Here we are, profoundly amazed to find ourselves on a planet speeding 67 thousand miles per hour through vast regions of cold space, impossibly removed from any other known place of refuge. And what a thin shell is Earth’s air supply! The highest human settlement—La Rinconada in Peru—is a little over three miles above sea level, meaning that, if the eight-thousand-mile-wide Earth were an apple, its skin would be thicker than its habitable atmosphere. Yet we are here, living our lives, usually too busy to consider such things, perhaps even thinking life is normal. And notice I just mentioned “thinking,” as if it were, in the cosmic context, quite commonplace. Honestly, the idea that the chemicals that compose us could be so organized as to “think” is astounding! And we are doing so on what is essentially a large rock, tucked beneath a veil of clouds, so close to the edge of life’s limit.The question of life’s existence has been the subject of speculation for time immemorial, and more explanations than we will ever know have been offered, all with great conviction. As is usual when questioning how things …