A few final musings, on themes that have shown up on this blog, especially with regard to why history matters and how it relates to science. Historical Accidents. There is a school of thought that dismisses history as a mere collection of facts and dates, and doing history as postage stamp collecting; this contrasts with Science, which is about discovering universal Natural Laws. There’s nothing wrong at all with looking for universal laws, but it has sometimes led to people ignoring the role of historical contingency. For example, paleontologists for a long time were reluctant to believe that a cosmic accident had destroyed the dinosaurs. Biogeographers downplayed the role of wildly unlikely accidents – a few monkeys rafting across the Atlantic to South America – in creating modern animal distributions. Some of the most dramatic demonstrations of the role of accident in creating our world are from even earlier. We’ve known for decades now that our Moon comes from the collision of a Mars-sized body with a young Earth, with the debris from that collision coalescing to form a satellite. A priori, this particular sequence of events was wildly unlikely. And just this year (and too late to blog about at the time), we’ve been given reason to think that the early history of the Solar System was even more extreme. It looks like there may have been an early generation of “super-Earths,” bigger than earth but smaller than Neptune, in the inner solar system. Then Jupiter and Saturn did a gravitational dance – a “Grand Tack” – into the inner system and back out, that sent these early planets colliding with one another. Most of the debris of the collision fell into the Sun. A fraction coalesced to form the inner planets, resulting in a most atypical solar system. And going all the way back to the beginning: the great dream of physics, a Theory of Everything that explains the universe, may now be collapsing. Our best current theories of physics involve some version of string theory. But the equations of string theory have many solutions – 10^500 is a number often bandied about – and it may be just blind luck that we live in a universe governed by one particular set of solutions rather than another. Other universes in the Multiverse may be governed by other solutions, many inhospitable to life. The laws of physics of our universe, like the genome of our species, may incorporate a large dose of historical accident. Putting History Back into Prehistory. For some decades, a lot of Anglo-American archeology has shied away from doing culture history, from reconstructing the formation of ethnic groups or (even worse) the migration of peoples. The focus was supposed to be on universal principles of social evolution and ecology. To get a feeling for what this involved, imagine reading a history of eastern North America from 1450 to 1850 that is chock-a-block with facts and figures on village and town layouts, subsistence regimes, trade, and technology, but doesn’t bother to tell you that the country was invaded and resettled by outsiders. This view of the past has recently been upended by recent work in human genetics, which has demonstrated a recurring role for population movements and full or partial population replacements. This work in many ways hearkens back to the time when archeologists worked closely with historical linguists. We’ve found ourselves covering a lot of this work on Logarithmic History. We’ve also given a special place to innovative work using oral history and mythology to push back the reconstruction of the past. (All this inspires a question: James Turner’s recent book Philology: The Forgotten Origin of the Humanities demonstrates just how central this discipline was to the establishment of the modern humanities. Is it time for a revival of philology in the humanities?) Historical Science. If scientists have sometimes been tempted to downplay the role of historical contingency in shaping the world, historians (I mean historian historians, not Big History types) have often been tempted to downplay the search for scientific laws of history. But I think there has been promising work lately in this area, borrowing from theories of multi-level selection in evolutionary biology to understand the rise and fall of states and civilizations. I’ve also allowed my own specialty, the anthropology of kinship, to put in an appearance here. All of this is intellectually exciting (I hope). But it also makes for some somber reflections, on matters ranging from “nature red in tooth and claw” and mass extinctions in the evolution of life, to ideological meta-ethnic frontiers and mass killing in the history of the twentieth century.