Paul Quarrington’s The Boy on the Back of the Turtle is an ambitious mix of subjects and styles. On one level, it’s a simple travel story – an account of a week-long cruise through the Galapagos Islands that Quarrington took with his father and seven-year-old daughter, featuring bizarre animals and plants and some equally peculiar fellow travellers. It’s also part autobiography, as Quarrington uses the journey to reflect on the highs and lows of his life as a father and a son. Finally, Quarrington uses the historical association of the islands with Charles Darwin as a chance to meditate on such grand themes as evolution, the existence of God, the origins of the soul, and the history of the universe.

All of this would be a great combination if Quarrington wrote with the united talents of Paul Theroux, Stephen Jay Gould, and Stephen Hawking. Nobody, of course, does. And what Quarrington has left us is, predictably, uneven.

He’s at his best when he’s most personal – when he writes, for example, about family history or about quietly ushering his daughter past the dead body of an orphaned sea-lion pup. Quarrington – author of such books as Whale Music and Fishing with My Old Guy – also shows his skill for storytelling when he writes about the islands’ history.

However, we never get a clear picture of the Galapagos as they are today (not surprising, since he was there such a short time). And the more abstract and profound Quarrington tries to be, the more he struggles. He seriously advances a number of grandiose claims on the basis of remarkably flimsy arguments – claims about evolution leading to the creation of God, for example, or the original purpose of the soul being to scare away predators.

Quarrington seems aware of his limitations here. The book contains dozens of self-deprecating jokes about his lack of scientific, philosophical, and theological expertise. Instead of joking about his limitations, however, he might have been better advised to write within them.