I’m a biologist, not a physicist or an astronomer, but these are both fundamentally important parts of science. Why the universe is here and what it’s made of, why light behaves as it does and why time travels – they are all fundamental questions. Most physicists can’t actually explain the theories of Einstein if you ask them. His theories of relativity are an attempt to explain the very big things in the universe. Is it expanding? How many galaxies are there? If there was a Big Bang are we sitting around now waiting for the Big Crunch? Then, at the other end of the spectrum, people are trying to understand the very small things in the universe – quantum theory. How energy and matter interact on a very small scale.

However, in the late part of the last century people started trying to put the two together, but they wouldn’t go. This book is perhaps the public debut of string theory – an attempt to explain how the best of the big and the small theories might be linked to explain the entire universe. The reason I think this is such a good book is that Greene does a very good job of explaining the current understanding physicists have of the universe. In other words, it’s a readable book about the universe. A Brief History of Time by Stephen Hawking is a totally unreadable book so I couldn’t include it. Nobody has ever really understood it. Brian Greene’s book doesn’t suffer from this problem.

What is string theory?

String theory says: OK, the theory about the reason the universe viewed on a very small scale doesn’t line up with the universe viewed on a very large scale is because we’re looking at the small things as particles. But when you get very small, they stop behaving like particles. They do weird things like exist in two places at once. They don’t have enough dimensions for some of the other ideas in physics to work. So, to explain the whole universe you say they’re not particles at all, they’re wiggly bits of spaghetti. If you don’t see it as a particle but as a wiggly string then apparently it explains everything. Strings have 11 dimensions and the whole universe is made up of them, so somehow this better allows them to obey Einstein’s explanations too. It allows for what we see out there to also fit in with the very, very small. It’s a mathematical fudge and a cop-out in some ways, but it’s the only theory we’ve got.

Right.

I think it’s important because it’s about how science works. I’m not a mathematician – although I’m told the maths behind string theory is very elegant. However, the whole thing is a theoretical fudge and that’s what’s so exciting about it! This is how people’s brains have to work. To be a scientist you have to be creative and imaginative. Sure, science has its stamp collecting elements and attracts some quite boring types. But science doesn’t make the interesting people boring. These are really elegant, clever fudges.

The main criticism of string theory is – it doesn’t deliver. Even though it comes close to explaining what might be going on in the universe, it has failed to make a real prediction about how the universe behaves that can be tested by a scientific experiment. That’s about as major a problem as a scientific theory can have. One critic thought it so misguided and lacking in understanding that he borrowed an old physics put-down and described is as “not even wrong”. We do need a better theory, but nobody’s got one.

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Carl Zimmer recommends:

The Immortal Life of Henrietta Lacks is about the woman who unknowingly helped create the polio vaccine and uncover the secrets of cancer. This is a fascinating book on so many different levels. It is just as compelling as the story of the author trying to uncover the history of the woman from whom all these cells came from.

Who was known as “HeLa”.

She had cervical cancer, and samples were taken from her body. Scientists who were trying to culture human cells discovered that her cells could just grow and grow and grow. It had never been seen before.

Why do you think that was?

That is one of the things that I find particularly fascinating. What happened to Henrietta Lacks is that she was infected with human papillomavirus. Now lots of people get infected with this virus. It is very common on people’s skin, for example. A lot of people carry it and don’t even know it; in some cases, it causes a small wart. But if it is spread sexually, women can develop cervical cancer from it. And it is amazing what this virus does. We usually think of viruses as infecting cells and making new copies of themselves until the cells explode and die. All the new viruses then go off and kill other cells. But that’s not what all viruses do.

I am obsessed with viruses. For me, part of the fascination with Rebecca’s book is that it the story of what viruses can do. The papillomavirus infects a cell in the skin or other kinds of lining in the body. But it doesn’t try to kill the cell, it does the opposite. It actually produces proteins that link onto the proteins in the cell and speed up its growth and division. Basically, its strategy is: If there are more host cells that are infected with the virus, that means there are more viruses.

The reason most of us can have this type of virus and not be harmed by it is that we are constantly shedding the top layer of our skin. That’s what dust is. The viruses in these cells gradually rise towards the surface of our skin, and then we just get rid of them. So they don’t hang around long enough to cause trouble. There is this nice kind of balance between the virus and the host most of the time.

But with Henrietta, there was no balance.

Exactly. For people with cervical cancer, the virus just speeds things up too much. Once you get that kind of uncontrolled growth, you have cancer. In the case of Henrietta Lacks, the virus created a kind of super-cancer, because it could not only grow rapidly in her body but also grow rapidly in a Petri dish. It is continuing to grow today, even though she has been dead for some 50 years.

But her children and grandchildren live on – and the author actually tracked them down and went to visit them, to see how they are coping.

She did. Henrietta Lacks’s family faced the strangeness of life in a very intimate way. Their mother dies of cancer, and yet years later they hear from scientists that she is actually still alive, she is in a lab somewhere. And they try to make sense of it all, which is tough because they are not scientists. Her husband only got a grade-school education.

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Jerry Coyne recommends:

The Blind Watchmaker is the original version of intelligent design. It comes from William Paley, who was a natural theologian in the 18th century. Paley wrote a book called Natural Theology to try to explain why the perfection of animals testifies to the existence of God. He says, “I’m walking across Hampstead Heath, my foot pitches up against a watch, I look at this thing and it’s marvellous. It has these cogs and gears, it tells the time and the time is correct. It is extremely well made for what it does”. Then he says, “Look at an animal”.

In my book I use the example of a woodpecker. It has a tough beak, it has stiff tail feathers to prop it against a tree, it can hit its head 15 times a second at 16 miles an hour against the trunk without hurting its brain because it has padding around its brain. Its eyes close at the moment of striking so it doesn’t get woodchips in its eyes, it has feathers in its nostrils so it doesn’t inhale woodchips. A woodpecker is the organic equivalent of a watch. Paley’s view is that since you can infer the existence of a designer or watchmaker from looking at the perfection of a watch, you must be able to infer the existence of a designer from looking at the perfection of animals and plants. That was basically the worldview of all biologists before Darwin – that the perfection of nature testified to the glory of the Creator.

That’s what Darwin changed in The Origin of Species. He showed that that perfection of design could be arrived at through a completely blind, purposeless and materialistic process. That is the reason why Darwinism is so despised by religious people. I can’t speak for Richard Dawkins, but it’s pretty clear that natural selection, which is what the book is about, is the blind watchmaker. It produces things as intricate as a watch and even more so. Any animal is infinitely more complex than a watch is, but that animal has been produced by the simple, materialistic, blind, purposeless process of natural selection. The whole point of Richard’s book is to show that we no longer need recourse to a celestial designer to explain the wonders of nature and the marvellous “design” of organisms.