Oil and Sand - The Hard and Fast Limits of Nature

The invention of steam was this early case of humans extracting energy to escape what had theretofore seemed like hard and fast limits set by nature. And that's a constant refrain in your, your book, all this exploitation and destruction of nature. But we're finding out that nature still has hard and fastlimits. We've just sort of deferred them, it's true. I mean, so oil and sand, i've actually written an article somewhere else about the oil and sand being these two incredibly significant commodities.