Showing posts with label extinction. Show all posts
Showing posts with label extinction. Show all posts

October 25, 2010

Jeff McMahan on eliminating carnivorism in the natural world

This is one of the most important and thought-provoking articles I've read in the New York Times in quite some time: The Meat Eaters by Rutgers philosopher Jeff McMahan.

In the article, McMahan asks the question, "Would the controlled extinction of carnivorous species be a good thing?" His conclusion is yes:
The conflict, therefore, must be between preventing suffering and respecting the alleged sacredness — or, as I would phrase it, the impersonal value — of carnivorous species. Again, the claim that suffering is bad for those who experience it and thus ought in general to be prevented when possible cannot be seriously doubted. Yet the idea that individual animal species have value in themselves is less obvious. What, after all, are species? According to Darwin, they “are merely artificial combinations made for convenience.” They are collections of individuals distinguished by biologists that shade into one another over time and sometimes blur together even among contemporaneous individuals, as in the case of ring species. There are no universally agreed criteria for their individuation. In practice, the most commonly invoked criterion is the capacity for interbreeding, yet this is well known to be imperfect and to entail intransitivities of classification when applied to ring species. Nor has it ever been satisfactorily explained why a special sort of value should inhere in a collection of individuals simply by virtue of their ability to produce fertile offspring. If it is good, as I think it is, that animal life should continue, then it is instrumentally good that some animals can breed with one another. But I can see no reason to suppose that donkeys, as a group, have a special impersonal value that mules lack.

Even if animal species did have impersonal value, it would not follow that they were irreplaceable. Since animals first appeared on earth, an indefinite number of species have become extinct while an indefinite number of new species have arisen. If the appearance of new species cannot make up for the extinction of others, and if the earth could not simultaneously sustain all the species that have ever existed, it seems that it would have been better if the earliest species had never become extinct, with the consequence that the later ones would never have existed. But few of us, with our high regard for our own species, are likely to embrace that implication.

Here, then, is where matters stand thus far. It would be good to prevent the vast suffering and countless violent deaths caused by predation. There is therefore one reason to think that it would be instrumentally good if predatory animal species were to become extinct and be replaced by new herbivorous species, provided that this could occur without ecological upheaval involving more harm than would be prevented by the end of predation. The claim that existing animal species are sacred or irreplaceable is subverted by the moral irrelevance of the criteria for individuating animal species. I am therefore inclined to embrace the heretical conclusion that we have reason to desire the extinction of all carnivorous species, and I await the usual fate of heretics when this article is opened to comment.
It's worth noting that McMahan, like a number of abolitionist transhumanists, have advocated something like this for quite some time nowa group of thinkers that includes myself, David Pearce, Pablo Stafforini, Michael Anissimov and others. David Pearce's contribution to the discussion is the most significant, and it would have been nice to have seen McMahan make mention of it.

As for me, I've argued for something even more extreme and sweeping than selective extinction or the reprogramming of predators; I've made the case that we are morally obligated to uplift the entire animal kingdom so that they may join posthumanity in postbiological existence.

With McMahan's contribution hitting the mainstream, however, I am excited beyond words. The meme is out there; now let's see where we take it.

May 12, 2007

When hypergiants go hypernova

Scientists predicted that something like this could happen, and now they have actually observed it: a hypergiant star went nova.

About 238 million years ago a star in galaxy NGC 1260 ended its life. To say that it was a powerful explosion would be a gross understatement; the amount of explosive energy expelled by supernova SN 2006gy defies human comprehension.

Prior to its dramatic death, the hypergiant star, which was 150 times larger than our own, suffered a sudden and violent collapse. Extremely high levels of gamma radiation from the star's core caused its energy to transform to matter, and the drop in energy in turn caused the star to collapse. This resulted in a dramatic increase in the thermonuclear reactions that was burning within it. All this added energy overpowered the gravitational attraction causing the star to explode.

And explode it did.

Scientists claim that the supernova was over 150 times more powerful than any other observed to date. Physical models suggested that such a supernova was theoretically possible, but astronomers believed that such events were limited to the early Universe when stars tended to be hypergiant.

A hypernova like SN 2006gy can instantly expel about 10X46 joules. This is more energy than our sun produces over a period of 10 billion years.

According to the Astroprof blog,
At discovery, it was already as bright as a Type Ia supernova at its peak. But, instead of getting dimmer, SN 2006gy continued to get brighter for several weeks. The peak brightness seldom comes much more than a week after the explosion. Theoretical models suggest that SN 2006gy gets its light from both the expanding cloud of gas and a shock front as the cloud of gas expands into very dense gasses surrounding the progenitor star. But, the expanding gas cloud is so bright that it requires substantially more radioactive decay to heat it that would be present in almost any other supernova. The best way to get that much radioactive material, according to the model that the theorists have come up with, is for basically the whole core to be thrown out into the supernova, leaving little or nothing behind to form a neutron star or black hole. So much material is thrown out, that the supernova continues to be heated long after the explosion itself. In fact, even months later, SN 2006gy has faded in brightness only to as bright as the peak brightness of a Type Ia supernova!
In fact, astronomers were able to observe the hypernova's peak brightness for an astounding 70 days.

Supernovas can wreak tremendous havoc in its local area, effectively sterilizing the region. These explosions produce highly collimated beams of hard gamma rays that extend outward from the exploding star. Any unfortunate life-bearing planet that should come into contact with those beams would suffer a mass extinction (if not total extinction depending on its proximity to the supernova). Gamma rays would eat up the ozone layer and indirectly cause the onset of an ice age due to the prevalence of NO2 molecules.

Supernovas can shoot out directed beams of gamma rays to a distance of 100 light years, while hypernovas and gamma ray bursts can impact areas as far as 500 light years away.

Thankfully, hypergiant Eta Carinae, which is on the verge of going nova, is well over 7,500 light years away from Earth. We'll be safe when it goes off, but you'll be able to read by its light at night-time.