts his vast weight behind an exercise in crackpot pseudo-scholarship, more challenging questions emerge – and that seat of reason feels a touch less comfy for a while.

True, the father of relativity, who famously flunked the entrance exam for Zurich Polytechnic, had distinct gadfly tendencies. He seems to have aimed at shocking scientific orthodoxy rather than underwriting nonsense for its own sake. Einstein also deplored the "shabby and rude treatment" the intellectual establishment handed out to Immanuel Velikovsky, the bestselling spinner of 1950s catastrophist fantasies – such as Worlds in Collision and Ages in Chaos – which supposed that wandering comets had steered the course of history.

In this new age of intellectual chaos, it looks like being a splendid self-regarding spring for hype-resistant readers. They can relish the prospect of hooting from the sofa as lean and hungry sceptics (whether academics or journalists) hunt down the peddlers of pseudo-history or pseudo-science and sink rhetorical incisors into the flabby flesh of their prey.

This chase propels by far the strongest sections of Marina Hyde's Celebrity: How entertainers took over the world and why we need an exit strategy (Harvill Secker, £11.99). Her punchy if jerky book bites hard on the media-fuelled "mission creep" that allows stars of screen and disc to lay down the law, abusing their global fame to push "quackery, unlicensed extortion and 'belief-systems' criticised for monumental exploitation" by those who really know. If you wish to catch up with Demi Moore's ardent faith in "highly trained medical leeches" ("Do you think one sucked out her brain?" Hyde asks), the powers of the 23-volume holy book of Kabbalah that Madonna presented to President Shimon Peres of Israel (you don't actually have to read it; "all you need is the energy from the letters"), or Sharon Stone and Leonardo DiCaprio's equally decisive interventions in the Middle East peace process, Celebrity will afford hours of idiot-baiting, brain-cleansing fun.

A neat complement to Hyde's romping turkey-shoot, Invented Knowledge: False history, fake science and pseudo-religions, by the US historian Ronald H Fritze (Reaktion, £19.95), goes in for a more forensic dissection of modern myths about the past. Fritze – who tells the story of Einstein's niggling sympathy for "alternative" history and geology – selects a few choice myths and fads from the fringes of scholarship. He inspects enduring canards, from the Atlantis tales that took hold after the American Civil War, through the centuries-long quest for the 10 Lost Tribes of Israel, up to today's taste for Chinese eunuch admirals whose fleet toured the entire globe in 1421, or the black-African ancient Egyptians whose profound wisdom gave Greece all its glory. Shirley MacLaine, of whom Hyde writes that "if there is a provisional wing of Hollywood crazies, then Shirley sits on its army council," merits the rare distinction of a prominent role in both books.

If Fritze seeks to unearth the social origins of the "cultic milieu" that embraces weird history, he also points to its sometimes tragic outcomes. In the American South, the far-right fundamentalists of the Christian Identity movement may have developed a mind-bendingly flaky "fusion of Paradise Lost and Star Wars" in their theology. But our smiles fade once we know what they planned – and sometimes enacted – as a violent racist underground that Fritze calls "the Ku Klux Klan at prayer". As for the 39 members of the Heaven's Gate cult who committed suicide in San Diego in 1997, they yearned to join their watching "Space Brothers", whom they thought had kick-started human evolution from afar. These victims "died for, and from, pseudohistory".

We can add some extra dishes to this picnic-spread of tonic scepticism. In a couple of weeks, David Aaronovitch will publish his abrasive critique of conspiracy theory and its real-world effects, Voodoo Histories. Dr Ben Goldacre, the gleefully abusive scourge of diet gurus, headline-chasing hacks and all other media cheerleaders for the "alternative medicine" business, has released an update of his hype-busting manifesto Bad Science (HarperPerennial, £8.99). Nor should we forget that Francis Wheen laid down firm markers – and set rigorous standards – for the principled demolition of NewAge mental slums in his 2003 primer of "popular delusions", How Mumbo-Jumbo Conquered the World.

I enjoy these polemics, and approve of the passion for intellectual hygiene that drives them. Since so much of the modern multi-platform media gives an ask-no-questions home to rubbish of all brands (Fritze dubs it "a charlatan's playground"), beleaguered journalists can take a little comfort from the wit and nous that a few of their trade devote to the debunker's task. If the metaphor were not rather off-key, we could call that task a sacred one.

Perm a vague postmodern relativism about knowledge and its pursuit with the default prestige granted to celebs in an authority-kicking era and a widespread – often justified – contempt for official versions of all kinds, and you have a fail-safe recipe for tasty tosh. We need writers to show not merely that it stinks – but that it poisons, too. As Hyde maintains, "talking bullshit is not a victimless crime". People, as Goldacre affirms in his shocking account of the way the media hyped the alleged association between the MMR vaccine and childhood autism, can die from this stuff.

Yet these militant doubters themselves inspire a doubt or two. First, Goldacre aside, they tend to choose softish targets. Fritze expends (or wastes) a substantial chunk of his book on Martin Bernal's once-fashionable "Black Athena" thesis about the Egyptian – and African – origins of Greek culture. He says next to nothing about the semi-official Creationism that surely poses the sharpest threat to a proper understanding of the distant human past in his home state of Alabama. Indeed, he even worries that liberal triumphalism in the wake of Barack Obama's victory might drive borderline fruitcakes from the mainstream "evangelical right" (which is OK, it seems) into the arms of the racist lunatic fringe.

And a faint sound of mutual back-slapping echoes round these literary temples of reason. Inside we stand, proud and fearless disciples of the truth; outside, the rogues and their rabble – quacks, stars, journos, cultists, weirdos of all stripes – wallow in pitiable delusions. Not for the first, or last time, secular rationalism runs the risk of imitating the exclusive-brethren snobbery of the sectarian faith that it grew up to oppose during the Enlightenment.

Even a thinker and artist as revolutionary as William Blake knew that a stance of haughty separation from the legends and convictions that propel the rest of erring humanity risks hubris – and even bathos. As his lyric about the godfathers (or anti-godfathers) of European scepticism puts it: "Mock on, mock on, Voltaire, Rousseau;/ Mock on, mock on; 'tis all in vain!/ You throw the sand against the wind,/ And the wind blows it back again."

They may not consider it their job, but the current crop of myth-breakers seldom seem to have a strategy for dealing with the muddled, fantasy-prone species whose credulity builds such bizarre houses of cards. Perhaps they need to cultivate an answer to the epithet – and gauntlet – flung down by the anti-progressive philosopher John Gray in the introduction to his new volume of selected writings, Gray's Anatomy: "The myth-free civilisation of secular rationalism is itself the stuff of myth."

Fritze does at least attempt to show why otherwise sane people come under the spell of risible folly. In one chapter, he traces the hilariously improbable life of a true "international man of mystery", Wallace D Fard. A shape-shifter of 127 aliases (at least), the salesman-turned-fantasist Fard was the, possibly, half-Indian, half-New Zealander founder of the Nation of Islam. Later, Malcolm X would lead this African-American politico-religious movement before he publicly rejected its teachings as a "fraud" in favour of an orthodox Koranic faith. V

C The 76 trillion years of Fard's loony-tunes cosmology offer a galaxy of hare-brained fun – such as the tale of mad-scientist "Mr Yacub", who created "inherently wicked" white people in a demented experiment that went awry. But Fritze makes plain that this sci-fi sorcery both echoes and inverts the deeply respectable belief among Victorian racists that all non-whites belonged to an inferior, "pre-Adamic" creation. And he grasps that disillusioned black migrants from the South in pre-war Chicago or Detroit would, as poverty and prejudice eroded their hopes of betterment, clutch at any social straw that promised "a sense of identity, belonging and pride".

For all its loopy lore, the Nation of Islam – in recent years commanded by the inflammatory orator and concert-standard violinist Louis Farrakhan – recruited followers with an appeal to a clean, sober and disciplined lifestyle. "Wild and crazy ideas" may attract a bigger crowd and turn a tidier profit than mainstream knowledge or doctrine, as Fritze duly notes. But there is always some human reason in the madness of the cult.

No amount of razor-tongued invective aimed at an already converted congregation of scoffers will address the heart of this matter. False beliefs meet real needs. True, it's hard to see quite how Angelina Jolie and Brad Pitt's total takeover of Namibia – complete with border controls and no-fly zone, as deliciously recounted in Celebrity – in order to have their first biological child there taps into our collective unconscious. Some twisted offshoot of the roots-worshipping, back-to-Africa imperative (a common feature of modern cults), perhaps? In any case, celebrity antics and ordeals tend to play out on a giant screen the everyday doubts and dramas that plague us all.

At present, those doubts embrace a fierce distrust of nearly all accredited systems of understanding – in religion, science, culture and even education. To have Tom Cruise set up a publicly funded Scientology "detox" unit for the September 11 firefighters (Hyde) or bigoted US fundamentalists brand their black fellow-citizens as "mudpeople" and Jews as "the seedline of Satan" (Fritze) might seem like a steep price to pay for a crisis of authority. Yet that crisis has happened, and deepened. Elegant tongue-lashings from the enlightened media or entitled academy will not alone make it scuttle away. They may even make the "cultic milieu" dig deeper into their own mushy ground.

Fritze points out that "frantic attacks" on Velikovsky in the 1950s assumed that readers would acquiesce to the "superior expertise of the scientist rather than the logical argument and convincing evidence they deployed". Even then, deference had begun to fade, and white coats – not to mention mortar-boards – had already lost much of their allure. The assaults proved "counter-productive", with Einstein among the awkward squad.

Besides, scholarship moves on – and we sceptics should always retain a capacity to doubt our own disbelief. Invented Knowledge has a side-splitting roll-call of the pre-Columbian "discoverers" of America, from the Welsh under Prince Madoc around 1170 – they left a dozen Welsh-speaking tribes, from Shawnees to Cherokees, you know? – to the 2,000-strong fleet sent by the Mandingo ruler Abubakari II of Mali in 1311. Ethnic pride, of course, nurtured all these bids to make landfall before the dodgy Genoese adventurer.

Until recently, respectable researchers also mocked the historical value of far-fetched sagas that told of ocean-crossing explorers, but which delighted Nordic migrants in their new transatlantic home. Then, archaeological finds in Newfoundland wiped the scoffers' smirk. "In fact, Scandinavian Americans were right. Norse voyagers did reach North America around the year 1000," Fritze plainly concedes, now that "indisputable archaeological evidence" buttresses the ancient tales. That yarn led to the truth.

No, this does not mean that Madonna's Kabbalistic potion will clean up Chernobyl, nor that another pole-switch in 2012 will fulfill the Mayan prophecies of doom, just in time to make a mess of all that careful Olympic planning. It does mandate sceptics to keep a small chink of empathy in the armour of our scorn. In science, as in history, far-out heresies can triumph.

Alfred Wegener, a German meteorologist with scant expertise in geology, began in 1911 to advance the apparently deranged idea that a single original landmass, "Pangaea", had split apart to form the earth's current continents. This evidence-lite nonsense attracted such outrage over the next four decades that entire conferences were held to expose it. A specialist from the University of Chicago opined, in strident rubbish-clearing tones, that "Wegener's hypothesis in general is of the footloose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories." Immanuel Velikovsky himself felt free to sneer at Wegener.

Then, from the 1950s, readings from the new discipline of paleomagnetism began to gather supporting data. "Plate tectonics" came in from the cultic cold to take up residence in the heartland of modern science. Even myth-busters and hoax-hunters need open minds. Einstein would approve.