What Do You Think You Are The Science of What Makes You You - Brian Clegg

1

A COMPLEX WEB

In the introduction to my 2012 book The Universe Inside You, I asked the reader to stand in front of a mirror and look at his or her body, using this experience as a starting point for an exploration of wider science.* In What Do You Think You Are?, we are going to turn this idea on its head and go far deeper – discovering the scientific basis of what makes you uniquely you. What makes you different from other humans, other animals, plants or even rocks. What is it that makes up the definitive combination of factors that is you?

There are huge similarities between humans, but each is a unique organism – you included. So why is this the case? What makes you the way that you are and different from everyone else? These are questions that we can explore on a whole range of levels. It is easy but unrewarding to state that you are unique in some hand-waving fashion. For a clearer understanding we need to employ the tools of science. In his book The Scientific Attitude, Lee McIntyre discusses what distinguishes science from non-science or pseudoscience. He believes that it is ‘the scientific attitude’, made up of two simple components: empirical evidence (based on experiment or observation, rather than on theory or logic), and being prepared to change theories in the face of evidence that conflicts with them. To understand what makes you you, we need to employ such a scientific attitude.

Some would say that science is an unnecessary complication, because what make you the person that you are is your soul. Although in a number of countries the majority now have no religious belief, across the world well over half of the population are followers of one religion or another: religions that almost all say that there is more to a human being than can be explained by physical factors alone. Those holding such beliefs may refer to a soul, or a life force or a vital spark – asserting that there is something more to the makeup of an individual human than physics and chemistry, an essential ‘something’ that many believe transcends death.

There is no scientific explanation for this extra something – but for the majority of believers, the concept of a soul or its equivalent goes beyond the physical: it is supernatural. As such, by definition the soul cannot be explored by science, as science is the study of nature. If you feel that ignoring the possibility of a soul limits our ability to truly explore all that makes you you, that’s fine. There’s nothing in this book that actively counters the existence of a soul. But we can still make a fascinating journey into your individual existence based on what science is able to tell us about humans, where they came from and how they function.

At the most basic physical level, you are composed of atoms. Everything about your body, from the structure of your cells to the intricate operations of your brain, involves the interaction of atoms in both simple and complex molecules, providing a vast and intricate dance of cause and effect that comes together in the emergent principle we call life.

We perhaps should spend a moment on that ‘e’ word – emergent – because it is a very important concept, not only when thinking about life, but also when considering other aspects of you, such as consciousness. Something is emergent if it comes into being as a result of the collective interactions of components, but isn’t present in the individual components. Very few of us would consider that the atoms that make you up are alive – yet collectively, the whole person certainly is.

Life, then, is more than a collection of atoms, which would still be the same atoms if you were minced up as fine as you like and put in a large jar (try not to think about that image too closely). But clearly you could not be the organism you are were it not for the right atoms being available to make you up. Each of the estimated 7,000,000,000,000,000, 000,000,000,000 atoms in your body has to have come from somewhere.† And it will turn out that to reach you, each of those atoms has endured a remarkable journey through time and space.

In one sense, taking the atomic view of ‘you’ we have to admit that you aren’t unique. There may be vast numbers of atoms in your body, in a unique configuration, but each atom