As I see it, there are two main schools of Cosmist thought, which I like to call “Light Cosmism” and “Dark Cosmism” (aka "Cosmicism"). To better understand these schools, I offer the stirring words of four great cosmic thinkers who capture the spirit of each side: Carl Sagan and Marshall Savage vs. H.P. Lovecraft and Friedrich Nietzsche:
“The surface of the Earth is the shore of the cosmic ocean. From it we have learned most of what we know. Recently, we have waded a little out to sea, enough to dampen our toes or, at most, wet our ankles. The water seems inviting. The ocean calls.” –Carl Sagan, Cosmos
“We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age." –H.P Lovecraft, The Call of Cthulhu
“The size and age of the Cosmos are beyond ordinary human understanding. Lost somewhere between immensity and eternity is our tiny planetary home, the Earth. In a cosmic perspective, most human concerns seem insignificant, even petty. And yet our species is young and curious and brave and shows much promise. In the last few millennia we have made the most astonishing and unexpected discoveries about the Cosmos and our place within it, explorations that are exhilarating to consider. They remind us that humans have evolved to wonder, that understanding is a joy, that knowledge is prerequisite to survival. I believe our future depends powerfully on how well we understand this Cosmos in which we float like a mote of dust in the morning sky.” –Carl Sagan, Cosmos
“In some remote corner of the universe, poured out and glittering in innumerable solar systems, there once was a star on which clever animals invented knowledge. That was the highest and most mendacious minute of "world history" — yet only a minute. After nature had drawn a few breaths the star grew cold, and the clever animals had to die. One might invent such a fable and still not have illustrated sufficiently how wretched, how shadowy and flighty, how aimless and arbitrary, the human intellect appears in nature. There have been eternities when it did not exist; and when it is done for again, nothing will have happened.” –Friedrich Nietzsche, On Truth and Lie in an Extra-Moral Sense
“The human race will disappear. Other races will appear and disappear in turn. The sky will become icy and void, pierced by the feeble light of half-dead stars. Which will also disappear. Everything will disappear. And what human beings do is just as free of sense as the free motion of elementary particles. Good, evil, morality, feelings? Pure ‘Victorian fictions’. Only egotism exists.” –H. P. Lovecraft
“Teetering here on the fulcrum of destiny stands our own bemused species. The future of the universe hinges on what we do next. If we take up the sacred fire, and stride forth into space as the torchbearers of Life, this universe will be aborning. If we carry the green fire-brand from star to star, and ignite around each a conflagration of vitality, we can trigger a Universal metamorphosis. Because of us, the barren dusts of a million billion worlds will coil up into the pulsing magic forms of animate matter. Because of us, landscapes of radiation blasted waste, will be miraculously transmuted: Slag will become soil, grass will sprout, flowers will bloom, and forests will spring up in once sterile places. Ice, hard as iron, will melt and trickle into pools where starfish, anemones, and seashells dwell — a whole frozen universe will thaw and transmogrify, from howling desolation to blossoming paradise. Dust into Life; the very alchemy of God.” –Marshall Savage, The Millennial Project
So there you have the two Cosmist schools in a nutshell: The universe is a black sea of infinity in which science is suicide, life is futile and only egotism exists, or it's an inviting cosmic ocean where science is the key to boundless life and progress. I find them both incredibly poetic and compelling, and have difficulty choosing sides. What say you?