September 2009

Beth Harrington


The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive? by Peter Ward

"Is Life on Earth Ultimately Self-Destructive?" asks the subtext to Peter Ward's provocatively-titled new book. My answer after wading through it is that I am not really sure. Ward, a professor at the University of Washington and an astrobiologist for NASA, coined the term 'Medea Hypothesis' as a dissenting scientific perspective to James Lovelock's popular Gaia hypothesis. Named for the "Goddess of the Earth" in Greek mythology, the Gaia hypothesis maintains: "that Earth life [] will have the effect of maintaining planetary habitability by affecting the external environment in such a way as to keep it within specific limits dictated by various tolerances and requirements of life."

Ward "semi-jocularly" named his hypothesis after "one of the worst mothers ever," Jason the Argonaut's wife, and briefly relates the legend of how she killed their children to avenge herself against him. His belief is thusly that evidence culled from the geological and biological record of planet Earth indicates that the majority of catastrophic occurrences that eradicated life on our planet were caused by the very mechanisms of one life form destroying the conditions necessary for other species to survive.

Ward uses examples such as the introduction of oxygen to earth as evidence that planetary conditions do not necessarily improve when nature is left to determine its own conditions. Today, oxygen is a life requirement for vast numbers of species including our own. However, when first emitted from recently-evolved microbes during photosynthesis, the buildup of this unfamiliar gas caused the death of other organisms that could not utilize or tolerate oxygen. Ward writes, "Only the children of bugs that could tolerate oxygen -- and the cyanobacteria that learned to make it, and the bugs that later learned to breathe it -- would thereafter enjoy the sunlight." One can only fathom what kinds of creatures were lost in this involuntary selection process.

The main issue with The Medea Hypothesis is that it lacks accessibility. Its contents are at once implausible and indisputable. The average reader will have enough trouble merely trying to understand the research that was presented in this book; forming an opinion on its contents seems an effort of Herculean proportions. When Ward describes innovative new research in which scientists "learned how to extract tiny fragments of cell walls and proteins from ancient rocks," I found myself simply nodding. While it is amazing to know that technological advancements have led us to the point where we can not only see our own infinitesimal cell parts but those from eons ago, I do not have the means to confirm or disprove his findings. The book's analytical criteria are so narrow that even when Ward's findings are statistically correct they seem insignificant. For example, while it is possible that the sheer number and diversity of microbe life one billion years ago represented greater biomass and diversity than is present now, can we honestly say that the Earth is in decline when it is producing creatures of greater complexity, creatures capable of even comprehending their universe?

The Medea Hypothesis is at its most understandable when it navigates philosophical terrain -- curiously enough as Ward admits that philosophy "is far from my comfort level." He describes how people's overreaching optimism leads them to accept the Gaia hypothesis, ignoring evidence that contradicts it, because it allows us to believe that our world will protect us. However, he reminds us of the Darwinian tendency of life forms to rapidly outstrip their resources and the ambition of every species to dominate all others as proof that species have developed strategies to undercut the growth of their competitors, thus decreasing biodiversity. At its best, The Medea Hypothesis' thesis balances on a hybrid of the genuine concern of environmentalists and the pragmatism of its skeptics. He acknowledges that human beings are conspiring in their own demise by polluting their environment with toxins, but much of the technology that produces these toxins was invented to combat the perils of nature. Take from the rest what you can.


The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive? by Peter Ward
Princeton University Press
ISBN: 0691130752
208 Pages

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