Razib at Gene Expression provides an efficient capsule summary of the Christmas festival’s pagan lineage:

First, the cultural and historical origins of Christmas are multi-textured. Though Christians assert “Jesus is the reason for the season,” a more precise formulation might be that “Jesus became the reason for the season in the minds of some.” This is important. It is not without rationale that Christian groups like the Jehovah Witnesses reject Christmas, it is not a scriptural festival. Its emergence in the 4th century coincided with the synthesis of Christianity with Roman Imperial culture as the latter took upon the former as the state religion. In 274 the Roman Emperor Aurelian dedicated a temple to the sun god, Sol Invictus, on the 25th of December, Natalis Sol Invictus, “the birth of the invincible sun.” Interestingly, many early depictions of Jesus Christ co-opted solar imagery (e.g., the halo around the Christ). It seems that the thrusting forward of December 25th as the birth of Christ was strongly motivated by co-option of a pre-existing festival. Additionally, holiday merry-making seems to have its classical antecedants in Saturnalia. But this tendency of a mid-winter festival is not limited to Southern Europe. Yule and its cousins play an even greater role in the north than they do in the sunny Mediterranean. The darkness of the mid-winter solstice festivals bloom to usher in the season of hope and lengthening days. Customs like the Yule Log, Christmas cookies and gift exchange all emerge out of this pre-Christian substratum. This is was not unknown to the Christian Church, during the medieval period there were futile attempts to suppress some of these practices. A great enough frustration broke out during the Reformation that groups like the Puritans banned the celebration of Christmas, which was after all a minor holiday next to Easter.

Today the Christmas season has become capitalism’s handmaid. And yet nevertheless there is an economic case against Christmas. But such arguments will, I suspect, be as successful as Christian attempts to co-opt or abolish a fundamentally primal holiday. So long as winter’s darkness passes over us in the Northern Hemisphere our minds will demand a luxury to usher in the new year. It may not be economically optimal, but the human psychology naturally introduces inefficiencies and ‘irrationality’ into the action of Homo economicus. And so in some ways the battle between those who would “defend” Christmas, and those who promote a more inclusive Holidays, is somewhat beside the point, the name is less than the substance that persists. The tendency toward mid-winter holiday is, I believe, evoked from the natural interaction of our cognitive machinery and the seasonal flux of the world around us. The emergence and perpetuation of mid-winter festivals in agricultural societies in the north isn’t a coincidence or an act of cultural diffusion, it is a tendency which our minds are canalized toward. I believe that in general it is best to make the best of our eternal instincts in this matter. Our nature does not insist that we engage in a gross orgy of consumption after all, but neither can we truly honor the Puritan intent to root all acts in scriptural reason, or the economically optimal behavior which would deny the darkening skies above which finally cede ground to the sun. In the end, such exuberant “inefficiencies” are the ends toward which efficient means aim….

god bless us, everyone