Eight lessons and carols for godless people, Bloomsbury Theatre, London

Rational festive cheer with the godless squad

Before this gathering of comedians, musicians and scientists to celebrate their own Holy Trinity of Christmas – namely the secular, the rational and the scientific – I felt that what I was about to see was as much a kind of alternative Royal Variety Performance as it was a revamped Royal Institute Christmas lecture, as the show had been billed.

The first thing that the MC and curator of the event, Robin Ince, did was to give voice to that thought, adding: "Later we will have the cast of Hollyoaks singing about wave-particle duality." Ince's intro then set out to provide some thematic basics and laid into the Darwin-deniers he had stumbled across on YouTube: "if they say 'no Darwin, no Hitler' that's a bit like saying 'no Newton, no gravity', 'no Pythagoras, no Toblerone'."

While some of the subsequent acts were more relevant than others to the gathering, Ricky Gervais was the "celebrity" turn. He rarely seems to do well in short time slots and used this one to tell an off-message and off-colour joke about raping a pensioner. As Ince said after Gervais departed the stage: "Ricky did say that his set would be as much about science as Politics [his last but one tour] was about politics."

The remit of a celebration of the wonder of the universe was an easier brief for Chris Addison, a comedian whose routines are obsessed with rational thought processes. After his overture about evolution and the similarity between chimps and humans ("we both like a cup of tea after moving a piano, don't we?") he celebrated language and imagined how it may have originated from a prehistoric cave couple becoming so agitated with each other that the grunts gave way to exasperated exchanges: "My mother warned me about you!" "Oh really, how?"

If tonight was partly about reaching for the stars above our caves and then explaining them – as Richard Dawkins did with a reading from his book Unweaving the Rainbow, and mathematician Simon Singh did with his breezy tour round the Big Bang theory and how it impacted on the lyrics of Katie Melua – it was also about star turns.

The two stand-out performances came from Stewart Lee and Tim Minchin. Lee started with his first ever joke about how he was using hard drugs to get over his dependence on born-again Christianity. He went on ironically to knock the fact that the Godless shows had multiplied to three nights, with a comment about the "creeping consumerism of secularism", before giving Dawkins the best back-handed compliment he could by saying that he had started to believe in God, creationism and intelligent design because what else could have created something as "complex and intricate as Professor Dawkins?"

Meanwhile, Minchin's superb beat poem about debunking the beliefs of a woo-meister, or pseudo scientist, really got to grips with the message of the evening. "You can't know anything, knowledge is merely opinion," says his nemesis, to which he asks whether she uses that basis to select which exit she leaves the house in the morning, the front door or the window on the first floor. Further into the poem the value of homeopathy was put under the microscope with the familiar conclusive cry of the sceptic that successful alternative medicine is, in fact, known as medicine. This neatly dovetailed with the previous act, journalist and doctor Ben Goldacre, who gave a stark account of the dangers of "vitamin peddlers" in relation to the suppression of antiretroviral treatment for Aids. That Minchin's turn came after what was understandably a segment that teetered on the emotional and angry was all the more impressive.

Minchin's underlying plea for hard evidence was a theme adeptly taken up by Gavin Osbourne who was by far the most relevant and effective musical turn of the evening, singing that leaps of faith are best taken by those who can fly.

What did fly was the three hours of the show itself, and while some of the other turns were merely passable – Josie Long's too obvious and Richard Herring's a little wasteful – it mattered little, as enough, dare I say it, faith had been built up to send the audience home with Christmas cheer.