What exactly is biodiversity? Why does it matter? How valuable is biodiversity compared with other things that we value? What is the metric for making such comparisons? What are the best ways to protect biodiversity? How do we manage trade-offs between biodiversity and other things that we value? Opinions about these matters are ubiquitous, but real progress in answering these questions is rare. For this reason, we should welcome Biodiversity and Environmental Philosophy: An Introduction, by Sahotra Sarkar, professor of integrative biology and philosophy at the University of Texas. Sarkar does not definitively answer all these questions, but he states an important position clearly, marshals scientific and philosophical considerations in its defense, and introduces his readers to enough disparate literatures to put us right in the middle of the contemporary discussion in a range of important fields.
Sarkar does not attempt to define biodiversity, but he is not shy about telling us why it matters. Biodiversity has “transformative value,” in that our encounters with it change our “demand values.”That is, such encounters transform the content of our preferences and affect how much we are willing to pay to have them satisfied. For example, imagine someone who is completely indifferent to the fate of Neotropical rainforests but for some reason finds himself in the middle of one. He is overwhelmed with its variety and majesty, and his indifference is transformed into a strong preference for its preservation. On returning home, he immediately writes a check to the Nature Conservancy.
There are obvious objections to such a view, which Sarkar notes. Transformations can be positive or negative. Some fraction of Nature Conservancy donors might withdraw their contributions were they actually to spend time in a Neotropical rainforest slapping insects and avoiding snakes. Moreover, what is transformational for one person can leave another person cold. There is the further difficulty that transformative value may be excessively ubiquitous. Surfing, for example, has transformative value for many people. Once you can stand on the board, you're willing to pay a lot of money to go surfing anytime there is a good break, even while neglecting your job.
Sarkar tries to rule out such cases by distinguishing things that have “systematic” transformative value from those whose transformative value is incidental. Biodiversity has systematic transformative value because it is an object of scientific investigation, and science has a deep and profound effect on our demand values, in part through its relation to technology. When something has systematic transformative value, we have an obligation to preserve it. Thus, we have an obligation to preserve species (for example), though the urgency of this obligation is sensitive to the difference in systematic transformational value that different species may have. Sarkar summarizes his view when he writes, “Biodiversity is thus signally valuable because of its intellectual interest” (p. 85).
This response may find a sympathetic hearing among biologists, but developers and politicians, who are also in the business of deploying transformative values, are unlikely to be moved by it. Consumer sovereignty appears to be a systemic transformative value in Sarkar's sense, and it has led to draining swamps and building subdivisions all over the world. If this is so, then the fate of endangered species may rest on which transformative value gains precedence over the others. But this is just another way of describing the conflict between biodiversity preservation and land-use change, rather than providing a principle for resolving it.
It is hardly surprising that such large philosophical questions remain open in the wake of Sarkar's book. The author is quite aware that these are early days for work in this area, and he makes a point of registering the tentative nature of his conclusions. What he has given us is a sophisticated introduction to both the science and the philosophy of biodiversity protection, not a textbook with some pablum for conclusions. Sarkar speaks clearly in his own voice and does not pretend that there is consensus when really there is controversy. Most important, he gives his readers substantive views with which we can engage.
This is not to say that Biodiversity and Environmental Philosophy is perfect. There are many details left to be worked out and small internal inconsistencies to be resolved, and sometimes Sarkar's readings of the literature and descriptions of the controversies are themselves controversial. Because the first four chapters are a high-level introduction and contribution to environmental philosophy, and the final four chapters are just as sophisticated with respect to conservation biology, the book is surprisingly demanding for an introduction; not many readers will feel equally comfortable with all its parts. The book is also sometimes marred by the author's uncharitable characterizations of the views of others.
These minor flaws should not be allowed to obscure Sarkar's achievement. Thinking clearly about biodiversity is difficult, and conservation biologists typically just want to get on with it, while philosophers are mostly somewhere else doing other things. Sarkar has done his readers a great service by bringing his philosophical skills and biological expertise to bear on this difficult issue. While others have also made important contributions to this field (e.g., Bryan Norton, Martin Gorke, and Holmes Rolston), there is no book quite like Sarkar's. It is essential reading for anyone who wants to theorize about conservation in a philosophically respectable way, or to philosophize about biodiversity in a way that is responsive to our best science.