Jack Cohen (1933–2019): The Polymath of Reproductive Biology and Xenobiology
Jack Cohen was a rare breed of scientist: a rigorous laboratory biologist who possessed the expansive imagination of a science fiction novelist. Over a career spanning six decades, Cohen transitioned from a leading expert on reproductive development to a celebrated public intellectual and "alien-maker" for some of the world’s most famous authors. His work bridged the gap between the microscopic mechanics of sperm and the cosmic possibilities of extraterrestrial life.
1. Biography: From Norwich to the Stars
Jack Cohen was born on September 19, 1933, in Norwich, England. His fascination with the living world began early, often characterized by a hands-on (and sometimes messy) approach to nature. He pursued his higher education at the University of Hull, where he earned his PhD in 1957, focusing on the complexities of development and reproduction.
His academic trajectory was primarily rooted in the English Midlands. He spent nearly 30 years as a Lecturer and later a Reader in the Department of Zoology and Comparative Physiology at the University of Birmingham. After "retiring" from Birmingham, he became an Honorary Professor at the University of Warwick, where his collaboration with the Mathematics department birthed some of his most influential interdisciplinary work.
Throughout his life, Cohen was known for his eccentric and high-energy teaching style. He famously kept a wide array of exotic animals in his laboratory and home—ranging from octopuses to mantis shrimps—using them as living visual aids to explain the staggering diversity of evolutionary solutions to life's problems.
2. Major Contributions: Sperm, Extelligence, and Xenobiology
Cohen’s intellectual contributions can be divided into two distinct but related phases: his "hard" biological research and his later philosophical and speculative work.
Reproductive Biology and Sperm Selection
In the 1960s and 70s, Cohen challenged the prevailing view of fertilization. While many saw fertilization as a race won by the "best" sperm, Cohen’s research suggested a more complex "selection" process. He observed that in many species, the female reproductive tract actively filters out the vast majority of sperm, many of which are structurally or genetically "wrong." His work highlighted the massive redundancy and high error rates in gamete production.
Xenobiology (Exobiology)
Cohen was a pioneer in applying the rules of terrestrial biology to the "possibility" of alien life. He argued against "Star Trek" style aliens (humans with forehead ridges) and pushed for "xenos" that evolved under different constraints but followed universal principles of complexity and energy management.
"Extelligence"
Coined alongside mathematician Ian Stewart, this concept refers to the cultural and technological knowledge stored outside of human brains (in books, rituals, and digital networks). Cohen argued that human consciousness is a product of the interaction between internal "intelligence" and external "extelligence."
"Lies-to-Children"
Cohen and Stewart popularized this pedagogical concept: the idea that complex subjects must be taught via simplified models that are technically "false" but provide a necessary stepping stone to deeper understanding.
3. Notable Publications
Cohen was a prolific author of both textbooks and popular science books.
- Living Embryos (1963): A classic textbook on developmental biology that remained a staple for university students for decades.
- The Privileged Ape (1989): An exploration of human evolution that questioned our "special" status while highlighting the unique cultural mechanisms that set us apart.
- The Science of Discworld Series (1999–2013): Co-authored with Terry Pratchett and Ian Stewart. These four volumes use Pratchett’s fantasy world as a backdrop to explain real-world physics, biology, and history.
- Figments of Reality (1997): An ambitious work with Ian Stewart exploring the evolution of the human mind and the nature of reality.
- Evolving the Alien (2002) / What Does a Martian Look Like? (2002): A deep dive into the constraints of evolution and how they might manifest on other worlds.
4. Awards and Recognition
While Cohen did not seek the traditional accolades of the scientific establishment (like the Nobel), he was highly decorated in the realms of biology and science communication:
- Fellow of the Royal Society of Biology (FRSB): A recognition of his lifelong contribution to the biological sciences.
- The "A" Award: Given by the Science Fiction Foundation for his contributions to the genre.
- Honorary Degrees: He received recognition from various institutions for his work in public engagement with science.
- The Jack Cohen Prize: Established in his honor to recognize excellence in biological research and communication.
5. Impact and Legacy
Jack Cohen’s legacy is defined by his refusal to stay within a single "silo."
In biology, he is remembered for his skepticism of oversimplified evolutionary narratives. He reminded his peers that evolution is often messy, redundant, and counter-intuitive.
In science communication, he revolutionized the "science of..." genre. Rather than simply pointing out errors in fiction, he used fiction as a "hook" to teach complex emergent systems. His influence on the Science of Discworld series helped millions of readers understand the difference between "narrative imperative" and scientific causality.
In speculative fiction, he acted as a "biological consultant" for giants like Larry Niven, Jerry Pournelle, and Anne McCaffrey. He ensured that their aliens were biologically plausible, influencing the "hard" science fiction movement to move beyond humanoid tropes.
6. Collaborations
Cohen’s most significant partnership was with Professor Ian Stewart, a mathematician at the University of Warwick. Their "Jack and Ian" partnership was legendary for its synergy, combining Cohen’s biological intuition with Stewart’s mathematical rigor.
He also shared a deep friendship and professional bond with Sir Terry Pratchett. Cohen was one of the few people allowed to "play" in the Discworld sandbox, and Pratchett frequently credited Cohen with providing the biological "logic" that underpinned his fantastical creations.
7. Lesser-Known Facts
- The "Zarathustra" Project: Cohen spent years designing a fictional planet called Zarathustra, complete with a fully realized ecosystem, just to demonstrate how "non-human" life could be while remaining scientifically sound.
- The Exploding Lecturer: He was known for a lecture demonstration involving the "bombardier beetle," where he would simulate the beetle's chemical explosions, sometimes resulting in singed eyebrows for those in the front row.
- Microscopy Art: In his early career, Cohen was an expert in electron microscopy. He viewed the microscopic world not just as data, but as a source of profound aesthetic beauty, often comparing the structures of cells to gothic architecture.
- Consultancy: He was the secret architect behind the biology of the "Dragons" in Anne McCaffrey’s Dragonriders of Pern series, helping her explain how a large flying creature could realistically breathe fire (via the ingestion of phosphine-bearing rocks).
Jack Cohen passed away on May 6, 2019. He left behind a world that understood itself a little better—and a universe of imagined aliens that were far more interesting because he had lived.