Restricting consideration only to the qualification “best for the Earth,” where that means something like best for the well being of current eco-systems and current non-human populations, I think the answer is yes, it would be better if we all dropped dead, especially if “this rate” of destruction remains unchanged. But, of course, what is best for the current eco-systems and current populations must be weighed against other considerations such as what is “best for” certain projects and cultural formations we also rightly value—human communities, nations, literary, scientific, spiritual, and artistic projects. It is true, indeed, that those will disappear along with the rest of life on the planet if ecological destruction continues beyond the point at which human life or those projects can be sustained. It’s not clear, however, that the current rate of destruction will persist or that we will reach that point. It is not clear that it won’t or that we won’t, either. There seems to be a reasonable...

This is a fascinating question, in some ways, I think, it's connected to the question of whether we have responsibilities to things bigger than us in the sense of things that can continue to exist without us--e.g. things like families, nations, political and artistic movements, cultures, universities, businesses. Generally, I would say there is a moral obligation to sustain good things generally--at least where sustaining some good thing doesn't require undermining another of greater value. To your specific question: I would say that considering the species itself, there is no obligation to sustain it, since the simple existence of the species is neither good nor bad, so long as there are other species to substitute for it. Considering the species as part of the larger ecosystems of the planet, where genetic diversity is salutary for the health of living things generally, there is an obligation insofar as the well being of living things is good. Considering the existence of the species as the...

For the most part, I agree with you that there's a lot of confusion out there about the notion of intrinsic value. As I see it, value can only occur through a valuer or group of valuers. No valuers, no value. The idea that value exists independently of valuers is incoherent. Having said that, I don't think that the concept of "intrinsic value" to be utterly worthless or non-sensical. It's a useful concept for contrasting against "instrumental value" or "commercial value." Hence "intrinsic value" may be used meaningfully to describe what you point to in your question under the rubric of "existence value"--value accorded the natural world as not used, even when it's not used, or because it's not used. But I also think it epxresses a kind of value humans recognize that isn't well expressed through economic categories like "willingness to pay" or "price" or "market value." Translating values, costs, and benefits into monetary figures is notoriously difficult, and I think for good reason. So, it's...