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Soul Made Flesh

Crystal Leonard's picture

Society has had a long, controversial relationship with the brain. Currently, the fact that the brain is the organ that controls behavior and is responsible for one’s sense of self is taken for granted as universal knowledge. However, for most of human history the brain was disregarded as a “bowl of curds” (Zimmer 5), an unimportant organ with an unknown function. The events that transformed society’s opinion of the brain so drastically took place over the course of centuries, but the most important changes occurred in England in the 1600s. In his book Soul Made Flesh Carl Zimmer recounts the opinions about the brain and the soul prevailing at different points in history, starting with the ancient Greeks and ending with modern society. Zimmer focuses the most attention on the scientific developments of the sixteenth and seventeenth centuries and on a seventeenth century English physician named Thomas Willis who founded the study of the brain as we know it today.

In Soul Made Flesh Zimmer takes a much different approach to neurobiology than the one followed by Professor Grobstein. In class Professor Grobstein jumped right into the current understanding of the brain and behavior and only discussed past views when relevant to a given topic, such as Freud’s id, ego, superego in relation to the cognitive unconscious and the storyteller. In contrast, Soul Made Flesh is a historical accounting of society’s beliefs about the brain and the soul. Only the very last chapter, entitled “Soul’s Microscope” discusses modern thoughts about brain and behavior. In addition, Professor Grobstein never assigned names to anything or depended on the gross anatomy of the brain to explain behavior. Instead, the class was focused on using experimental results to create a “less wrong” summary of observations about neuronal functioning.

In contrast, the history of the discovery of the brain depended almost solely on gross anatomy and very little on rigorous experimentation. Zimmer focuses his book mostly on the fourteenth through sixteenth centuries, a time period when science had not completely separated from philosophy. During this period very few people conducted actual experiments to prove their theories, preferring to use rationalization and “thought experiments”. Those who did conduct experiments, such as Thomas Willis and his associates at Oxford University, were hindered by the limited technology of the time. Zimmer presents what few experiments were conducted and the summaries of observations created from these experiments. However, many of these summaries of observations were at least partially incorrect, and Zimmer does not present “less wrong” summaries until the very end of the book.

Despite the fact that Soul Made Flesh is not intended to teach someone the inner workings of the nervous system, it is an incredibly fascinating book that would be of great use to anyone studying neurobiology. Zimmer lucidly provides a detailed explanation of past societies’ thoughts about the brain, soul, and medicine, and why these societies held those views. This can definitely help the modern neurobiology student, who may not hold any of the same belief systems as the previous generations, relate to the past ideas. In addition, several of modern civilization’s ideas about the brain and the soul are quite conflicting, and Soul Made Flesh helps to reveal the reasons behind these contradictions. For example, it is known that the brain is the seat of all thinking, feeling, etc. However, people commonly refer to the heart as the seat of a person’s emotions and being. From Soul Made Flesh one learns that from ancient Greece through to Renaissance Europe the heart was believed to be the seat of the rational soul (Zimmer 13). Thus, despite the disproval of this idea in the 1600s, a remnant of this belief has remained and manifests itself in places like love poetry.

In addition to explaining the process of the discovery of the brain and clarifying where a lot of common contradictory mannerisms and beliefs about the brain come from, Soul Made Flesh provides an intimate look into the lives of some of science’s most prominent names. As mentioned previously, the book focuses on Thomas Willis, the founder of neurology and the man after whom the Circle of Willis is named. In the book one learns about Willis’s childhood, his religious beliefs, his involvement in the British Civil War, his experiences at Oxford, his role in the evolution of science into what it is today, his medical career, and how he came to study the brain. Zimmer writes in such a manner that by the end of the book one feels like he or she personally knows Willis.

Meanwhile, interspersed throughout Willis’s story one learns about the lives and scientific works of his associates at Oxford. These associates include some incredibly influential scientists. For example, the spokesman for the Oxford circle, as Willis and his associate natural philosophers are called, was Robert Boyle. Boyle helped transform alchemy into chemistry and was one of the first people to study vacuums. William Harvey, the physician who discovered the workings of the circulatory system, and Thomas Hobbes, the philosopher who wrote Leviathan, were mentors to members of the Oxford circle. Willis’s assistant, Robert Hooke, created the pump that allowed Boyle to study vacuums. Hooke also was one of the first to study things with microscopes and was the one to discover and name cells. Richard Lower, a partner of Willis’s, performed the first blood transfusions. John Locke, one of Willis’s students, was the first person to truly contemplate the nature and shortcomings of human understanding. William Petty, a member of the Oxford circle, was a pioneer in the field of statistics. Finally, Christopher Wren, another member of the Oxford circle, was a renowned architect, he drew extremely accurate depictions of the gross anatomy of the brain, and he invented many of the machines that allowed the other circle members to make their discoveries.

One hears these peoples’ names in literature and in school, but one never really thinks of just how impressive their contributions to modern science really were. And to learn that they were all a part of larger network of natural philosophers based in Oxford and London is incredible! It makes one realize just how revolutionary, both physically and mentally, seventeenth century England was, and how important the events of that time were to the development of modern scientific knowledge.

Soul Made Flesh allows one to form a personal attachment to these influential men, and to understand their beliefs and motives. In this book, Zimmer entertains the reader with an intimate look into one of the most important time periods for the development of neurology and science in general. He also demonstrates the constant struggle between the search for knowledge and the preservation of societal belief systems. Anyone interested in neurobiology, history, or religion’s relationship with science would gain a lot by reading this book.


Works Cited

Zimmer, Carl. Soul Made Flesh. New York: Free Press, 2004.



Paul Grobstein's picture

thinking about brain exploration

"the history of the discovery of the brain depended almost solely on gross anatomy and very little on rigorous experimentation"

A very interesting point, particularly in the context of the comparison to how our class worked.  One needs, in the long run, both observation and experimentation/story telling?