"We should treat one another as the priceless beings we appear to be, and care for our rare cosmic home, the Earth."

Howard A. Smith writes at cosmosnautil.us.com, about the role of earthly humans in our universe.

...From a purely scientific perspective, recent books and papers have shown that that it takes much more than a hospitable environment for life even to arise, much less to evolve and survive to become intelligent. At a minimum, it takes billions of years of relatively stable conditions. Any putative planet must at least be in a stable orbital system around a star that is neither short-lived nor an emitter of toxic X-rays. Numerous evolutionary biologists, writing on the remarkably contingent nature of the evolution of humanity, have added a biological caution: Even on the Earth, if evolution were repeated, it is not likely to produce intelligent beings again. Thus, even though the processes at work around the universe are more-or-less similar, some events are less likely than others to occur. Until we know more, we must acknowledge that the evolution of intelligent life could be the result of an astronomically unlikely sequence of events.

Astronomers using NASA’s Kepler telescope and other facilities have found over 3,000 exoplanets so far, and even determined many of their sizes and masses. The discoveries have been a remarkable achievement, but no surprise to my colleagues or me. After all, we expected them. What was surprising is that we also expected them to resemble the solar system, but many don’t. In fact, the single most remarkable discovery about exoplanets is their exotic variety. Among the new planets are some Earth-sized ones in their “habitable zones” (the habitable zone is the range of distances from the star where water, thought to be essential for life, can remain liquid). Even more exciting, the statistics so far imply there could be a lot of them. But Earth-sized by no means Earth-like. Venus and Mars are Earth-sized and in the habitable zone. Moreover, most of the currently known Earth-sized exoplanets orbit around stars that are neither like the sun nor particularly hospitable. The nearby star Proxima Centauri is one such example. Its active winds and X-ray radiation probably inhibit life from forming on its recently discovered, nearly Earth-sized planet that orbits it every 11.2 days.

All the observations so far are consistent with the idea that humanity might not be common. Moreover, we are unlikely to find out one way or the other for millennia, so this conclusion will remain a distinct possibility for a long time. I call this the Misanthropic Principle.

...That the universe appears to be fantastically finely tuned for intelligent life is not particularly controversial, and is the second piece of evidence related to the end of Copernican Mediocrity. But, you might ask, why is the universe so perfect?

I am an experimental scientist because I love discovering the world and its often surprising, unexpected, features. I think it is good advice not to make too many assumptions, and presuming we must be commonplace is an assumption. Of course, presuming we are rare is another. Instead, we must learn from nature with an open mind. I think the evidence, and the simplest conclusion, is that humanity is not ordinary and we may have a significant cosmic role. There are, therefore, ethical issues to consider, and religion can contribute a meaningful voice to this discussion. We should treat one another as the priceless beings we appear to be, and care for our rare cosmic home, the Earth. Modern science may have prompted this re‐evaluation, but addressing it will require the best of all our human abilities.

Read more here.