Life, the universe - what's it all about?

If you have ever fobbed off your children's "Why, why why?" questions with a deft change of subject, you might have missed a vital chance to sharpen their minds, according to Stephen Law. Although he is a philosophy lecturer, he believes academic training can actually hinder those deep and lofty thoughts. "All children are natural philosophers," he points out. "They immediately start asking questions, making connections."

Such curiosity should be encouraged, he urges. "Adults often feel uncomfortable, don't know the answer, distract children with ice cream or a treat."

His Viking hair and black leather trousers are a contrast to the expected tweed - or toga - of his chosen profession. He doesn't dress the part or play the role. Forget ponderous ideals, musty tomes and famous names: Stephen introduces aliens, brain trolls, robots, cannibals and a talking pig, all wittily illustrated by Daniel Postgate's cartoons. His new book, The Philosophy Files, pushes readers to think, not just absorb the wisdom of the ages. "It gets to grips with the biggest questions of all: where does the universe come from, is it right to eat meat, how do I know I'm not a robot, is this a dream?" he explains.

The comic touch is designed to win over teenagers and adults alike. And he speaks in common, friendly language - not ivory tower jargon.

"I was kicked out of a sixth-form college in Cambridge and became a postman there for four years. I was a very bad one," he said. City University in London welcomed him, then Oxford (Trinity and Queens). Now 39, he lives in East Oxford and lectures at the University of London. "I seem to have a bit of a gift for making ideas fun and accessible," he said. "It's not the most common trait for a philosopher. This book is not a descriptive history, like Sophie's World or Alain de Botton's Consolations of Philosophy."

Don't look to him for turgid descriptions of intellectual giants. He mentions few names and schools of thought. The ideas are what shine.

"I'm less concerned with who said what when and more concerned with what's true," he said. "It's a how-to book, all about doing philosophy, exploring the issues rather than worshipping great masters. Some people are in awe of the big names - Plato, Descartes - others like to drop them." Memorising the facts was all the rage, back in the 1980s, he explained. "But facts are useless until you know what to do with them, how to think. With philosophy you are directly sharpening those skills. It's an activity, rather than a body of knowledge."

Ever the maverick, he encourages free thought. "I'm not proposing anarchy. We need rules and laws. But we also need to think about issues, not just defer responsibility and follow the flock. The problem with the human species is that we're moral sheep."

A famous psychology experiment tested whether American citizens would ever behave the way Germans did in the concentration camps. A man in a white suit ordered them to "administer" shocks to another person - an actor, who screeched and wailed in the other room. "More than 50 per cent sincerely believed they had killed the person. They would electrocute someone under orders. We need skills to make decisions responsibly. Philosophy can teach us how to do that."

But don't expect it to solve your domestic squabbles or romantic entanglements. As Stephen points out, philosophers do not excel at practical advice. "They are scarcely more sophisticated than Miriam or Deirdre, often less. What's really valuable about philosophy is that it can sharpen skills and thinking."

Chances to improve your brainpower abound, even at the cinema: "An awful lot of sci-fi thought is borrowed from philosophy, like the plot to The Matrix. An American scholar, Hillary Putnam, has been examining the idea that perhaps the world is an illusion. Do you know you're not just a brain in a vat?"

Restaurants also provide food for thought. Stephen admits to being fascinated by the arguments against meat-eating, though he is carnivorous: "People try to justify eating animals because they are less intelligent than we are. Then why not kill and eat stupid human beings?"

The Aziz, his favourite curry house, is the scene of a debate on the existence of God. Eagle-eyed Oxford readers will be able to find many such landmarks included in The Philosophy Files cartoons. The view from the top of South Parks prompts thoughts about humans' place in the universe and the Oxford skyline is the backdrop to a discussion of the moral argument for vegetarianism.

His next book - introducing the 25 biggest questions plaguing humans - is due out in spring 2002.

**The Philosophy Files by Stephen Law is published by Orion Dolphin at 6.99.