"I don't recall a lot of people crying when we wiped out smallpox."
-Me
circa 1993
The second hour of the Diane Riehm show today was devoted to a discussion of the Endangered Species Act, how species get listed as "endangered," the effect of doing so and whether it is appropriate to take economic factors into account when deciding whether to place a species on the list or not. I only came into the program about half-way through, but I caught a caller who was upset that the Congressman (I didn't catch which Congressman) was arguing that we absolutely should take into account potential job losses and economic diminishment when making the "moral decision" over whether to attempt to save a species from extinction.
The call very forcibly reminded me of a similar conversation I had with a few friends years and years ago, back when I was still in school. We were having lunch and one of my friends asserted that humans have absolutely no moral right to cause the extinction of any species, and that if a species goes extinct either through our actions or our inactions then we are morally culpable.
I took issue with this statement, despite the fact that I consider myself an environmentalist and am generally in favor of not seeing any species driven off the planet. What made my friend's opinion risible to me was not the result she sought to achieve by her argument, but the way she got there:
"I don't think I can agree with that," I told her, "of course we have the moral right to eliminate some other species, given the appropriate circumstances."
"Like what?" she asked.
"Well, like if that species is a threat to us, especially if that species is an existential threat to us. In fact, you can disregard morality completely to get to this point. Nature itself is all about species competing for resources, and if there are not sufficient resources for two species to cohabitate then the better adapted species survives and other dies off. If you are concerned about 'preserving the environment' then I think you have to recognize that extinction is just as much a part of the ever-evolving 'environment' as is every living species at any given time."
"Oh, that is just bullshit. Look, we're the dominant species on the planet right now and we can basically do whatever we want without threat that some spotted owl or something is going to wipe us out. You're just making an argument to justify letting us do what we want to anyway . . . pillage and loot the world around us and turn it into a cinder."
"No, I'm not, I'm just pointing out that 'saving species' isn't necessarily an issue to be resolved through a moral lens. I don't recall a lot of people crying when we wiped out smallpox." (Years later I would see a similar point being made in a funnier way by P.J. O'Rourke, but I'm telling you I came up with the joke first.)
* * *
I still think this is right. For example, right now there is a concerted effort being led by the Carter Center to wipe out the Guinea Worm in Africa. Basically, guinea worm larvae are found in stagnant water which is then drunk by humans. Once in the human body, the larvae mate, the male dies, and the female burrows into the body and begins to develop larvae of her own. About a year later the infected person begins suffering an extremely painful, burning sensation as the adult female starts to emerge from the skin. A blister develops, usually in the leg or foot, and the worm erupts from it. Very often, in order to seek relief, the afflicted person plunges his or her leg/foot into a stream or pond, at which point the worm releases hundreds of additional larvae and the cycle begins all over again. Without surgery, the only way to remove the worm is to wrap it around a stick as it emerges and wait. The process can take weeks or months and is said to be agonizing.
Now, the Guinea Worm is actually a specific species, Dracunculus medinensis, and we are working very very hard to drive it to extinction. You see, the Guinea Worm cannot complete its life cycle unless it has a human host. So in order to eliminate the Guinea Worm all we need to do is break that life cycle by preventing people from becoming infected by the worm in the first place. If that can be achieved (and progress is looking good; the Guinea Worm can now be found in only four impoverished African countries) then the worm will be unable to reproduce and the species will die off entirely.
Curiously, I don't recall seeing a lot of environmentalists rallying and lobbying hard to prevent the Carter Center from eliminating this species. Which they really should be doing, or at least the ones who claim it is always immoral to drive a species to extinction should be. And yet . . . absolute silence.
And, seriously, think about what it would mean for those who see preserving other species as a "moral act" to really stand by that principle in this case. The Guinea Worm cannot survive without human hosts. In order to preserve this species (supposedly the moral thing to do) someone is going to have to allow themselves to become infected with these parasites and suffer the agonizing pain that is guinea worm disease. Are these moralists up for the job? Or perhaps they would prefer the poor people in Africa to continue to function as this particular species's breeding ground?
* * *
The answer, of course, is obvious. In this situation the correct choice is to eliminate the Guinea Worm, drive it to extinction and wipe it off of the planet. Given the amount of suffering the worm produces I think you could argue that eliminating it is the moral choice as well, but morality needn't come into it. You can reach the same conclusion on a strictly utilitarian basis: the Guinea Worm inflicts huge pain and produces no positive effects, so a simple cost/benefit analysis demands that it be destroyed.
* * *
Now, obviously, concluding that wiping out or saving another species doesn't really present a moral issue still doesn't give us carte blanche to do as we please. Even if you look at this strictly through a utilitarian lens, getting the cost/benefit analysis of this decision right can be a real bitch.
Everybody has heard the term "food chain." I think they used to -- hell, maybe they still do -- teach about the food chain in elementary school. It is presented as a linear predator/prey relationship. For example, plants grow and are eaten by rabbits; the rabbits are hunted and eaten by snakes, snakes are consumed by coyotes. That is an example of a simple food chain. (Sometimes it's brought full cycle: the coyote dies and his body rots and becomes nutrients for the vegetation to grow).
The reason the "food chain" concept sticks around is because it is an easy concept for us to envision. Humans really only intuitively understand linear concepts, one direct cause leading immediately to one direct effect. But almost nothing works like that in the Real World.
In the Real World, systems -- whether they are naturally occurring systems, like ecosystems, or man made systems, like our national electrical grid or the World Wide Web -- are all complex systems. In a complex system, each part interacts with more than one other part at the same time, self-referential loops may be created within the system, and amplifying effects may occur such that the slight disturbance of a single part of the system can have a huge impact on the system as a whole, including the system's complete destruction.
Humans are not naturally equipped to intuitively understand this, or even to keep the myriad connections in any system in mind at the same time. Until recently, the most we have been able to do when looking at something as complex as an ecosystem is to painstakingly gather empirical data about each individual species in the system and about how each individual species interacts with each other. We could then create complicated diagrams or flowcharts outlining the connections between each species. And that was neat, but it was static; it only presented -- a most -- a snapshot of what the system looked like at a given time. But the sheer size of the number of connections and interconnections between all of those species meant that we were incapable of calculating what would happen to the network over time if it were disturbed slightly. We were unable to calculate projections.
It is only within the past few decades, thanks to our ever-increasing computational power, that we have been able to upload data about particular systems, create mathematical codes to describe how each species interacts with each other, and run computer models to test out what effect a particular change to one part of an ecosystem might have on the system as a whole. Of course, these models are only as good as the data they contain, so if our data are wrong or the relationship between species is not precisely understood, the projected result may in no way accurately reflect what would really occur. But it's a start.
* * *
One of the neater things about the study of complex systems is that we can get "meta" about it. What I mean is that while we may be a long way from understanding how a particular complex system works, by conducting statistical analyses on many systems and many types of systems we can draw up some general rules that seem to hold for all complex systems. We can then draw some general conclusions about how those systems can be affected and how resilient those systems might be to perturbations -- how stable they are.
The World Wide Web is a great example of this. The Web is a very complex system, but by its very nature it is easily susceptible to statistical analysis. What has been discovered about the Web is that it demonstrates a connectivity that seems to arise, naturally, in any complex system. For example, the Web demonstrates a great deal of redundancy; the pathways for surfing from page to page on the Web are manifold, so that if any particular pathway is blocked you can still get to the page you want to go to through another pathway. (This kind of pathway redundancy appears to exist in our own brains, by the way, which are also complex systems). This tends to make the Web highly resilient in the face of a randomly attacking computer virus.
On the other hand, the way in which connectivity is distributed throughout the Web means some websites -- individual nodes in the system itself -- are what I call "cornerstones." Cornerstone nodes in the World Wide Web are websites that are connected to a very high percentage of the other websites in the system. (For example, at least at the time I was first reading about complex systems -- about 15 years ago -- a portion of the Web had been analyzed and the Amazon website was one of these "cornerstone nodes.")
Generally speaking, the connectivity of particular nodes in complex systems follows a Power Law, which means that the most connected node will have a certain number of connections, the next highest connected node will have a lesser number of connections, the third highest connected node will have a lesser number of connections, etc., and that the loss of connections as you go down the list proceeds at a steady rate (for example, Node 2 has 3/4's the the number of connections of Node 1, Node 3 has 3/4's the number of connections of Node 2, etc., etc., all the way down).
This explains why the Web is so resilient to random attacks. The vast, vast, vast majority of websites just aren't very highly connected. So a random attack on any particular site (like this one) is unlikely to produce much in the way of systemic damage.
But note that this only holds true for random attacks. The flip side to this type of resilience -- resilience in the face of a random attack -- is systemic vulnerability to intentional attacks. The drop-off in connectivity according to a power law means that there is a relatively small (relative to the system as a whole) number of "nodes" that the system relies upon to provide a great deal of that system's overall connectivity. The small number of these important nodes within the system as a whole means that the odds of them all being taken out randomly is quite low; but if they were specifically targeted then the effect on the system itself could be catastrophic. The destruction of only a few "nodes" means a large portion of the system's connectivity is lost. This means the rest of the "nodes" in the system get cut off from each other, and the system itself may even collapse.
* * *
Which brings me back to ecosystems. Remember, it appears that all complex systems automatically get structured the same way. Using the discussion above as an analog, we can say with some degree of confidence that in any particular ecosystem there will be a handful of truly important species (nodes) that provide the vast amount of "connectivity" that permits the ecosystem to continue functioning as a whole. The rest of the ecosystem's constituent species -- the huge, huge majority of the ecosystem -- will not display this type of connectivity, and their elimination will probably have a negligible effect on the ecosystem itself. But if one of the cornerstone species goes, the system itself will be seriously disrupted and might even fail.
The problem is that we really don't know how any particular ecosystem, or the global ecosystem as a whole, works. Not really. We've got a lot of empirical data and we've got some computer models, but we don't really know how well we can rely on our data and we don't really know how closely our models match up to Real Life. Which means that we can't really know, in any given instance, whether any particular threatened species is a cornerstone species or not. However, understanding the basic rules governing complex systems does lead to a few conclusions:
(1) The good news is that, because only a tiny number of species provide the connectivity necessary to keep the system functioning, the odds are against us doing widespread systemic damage if we accidentally wipe out one or two.
(2) The bad news is that this means that we're just playing the odds and getting lucky. Sooner or later, if we keep going, we will wipe out a cornerstone species and that will result in a significant change in the environment. Since we live in the environment too, this might not work out very well for us.
(3) The worse news is that as more and more species get wiped out randomly, the odds of wiping out an important cornerstone species increases. If there is only one cornerstone species in a system of 100, then the probability it is randomly wiped out is 1%. But if you've already wiped out half the species population without hitting this one, the odds you hit this one next are 2%. Two percent may sound low (and it is, this is why complex systems are so resilient), but it is still double what you started out at, and given the potentially serious result should a cornerstone species be wiped out you probably don't want to go around doubling your odds that snake-eyes is going to come up next.
(This alone presents a very good argument for the general rule that we should be trying to preserve as many species in an environment as possible. The greater the number of existing species, the less the chance that if one of them is accidentally wiped out, it turns out to be the one that the system is really counting on.)
(4) The ironic news is that it is extremely unlikely that the species that we get most exercised about saving -- the spotted owl, the gray wolf, the elephant, the Bengal tiger, the orangoutang, the panda -- are all that important from a systemic point of view. Sure, their elimination would suck a lot of the aesthetic beauty from the world and make it a drabber place, but these large animals are basically the consumers of their ecosystem, the ones we still think of as sitting at the top of the "food chain"; they don't have a whole lot of other species depending on them. What is probably much more likely is that there is some species of grass, or even bacteria, that we don't even know about yet (and wouldn't really care too much about if we did know about it) but that is so connected and upon which everything else ultimately relies that its elimination might doom the system as a whole.
* * *
So this is why I ultimately come out on the same side of the ecology/endangered species discussion as my friend from years ago who thought this was a moral issue. I want to save species not because I think it is immoral to wipe them out, but because I understand that we don't - and probably never can -- have perfect knowledge about what the ultimate effect of wiping out a species will be. Sheer self-interest is enough to make me want to save endangered species.
POSTSCRIPT: The Guinea Worm, however, is a good example of what we can do if we have sufficient knowledge. Since beginning its campaign decades ago, the Carter Center has eradicated the Guinea Worm from 16 countries without ill-effect. It therefore seems very likely that if we can succeed in wiping it out completely, nothing much bad will happen. Screw the Guinea Worm.
No comments:
Post a Comment