IT IS ODD that the national holiday set aside for the benign purpose of expressing gratitude should also celebrate a primal encounter between European settlers and the native peoples who preceded them.
In the American memory, Miles Standish, in his Pilgrim hat and broad collar, is forever shaking hands with Massasoit, who saved the settlement from hunger with instructions about growing corn and catching turkeys. It was 1621 when the settlers and the natives sat down together to celebrate ''good increase,'' and their harvest banquet became the paradigm of neighborliness, the good feelings we all indulge this week.
One needn't attribute base motives to those English separatists to acknowledge that their arrival was anything but an occasion for thanksgiving to those who greeted them. Indeed, the mythic encounter that took place at ''Plimouth'' was an instance, in a phrase of the historian Jared Diamond, of ''the greatest collision of modern history,'' the colonization of the New World by Europeans, which led to the effective disappearance of most groups of native peoples.
Less than 100 years before Standish and Massasoit met, a far more typical encounter took place well to the south when the Spanish conquistador Francisco Pizarro captured the Inca ruler Atahuallpa. The year was 1532, and that event, too, occurred in November. It was the true paradigm for what was coming because, despite collecting a massive ransom, Pizarro murdered his prisoner and conquered the Inca people.
In his book ''Guns, Germs, and Steel,'' Diamond asks why the outnumbered Europeans were so successful in overcoming the forces that greeted them. He finds answers in the military advantage of their horses, guns, and armor, but there was the even more decisive factor of ''diseases transmitted to peoples lacking immunity by invading peoples with considerable immunity.''
A smallpox epidemic had come to the Inca region ahead of Pizarro, and, indeed, smallpox would clear the way for European settlers again and again. The succumbing of native populations to ''germs'' throughout the New World is well known, but invader-borne disease was a key factor wherever European colonizers traveled, from South Africa to the islands of the Pacific.
In the eventual outcome, it did not matter whether the arriving Europeans came in a spirit of amity, as we like to think those Pilgrims did, or of conquistador bellicosity. Standish or Pizarro - all the same. Some colonizers were guilty of deliberate acts of genocide, while others were the passive beneficiaries of less violent mutations. From the point of view of those replaced, however, the newcomers' arrival itself was the destructive event.
The image that Graham Greene famously applied to ''The Quiet American'' - ''a dumb leper who has lost his bell, wandering the world, meaning no harm'' - is apt for colonizers of all kinds, whether they mean harm or not. The movement of populations and the intermingling of cultures are morally complex phenomena, although in memory they are made simple by the disappearance of the displaced persons and their lost cultures. Massasoit is remembered as happy because he is a character in the morality play written by the Pilgrims and their children. Massasoit's own story is untold this week.
The reason to acknowledge, against all mythology, that there has been a universally brutal underside to migration, often involving conquest and victimhood, always involving infection of some kind, is not to renounce the profoundly human impulses to move and settle. Rather, it is to invent an ethic of movement and settlement that is respectful and nonviolent toward those whom the newcomers encounter. Therefore, the main moral obligation settlers have upon arrival is to see their arrival from the point of view of the indigenous.
This is true on the local scale: Such a shift in seeing explains why a majority of Israelis oppose in principle most Israeli ''settlements'' in the disputed territories. And it is true on the global scale as well, since ''settlements'' today can involve the airways as much as land. Thus, an American-style beauty pageant, with its celebration of the female as sex object, can be yet another dumb leper wandering the world without a bell, meaning no harm. Media and entertainment entrepreneurs have an absolute obligation to anticipate - and mitigate - the culture-smashing effects of their interventions.
Thanksgiving is a simple feast, but the event it commemorates was complex. A profoundly American story, yet the tale of the encounter between the settlers and the natives has never had more human resonance. Can one culture meet another without destroying it? Can both cultures survive, celebrating a new mutuality of influence and exchange? Can the hope that was embodied in Massasoit's gift of corn and turkeys, and in European gratitude, be finally realized?