Written by William A. Harris


Review by Gunnel Minett

The average adult human brain weighs about 1.5 kg and accounts for about 2% of the adult body weight. It is very similar in shape and form for most human beings. Still it is unique to each individual. By the time a child is born the brain has billions of neurones that are wired together through trillions of interconnections into what can only be described as the most sophisticated supercomputer we can only begin to imagine. 

This book describes the journey from the fertilised egg to the moment a new human being is born, and beyond. It is written by an experimental neurobiologist, describing the development of neurobiology which has lead to the increase in understanding of human evolution as well as the human brain. 

Still, the story of how this development takes place is filled with as much drama as any Shakespearian plot. There are accounts of self-love and selfless cooperation, suicide and cannibalism, rivalry and survival of the fittest. All on the cellular level. And, fortunately for readers who are not experts in the field, the style makes the story comprehensible and engaging. 

One perhaps unintended ‘side-effect’ of this description is that it may trigger deeper and more philosophical reflections for the reader. As it soon becomes clear in the book, there is a lot of underlying intelligence in the intricate creation of all new life. It is after all on the cell level that this shakespearian drama takes place, long before a brain is developed. So there is no question of individual control or input. The ‘brain’ behind the whole evolutionary process seems far more part of the fabric of the universe itself. 

Anyone looking for an alternative creation myth must stop and reflect on how and why this is done. How everything seems to be connected following some incredibly clever blueprint designed by some unknown intelligent agent. 

One conclusion of this kind of reflection is that everyone and everything in our universe seems to be linked with everyone and everything else. If everything is connected, an obvious question is; ‘what are the consequences when one variable changes?’ As we see, particularly in the last chapters, the environment a foetus and child develops in will have an impact on the brain’s development. We are born with genetic potentials rather than certainties. Or to quote the author: “In which humans evolve human brains, and we find that the mechanisms that make brains human operate in ways to ensure that every human being has a unique mind.” (p189)

So what are the consequences of changes in our physical environment? Will our ongoing destruction of the environment we live in have a negative impact on the development from egg to adulthood? Will our endless and rapidly growing thirst for new technology make a difference to a process that it has taken billions of years to arrive at? 

The book does not answer these questions as such but it certainly triggers a lot of questions, way beyond telling the story of how life is created. Questions that all of us need to ask ourselves in a time that seems to be bringing existence on this planet to some kind of crisis point. 

Published by Princeton University Press, 2022, ISBN 978-0691211312