[BurningFrog]

"You never know" is an argument usually applied selectively. It has the advantage that it is always true.

Yeah, we don't know what terrible unforeseen consequence letting this species go will have.

But we don't know what good consequence it might have either.

[lisper]

We can make some pretty good guesses. We make this kind of judgement call about species all the time. Like it or not, we pick the winners and losers in this world. That's why there are lots of dogs, cows, and chickens, and no smallpox viruses (at least not in the wild). It's because we've decided that dogs, cows and chickens deserve to live because they make our lives better, and smallpox viruses don't deserve to live because they make our lives worse.

It seems to me that a Sumatran Rhino is a lot more like a dog or a cow or a chicken than it is like a smallpox virus. It's true that we can't eat them or keep them as pets, but just the ability to go see one in the wild has value IMHO.

[BurningFrog]

> just the ability to go see one in the wild has value IMHO.

Two thoughts:

1. A common mistake is to think that just because something has value, it's good to do. This reasoning ignores cost! Only by comparing cost and benefits can we make informed choices.

2. This value is specific to you. Others assign less or more value for this.

[lisper]

True. But...

3. Causing a species to go extinct eliminates all possibility of anyone extracting any value from it now or in the future. That has an unknown and potentially enormous cost in the long run.