Mars was empty before we came. That’s not to say that nothing had ever happened. The planet had accreted, melted, roiled and cooled, leaving a surface scarred by enormous geological features: craters, canyons, volcanoes. But all of that happened in mineral unconsciousness, and unobserved. There were no witnesses – except for us, looking from the planet next door, and that only in the last moment of its long history. We are all the consciousness that Mars has ever had.
Kim Stanley Robinson [Red Mars, 1993]