More Jeff

 Jeff McMahan answers critics in a new post on the NY Times:

opinionator.blogs.nytimes.com/2010/09/28/predators-a-response/

AMong his considerations are these thoughts on the extinction of the Siberian tiger:

"If their number in the wild declines from several hundred to zero, the impact of their disappearance on the ecology of the region will be almost negligible. Suppose, however, that we could repopulate their former wide-ranging habitat with as many Siberian tigers as there were during the period in which they flourished in their greatest numbers, and that that population could be sustained indefinitely. That would mean that herbivorous animals in the extensive repopulated area would again, and for the indefinite future, live in fear and that an incalculable number would die in terror and agony while being devoured by a tiger. In a case such as this, we may actually face the kind of dilemma I called attention to in my article, in which there is a conflict between the value of preserving existing species and the value of preventing suffering and early death for an enormously large number of animals."

How many herbivores does he suppose a Siberian tiger kills in the course of a year? And how does he know that they "live in fear" and "die in terror and agony"? (See my last post on the topic for my thoughts on that.)

I post all this here rather than in comments to McMahan's posts so that they don't get lost among the hundreds.

He also reemphasizes his qualifications in the original column that of COURSE he understands the dangers of herbivorous population explosions in the absence of predators, and that he had made EXTENSIVE QUALIFICATIONS of his remarks, that they would ONLY apply if and when the (peaceful and gentle) extinctions of predators could be accomplished without unwanted consequences.

To which I replied:

"We should also engage in carefully controlled and subtly thought-out wars to remove harmful and counterproductive governments that harm their citizens and threaten the world -- but ONLY IF we can be absolutely certain that no one would be harmed by such a venture and that all consequences of our action would be benign. It is absurd to posit hypotheticals such as that. What can be learned by contemplating impossibilities?"