Are Tortoises Better Than Goats? Darwinian Ethics in the Galapagos

For some years now, the National Park Service of the Galapagos Islands has sponsored programs for the mass killing of pigs, donkeys, and goats on the islands.  For example, over a five year period, over 140,000 goats were killed on two islands--Santiago and northern Isabela Island.  The killing of these and other animals is justified by the claim that these "invasive" species must be eradicated to protect the "native" species, such as the Galapagos giant tortoises, marine iguanas, and finches.  The goats are so voracious in eating vegetation that is necessary for the diet of the native species that the native animals could eventually be driven to extinction if the goats were not killed.

As an ecotourist looking forward to my first tour of the Galapagos, I agree with this, because I would rather see giant tortoises than goats.  But by what moral standard do I judge that tortoises are more valuable than goats?  The farmers who introduced these goats to the islands might not agree with me.  In fact, in recent years, some of the residents of the islands have staged violent protests against the policies of the National Park Service that threaten their livelihoods.

Darwin observed the drastic environmental changes that can come from introducing goats and other imported species into isolated island.   When he visited the island of St. Helena in the South Pacific on his way back to England on the Beagle, he was surprised by the "English, or rather Welsh character of the scenery" on this island, and he discovered that this was because plants imported from England had driven out the native vegetation.  Goats were introduced in 1502.  And within two hundred years, the feral goats had destroyed all the young trees in many areas, while creating fine pasture land.  In 1731, an order was issued to kill all the stray animals, but by then "the evil was complete and irretrievable" (The Voyage of the Beagle, National Geographic Society, 2004, pp. 432-35).

But why was this "evil"?   After all, in the light of the evolutionary theory that Darwin later developed, we could say that when a new species flourishes at the expense of the native species of an island, this is just survival of the fittest!

By what moral logic do we defend the "native" species of an island against competition from "invasive" species?  The very language of "native" and "invasive" is dubious, since all of the "native" species on the Galapagos are descendants of earlier invaders, who arrived sometime after the islands were formed by volcanic activity.

Sometimes ecologists imply that there is a "balance of nature" that is upset when pristine ecosystems are "invaded" by species that don't belong there.  But if we accept the viewpoint of Darwinian evolution, living nature is never in balance or fixed but ever in a state of flux as species compete with one another, and there is no cosmic order of nature by which we can judge that one species belongs here and another species belongs there.  I would rather see tortoises than goats in the Galapagos.  But that's not because tortoises rank higher in the Great Chain of Being than goats, or because there is some cosmic or divine design by which tortoises belong in the Galapagos and goats do not.

If we think this through, we are led back to one of the major implications of evolutionary science for moral judgment.  If there is no moral cosmology for determining right and wrong--including the proper place or rank for living species--then our moral judgments must be rooted in our human experience--in our human desires.  If the good is desirable, then the good is variable for different species, and there is no cosmic standard of good and beyond beyond the natural desires of each species.

So for Darwin, what the goats did to St. Helena was "evil," because it frustrated his intellectual desire as a natural scientist to see and study the original flora and fauna of that island.  Similarly, the ecotourists will travel thousands of miles to see the tortoises of the Galapagos, and so if they saw that the goats had made the islands inhospitable for the tortoises, they would be disappointed, because they want to see what Darwin saw.

Some environmentalists would complain that I am being too anthropocentric in my environmental ethics, because I am assuming that the value of all living beings is determined by the instrumental value in satisfying human desires.  These environmentalist say that we need an ecocentric or biocentric ethics that recognizes the intrinsic value of all living beings without reference to human desires.  But I find this implausible, and I see it as contradicting the evolutionary science that environmentalists generally accept.

I wrote about this some years ago in a paper on "Aldo Leopold's Human Ecology" (in Charles Rubin, ed., Conservation Reconsidered, Rowman & Littlefield, 2000).  The ecocentric environmentalists claim to be following the lead of Aldo Leopold, particularly in his classic of environmental ethics A Sand County Almanac (1948).  But I argue that this is wrong because Leopold consistently embraced an anthropocentric ethics rooted in the moral-sense tradition of ethical philosophy as developed by Adam Smith and David Hume and adopted by Charles Darwin. 

As the evolved social and moral animals that we are, we can extend our moral concern to nonhuman animals and plants, and perhaps even to whole biotic communities that include soil, water, plants, and other animals, which Leopold called the "land."  But that moral concern will always be anthropocentric in the sense that it is centered in our human desires.  If the "land" has any value for us, it's because it satisfies our intellectual, moral, or aesthetic desires. 

So if we want to eradicate the goats from the Galapagos to protect the native species from their competition, it's because we have been persuaded that this is more desirable for us.  If we disagree--the farmers want to have their goats, and the environmentalists want to have their tortoises--then we will have to struggle to find some mutually desirable resolution.  The environmentalists might persuade the farmers to see the economic benefits of ecotourism.  Or we might strike a balance between some areas devoted to farming and other areas preserved for the ecotourists.

But in no case can we resolve our dispute by appealing to some cosmic or divinely designed order of value that is not rooted in the human good as the humanly desirable.