Literature is the original Internet – every footnote, every citation, every allusion is essentially a hyperlink to another text, to another mind. - Maria Popova

In the ancient Greek allegory, Theseus — the founder-king of Athens — sailed triumphantly back to the great city after slaying the mythic Minotaur on Crete. For a thousand years, his ship was maintained in the harbor of Athens as a living trophy and was sailed to Crete annually to reenact the victorious voyage. As time began to corrode the vessel, its components were replaced one by one — new planks, new oars, new sails — until no original part remained. Was it then, Plutarch asks, the same ship? There is no static, solid self. Throughout life, our habits, beliefs, and ideas evolve beyond recognition. Our physical and social environments change. Almost all of our cells are replaced. Yet we remain, to ourselves, “who” “we” “are.

Above all, Somerville possessed the defining mark of the great scientist and the great human being — the ability to hold one’s opinions with firm but unfisted fingers, remaining receptive to novel theories and willing to change one’s mind in light of new evidence.

Behind each door of what-if lies an unanswerable question that unhinges an infinite Rube Goldberg machine of probabilities. The life we have is the only one we will ever know, and even that with tenuous certainty.