HOWZAT

9. DEATH

Evolution’s problem with self-destruction

Why must we die? It is a question that splits biologists, and over the years, theories have been batted back and forth as new evidence comes to light. One answer is that death is simply necessary – to avoid overcrowding, for instance. But evolution doesn’t – can’t – select for a “death switch” because evolution is supposed to be all about the individual. And yet there does seem to be a death switch: researchers have managed to locate genetic switches that massively extend the lifespan of some nematode worms. Can we solve the riddle of death? Times Archive: Why die? Experiments in immortality, 1921

10. SEX

There are better ways to reproduce

Sex is everywhere, but no one knows why. It is a question that “better scientists than I have spent book after book failing to answer,” says Richard Dawkins. To Charles Darwin, the reason for the prevalence of sexual reproduction was “hidden in darkness”. All the arguments in favour of sexual reproduction are countered by stronger arguments in favour of self-cloning: asexual reproduction, where an organism produces a copy of itself, is a much more efficient way to pass your genes down to the next generation. There’s no proof that sex makes a species more resilient, or better placed to cope with change. Why is it still around? Times Archive: Darwin on the Descent of Man, 1871 Part 1 Part 2

11. FREE WILL

Your decisions are not your own

Our gut instinct, our experience, is that we make the decisions to move, to think, to eat, to steal, to lie, to punch and kick. We have constructed the entire edifice of our civilisation on this idea. But science says this free will is a delusion. According to the world’s best neuroscientists, we are brain-machines. Our brains create the sense that somewhere within them is the “you” that makes decisions. But it is an illusion; there is no ghost in the machine. What does this mean for our sense of self? And for our morality – can we prosecute people for acts over which they had no conscious control? Times Archive: Necessity and free will, 1877

12. THE PLACEBO EFFECT

Who’s being deceived?

The placebo effect used to be thought of as just a manipulation, a mind-trick. Doctors wore white coats, spoke in soothing tones, exuding confidence and medical know-how, and if they told you a pill would make you better, it would. By the time you found out it was just a sugar pill, you were feeling great, so who cares? Well, lots of people, actually, because our new understanding of placebo is messing up medicine. Some prescription drugs that were judged to perform “better than placebo” in clinical trials don’t work unless you know you’re taking them. All in all, the gold standard of medicine, the placebo-controlled clinical trial, is looking a little peaky. Times Archive: Science report: Endorphins and the placebo effect, 1978

13. HOMEOPATHY

It’s patently absurd, so why won’t it go away?

Homeopathy’s claim is that you can take a substance of dubious properties, dilute it to the point where there are no molecules of the original substance left in the sample you have, and still use it to heal sickness. Sir John Forbes, the physician to Queen Victoria’s household, called it “an outrage to human reason.” There is no justification in all of science for this idea -- and yet there remains some slim evidence that homeopathy works. How can this be? Times Archive: Advertisement: The New Homoeopathy, 1914

13 Things That Don’t Make Sense – The Most Intriguing Scientific Mysteries of Our Time by Michael Brooks is published by Profile Books, £12.99 More information at Michael's website.

Explore Books

• Book Extracts

• Book Reviews

• Books Group

• Audio Books

Times Recommends

• The 100 Best Books of the Decade
• The Times picks the 50 best paperbacks of 2009
• The conversation: James Ellroy