Facebook posts about prehistoric archeology

Lately, I've heard of several people who are fascinated by some Facebook posts related to what might have happened on Earth before recorded history.

Our knowledge of prehistory is intrinsically indirect, because we don't have contemporaneous accounts. We can only *infer* what happened using a careful analysis of the (often circumstantial) evidence we do have. This kind of analysis sometimes requires deep expertise to *do* but also to understand. (For example, I recently read a discussion of the supposed lengths of the reigns of kings in Sumaria that argued that the numbers were actually intended as a lesson in quadratic equations rather than an attempt to offer a realistic chronology. I had trouble following the details.)

The stuff posted on Facebook about what "really" happened before recorded history often only mentions the "evidence" that supports a particular viewpoint. It also often ignores any scholarly analysis that might contradict the intended inference. (For example, a piece about the Easter Island statues makes it seem like it's *new* that we've learned through excavation that the "heads" actually have bodies that go many meters under the ground. It's *not* new. Plus, there are very natural explanations of how the statues were buried over time.)

An analogy I want to make is to discussions about climate change. Many scientists have concluded from the evidence (*not* actual thermometers from 1000s of years ago!) that recent warming is unprecedented in the past 100,000 years. This case is pretty solid; few reputable scientists say these data and conclusions aren't pretty reliable. (Not perfect, but very good.) And yet many climate-change skeptics argue that we don't really *know* much about temperatures on earth before about 1800.

This is very much like those Facebook posts that say we don't *know* that the Earth *wasn't* visited by gods or extraterrestrials who seeded human civilization. 

In a very limited way, the posts are right that we don't *know*. We weren't there, and neither was anyone who wrote anything down. (The cave paintings are also subject to many different interpretations.)

But direct personal experience isn't the only way to *know* anything. In trials, for example, where evidence is often circumstantial, jurors are instructed to *use their common sense* in drawing reasonable inferences.

Similarly, I think we have to use our common sense in responding to Facebook posts about prehistoric archeology. Do we have *any* actual evidence that gods or extraterrestrials have ever visited the Earth? Do we notice gods or extraterrestrials interfering in today's world? Do we wonder whether it was possible to get to the moon or build the Chunnel without divine intervention?

But wouldn't it be *totally cool* if we discovered that aliens taught early humans mathematics or philosophy or how to move enormous stones? Sure! But the possibility of something that might be *totally cool* isn't reason to think it might be true.

Occam's Razor tells us the simplest explanation for an observation is most likely to be true. What is the *simplest explanation* of those supposedly lengthy reigns of kings chronicled in ancient Sumerian tablets? Isn't it more likely that the numbers were made up as part of propaganda by people working for other rulers thousands of years later to justify their current boss's rule? Or that the tablets were intended to provide a lesson in quadratic equations in a society worried about losing that almost sacred knowledge?

You decide. ☺️