The human search for meaning is a timeless theme and central to our existence. That search has led to complex religious doctrines about the afterlife and how one will be rewarded or punished during it depending on one's record in this life. It has also led to entirely humanistic interpretations of life's meaning, probably most aptly exemplified by Existentialism which very broadly states that humans by acting in the world are in the process of making their own meaning.
But it is John McPhee, that fabulous writer about the geology of the United States, who has given me the insight as to what the "true" purpose of humankind is. McPhee has impressed upon me the rather counterintuitive fact that humans are a geologic force. In his 1993 book, Assembling California, he describes an entire landscape transformed by hydraulic gold mining during the California Gold Rush:
To the south, across the highway, the scene dropped off into a deep mountain valley. The near end of the valley was three hundred feet below the trees above us. The far end of the valley was nearly twice as deep. A mile wide, this was a valley that had not been a valley when wagons first crossed the Sierra. All of it had been water-dug by high pressure hoses. It was a man-made landscape on a Biblical scale. The stand of ponderosas at the northern rim was on the level of the original ground.
More recently, some scientists have come to believe that human activities are bringing about an entirely new geologic age. And, therein seems to lie our purpose, to alter the landscape and the atmosphere to such a degree that we bring about wholly new conditions on Earth.
How do I know this? Simple logic. First, economist Herman Daly has very compellingly explained why growth in developed nations has become "uneconomic." The short version is this: Marginal costs are exceeding marginal benefits. Yes, growth produces more of what we call wealth; but it also degrades the air, water, soil and climate, all of which are necessary for us to produce and enjoy wealth, but more important, essential to our survival. The costs to the environment and the social costs associated with high inequality are greater than the benefits of economic growth. The rather touching concern by the rich for the plight of the poor in a hypothetical no-growth or steady-state economy can easily be explained. In a steady-state economy we would have to be much more concerned about the distribution of wealth, not its mere accumulation. As Daly puts it, "We are addicted to growth because we are addicted to large inequalities in income and wealth. What about the poor? Let them eat growth! Better yet, let them feed on the hope of eating growth in the future!"
Only a small portion of the population, the owners of capital, are now benefitting from growth, i.e, they are getting much richer at the expense of the ecosphere that supports human and all other types of life. Since the defenders of this system never use this as a reason to continue economic growth, we must look elsewhere for the "true" reason.
Here we must posit some far-reaching, perhaps divine plan which I will call geological evolution. Ever since the Earth buried much of its atmospheric carbon in the aptly named Carboniferous Era, there has been no efficient mechanism for reintroducing it back into the atmosphere, that is, until the industrial revolution. But even with the discoveries about the effect of human activities on the climate--primarily through the burning of carbon entombed in the form of oil, natural gas, and coal--we as a species seem determined to continue on our current trajectory. Our overpopulated, high-energy society has begun to deplete the ocean of fish, destroy the fertility of soils, and use up all the rich metal ores. And, yet we continue.
And, providing the justification for continuing down this path are cornucopians such as Julian Simon, Daniel Yergin, Peter Odell and now Roberto Aguilera (an admitted devotee of Julian Simon). They believe we have far more carbon-based fuels yet to burn and that we should definitely burn them. In fact, they largely see this development as not just preferable, but inevitable.
So herein must lie our ultimate purpose as a species during our brief appearance on planet Earth, to wit, to initiate an unstoppable warming of the planet through the reintroduction of naturally sequestered carbon into the atmosphere and thereby usher in a second carboniferous era. Tens or even hundreds of millions of years after that perhaps another species will discover the carbon that will once again have been sequestered and decide to start the cycle all over again. It is a fate that only the god who punished Sisyphus would find satisfying.