Rarely have conflicts created such rich pickings for the media as those in Iraq and Afghanistan. A combination of smartphones, tablets, social networking and YouTube has generated a magnificent, even if occasionally grisly, assortment of snapshots and factual documentaries, blogs and autobiographies. Some have been controversial – think of Abu Ghraib – but mostly they have been flattering in espousing the heroism of ISAF forces. This is particularly true of images of human anguish beamed to our television screens by embedded photojournalists, a handful of whom, like Tim Hetherington and Rémi Ochlik, paid the ultimate price.

Despite unprecedented access, the ensuing reportage often overlooks the surreality of war by not being explicit about the conflicting experiences it generates for those involved first-hand. War is surreal for the paradoxes it mobilizes. Prominent among these (and quite aside from the surreality of the physical setting) are the want of community and camaraderie and yet the experience of competition and rivalry; the conflicting emotions of pleasure and guilt; sharp contrasts between a sense of meaning and futility. While petty by comparison, similar paradoxes may be found in the organizations that dominate much of our working lives. It may just be the case that they are easier to identify in contexts that are exceptionally austere, and where getting the wrong end of the stick kills. These conflicting experiences cannot easily be reconciled. Rather, those affected often have little choice but to reconcile themselves to them as best they can.

Alex Mitchell achieved a curious kind of fame. He died while laughing uproariously at an episode of The Goodies, a famous British TV comedy show. The sketch featured a game of ‘Ecky Thump’, a spoof martial art contest in which opponents pelted one another with black puddings and defended themselves with a set of bagpipes. Alex found it hilarious and was convulsed with laughter throughout much of the episode. He let out a huge guffaw at one particularly amusing piece and then, to the surprise and consternation of his family, suddenly stopped laughing, collapsed on the sofa and died. The story of the ‘man who died laughing’ became headline news and his wife even subsequently wrote to the Goodies thanking them for making her husband’s last moments so happy.

It was later found that Alex had a rare heart condition in which excitement can adversely affect the electrical activity of the heart, precipitating a cardiac arrest. Although it is perhaps not widely appreciated, humans are electrical machines. Everything that we think, feel and do is caused by electrical signals in our cells, from the beating of our hearts to our ability to see, hear, think, speak and move our limbs. We even define death as when the electrical activity of our brain ceases. Ultimately, this electrical activity and thus our thoughts, feelings, actions – even consciousness itself – is produced by a set of little-known but extremely important proteins called ion channels. This essay tells some of their remarkable stories and shows how Cambridge scientists played a crucial role in unravelling how the electrical signals in our cells generated.

This article is not about prison reform, death in police custody or design of medieval monasteries. Instead the cells that it concerns are the living cells that make up our bodies. Most readers will be aware that estimates of the number of human bodies on the planet reached 7 billion in 2011 and none of us has difficulty recognizing 7 billion as a simply enormous number. Therefore it may come as a surprise to discover that 7 billion cells would make up only the terminal joint of my index finger (Figure 1.1). The total number of cells in the human body is best estimated at 100 trillion, 1014. The inevitable conclusion from this is that cells are extremely small, with occasional conspicuous exceptions, like an ostrich egg, which begins as a single fertilized egg and is thus an enormous single cell.

This chapter starts by a simple introduction to the beauty and fascination of living cells. They are responsible for building all the tissues of the body, including blood, nerves, muscle, bone, yet they are all formed by progressive specialization from the cells generated by division of a single fertilized egg. This poses two extraordinary challenges. The first is the nature of the molecular mechanisms that allow cells to diverge and to specialize to fulfil particular functional niches, but the full details of these mechanisms lie outside the scope of this chapter. The second challenge is that of producing stable and balanced numbers of each type of cell within the body. How are the ratios of blood cells to nerve cells or cells that line our gut balanced and managed? This question is made all the more acute by the fact that different types of cell persist in the body for very different lengths of time. Thus the cells that line our intestines, or the cells that line the ducts that carry digestive juices from our pancreas into the gut, survive for only a few days before they are replaced by new counterparts. In contrast most of our nerve cells persist throughout our adult lifetime. Although some types of nerve cell can be formed during our lifetime, others cannot and most remain with us throughout adult life. This poses an extraordinary challenge of bookkeeping and management of cell production and replacement.

Not everything is quite as it seems

The year 2012 is – as it is becoming increasingly difficult to forget – an Olympic year. The Olympics have a long history, as we are often told, which stretches back to the world of ancient Greece. This link between ancient and modern was trumpeted again during 2012, not least at an exhibition entitled ‘The Olympic Journey’ at the Royal Albert Hall, which told the story of the Olympics from ancient Greece to the present day.

And yet, just what picture of the ancient games, and thus the links with our modern Olympics, do we have in our heads? A quick quiz highlights the issues. Which of the following did form part of the ancient Olympics?

1. (a) the Olympic torch relay

2. (b) the Marathon race

3. (c) male athletes tying up their penises with string

Only the last is true of the ancient games. The torch relay was introduced by Hitler at the 1936 Berlin Games, and the Marathon race first became part of the Olympics in 1896, at the inaugural modern games. Athletes tying up their penises with string, on the other hand, known as ‘infibulation’, ‘ligaturing’ or by its ancient name kynodesme (‘dog-tying’), was a well-known feature of ancient athletics. Its purpose is, however, unclear, with some scholars arguing that it was meant to help avoid unwanted erections, others simply to keep the penis out of the way when running, others that it was an issue of sexual attraction and others still an issue of modesty.

Be prepared

When asked about what happens next, Woody Allen replied, ‘I don’t believe in an after-life, although I am bringing a change of underwear.’ Such preparedness goes to the heart of understanding attitudes to the after-life. ‘Leave nothing to chance’ was the advice taken by the ancient Egyptians who could afford a Book of the Dead to be buried with them, even if the book factory where they bought it often misspelt their names (Taylor 2010). The words, it seems, did not matter as much as the possession of the object. As a satnav to the future such devices could never be properly tested, or returned as faulty, and many purchasers probably got stuck on the equivalent of a bridge that was too narrow in the netherworld of the dead. Nonetheless, the book which contained some 200 spells had a long shelf life, enjoying a period of popularity between 1550 and 1069 bc. It acted to overcome the dangers of the netherworld, which were many, and through which the dead person walked, floated on air or travelled by boat. Clearly the inspiration for today’s gaming industry, the many levels and dangers that the dead person encountered were overcome by the special powers of the spells that transformed them into a variety of animals and plants; and by transforming they triumphed until they reached their goal and the game was over.

After-life and after-person

As an archaeologist I could provide an historical account of the many and varied beliefs in the after-life. I could range across the cultures of the world, digging into the temporal archives to recover nuggets of information that would delight and intrigue, and which gathered together would form a facet of its creator’s after-life; read, transformed and remembered.

I begin with a thought-experiment. Imagine, to start with, the disappearance of humans from the Earth. We are eliminated, in this scenario, not by means of a nuclear war or other pan-planetary catastrophe, but rather by a Homo sapiens-specific virus, which results in the swift deletion of our species but leaves our built environment intact, and the ecologies of which we are part undisturbed other than by our absence. Imagine, in fact, for the purposes of finessing the counter-factual, that the planet’s last human perished at some point in the late winter of 2012. What then would happen to ‘the world without us’, in Alan Weisman’s phrase (Weisman 2007: 5)? Or rather – for the more precise purposes of this thought-experiment – what would happen to the city of Cambridge without us? How would the city alter over the weeks, months, years, decades and centuries following its abandonment?

Allow me to hypothecate a set of futures for this post-human Cambridge. First and fastest come the hungry fungi, even at that cold time of year. In kitchens and dining rooms, moulds bloom on food left out on sideboards and worktops, spreading their mycelial nets of grey, yellow and green. With no one to chase it away, dust settles in the windless interiors of lounges and bedrooms. Decay has started, but so in its way has stasis. In March, a late spell of winter is cast. Water freezes in pipes, and then a thaw brings floods: ceilings crash down, walls fatten, soffit boards rupture. That summer, fire follows: lightning strikes and gas explosions, leaving cratered holes and husked houses. By August, rosebay willowherb – also known as bomb-weed, because it thrives on carbon-rich soil – flowers on these blackened sites like a pink floral fire.

Introduction

A genome is the complete set of genetic instructions for an organism. For each of us, it is forty-six large molecules of DNA in the nucleus of every cell, each packaged into its own chromosome, together with many copies of a shorter fragment of DNA that lies in a specific compartment of the cytoplasm.

This genome makes us what we are, by determining, directly or indirectly, the structure of every complex molecule in our body. Together with a little help from the genomes in our parents, and our parents’ parents, it determines how our bodies are put together, and how they function, and how they interact with the myriad environmental influences before and after birth to make us what we are today.

Genomes are by no means the only, or even necessarily the best, level of organization at which to study how all these complex things happen, but they are interesting. In this chapter, I look at some of what we have learnt about life by studying genomes.

Living organisms are extraordinary. They have capabilities which far exceed any present-day technology, and it is therefore inevitable that scientists and engineers should seek to emulate at least some of those capabilities in artificial systems. Such an endeavour not only offers the possibility of practical applications, but it also sheds light on the nature of biological systems.

The notion of artificial life can take many diverse forms, and in this article we will focus on three aspects: modelling the development of structure in living systems, the quest to create artificial intelligence, and the emerging field of synthetic biology. All three topics reveal surprising, and sometimes remarkably deep, connections between the apparently disparate disciplines of biology and computer science. There is something else which links these three strands: the Cambridge mathematician Alan Turing (see Figure 4.1) whose birth centennial we celebrated in 2012.

It is widely acknowledged that Turing laid many of the foundations for the field of computer science, although amongst the general public he is perhaps best known for his role in breaking the Enigma and other cyphers at Bletchley Park during the Second World War (Hodges 1992). What is perhaps less widely appreciated is that Turing also made important contributions to biology. As we shall see, each of the three topics discussed in this paper builds on a different seminal contribution made by Turing.

The boundary between life and non-life has been the guiding principle for this interdisciplinary exploration of the notion of life. The chapters that follow start with cells, bio-electrical mechanisms, evolutionary processes and artificial intelligence. Then, in the social world, they consider work on the boundary of death, the way we have envisaged life in the distant past, the metaphor of ruined life, and how first humanity imagined going beyond life.

Cells are the minuscule bricks of life. Ron Laskey describes how living things are kept alive and healthy by the balancing of life and death among the trillions of cells of which they are made. Different functions require cells to have very different life expectations, from a few days to the whole life of the body. Each cell’s birth and death is wholly altruistic. It is determined by what is needed for the best functioning of the body of which they are so tiny a part. The scale and complexity of what is required to keep a whole organism alive and healthy stretches our imagination. At the heart of every cell’s birth is the process of division and thus replication of its DNA, an act of, in terms of man-made things, incomprehensible precision.