There you are, sitting in a lifeboat, saltwater stretching out to the horizon in every direction.
There are others in the boat, and, besides them, people clinging to the gunwales; and, further away, other people thrashing in the water and calling for help. There are other lifeboats in the near distance.
Your boat was stocked with rations, and it is possible to obtain food by fishing, and to replenish your drinking water by catching rain or operating a manual pump. But obviously, there are limits to how many souls your lifeboat can accommodate.
Arguments about who should be allowed in the boat are based on various premises: a posted weight limit, the traditional notion that women and children have priority, perhaps some duty stemming from maritime law. Quarrels erupt over the meaning or application of these rules. Wealth is regarded as conferring authority, although money is of no practical use here. Stronger occupants threaten to exert their power in decision-making.
Which of those outside the boat should be saved? Relatives of those already aboard? Those with useful attributes, such as nautical experience or the ability to fish, or a willingness to work? Some claim that religion or skin color are good indicators. Are people to be turned away because they were previously aboard another boat that broke apart? Some say that, because we cannot save everyone, we have no choice but to row away from the others.
If usefulness is the criterion, doesn’t it make sense that those already aboard should be judged on their own contributions? Are the laggards, or the disabled, or the elderly, say, to be cast adrift?
The air is chilly, and many assert that it will be necessary to burn the hull, bit by bit, for warmth. That barely-audible voice, the one saying, “Shouldn’t you at least try putting on a sweater first?” well, that’s me, the environmentalist. Because in our analogy, of course, there is no rescue vessel, there is no dry land. There are only lifeboats.