Imagine a small crowd of people – a hundred or so – in a public place. A few minutes earlier they were all in transit to various other destinations, but a momentary spectacle has drawn them together. They do not, for the most part, know each other and in most cases they’ll never see each other again once they go their separate ways. They include representatives of every age group from infancy to dotage; there are people of various ethnic backgrounds, political and religious persuasions, socioeconomic status and states of mental and physical health. There is little consensus among them with respect to tastes or aspiration. Some are happier than others.
The people in this crowd have come to be together purely by accident, and it is the kind of accident that will never again draw this same crowd: the crowd has no identity, no “meaning.” Many people would be tempted to say of the people who make up that meaningless crowd, “They have nothing in common.”
But that sweeping statement, “They have nothing in common,” is not entirely true is it? They are all human, so they have that in common. Since they are all human, they are all the offspring of two biological parents, even if one of them merely traded his semen for cash at a sperm bank, or if in vitro fertilization was involved. And this makes it possible to list a great many other commonalities: they all have 23 pairs of chromosomes; they’re all bipeds; they’re all mammals; they’re all vertebrates; they’re all mortal; they’re all subject to the laws of physics and chemistry that make life possible, sets its limits, and so forth.