The culture’s killing implements abruptly appeared in the archeological record and disappeared just as fast, after the easily killable megafauna went extinct. Today’s North American megafauna are , not North American megafauna that learned to avoid humans. Bison are the only significant exception, although they came from Asia, too, and explaining their survival remains a minor curiosity, but is about the only circumstance not neatly aligned with the overkill scenario. The “” paper concluded that although the South American extinction was the greatest of all, it is the most poorly investigated and that the overkill hypothesis cannot yet be attached to South American extinctions. That may be a prudent position for a specialist who pronounces judgment only when all the evidence is in, but I will be among the most surprised people on Earth if the pattern of 50 thousand years did not continue there, especially since it had no ice sheets. There can be no more pertinent example than comparing Africa to South America. They inhabited the same latitudes and have similar climates, separated by the Atlantic Ocean. Africa was the home of humanity, where its animals had millions of years to adapt to the human presence, and Africa only lost about 10% of its megafauna (probably to human hunters with their advanced weaponry) while South America lost nearly all of its megafauna, and quickly. Climate change did it? How could it have even contributed?
The methods of preindustrial civilizations, with deforestation and agriculture, were never really sustainable, as they disrupted ecosystems and even affected local climates. The only way that the system, for instance, was sustainable was that they let the land go fallow for eight years after two years of crops, in order to let the damage heal before farmers repeated the cycle. Only when practices were intermittent, to allow ecosystems to recover somewhat, could they be called sustainable, but even then the idea is somewhat misleading. It was an ecosystem commandeered for human benefit at the expense of the original ecosystem’s denizens, and the practice never approached true abundance. Those civilizations were all mired in scarcity, with only about one person in a thousand living to a ripe old age, and only about “making it” economically (the potentate). In such a world of scarcity, life was often cheap, and virtually every preindustrial civilization had , from to to chattel slavery to becoming a human sacrifice to other forms.
A series of critical reflection economic an hypothesis
Just as the aftermath of the appearance of complex life was uninteresting from a , as the amazingly diverse energy-generation strategies of archaea and bacteria were almost totally abandoned in favor of aerobic respiration, biological solutions to the problems that complex life presented were greatest during the Cambrian Explosion, and everything transpiring since then has been relatively insignificant. Animals would never see that level of innovation again. While investigating those eonic changes, many scientists have realized that the dynamics of those times might have been quite different from today’s, as once again may be of limited use for explaining what happened. Also, scientists generally use a rule-of-thumb called , or parsimony, which states that with all else being equal, simpler theories are preferred. , a seminal theorist regarding the scientific method, as they were easier to falsify. However, this issue presents many problems, and in recent times, theories of or speciation have invoked numerous interacting dynamics. Einstein noted that the more elegant and impressive the math used to support a theory, the less likely the theory depicted reality. Occam’s Razor has also become an unfortunate dogma in various circles, particularly , in which the of materialism and establishment science are defended, and often quite irrationally. Simplicity and complexity have been seesawing over the course of scientific history as fundamental principles. The recent trend toward multidisciplinary syntheses has been generally making hypotheses more complex and difficult to test, although and ever-increasing and more precise data makes the task more feasible than ever, at least situations in which are not interfering.