The Nature of Knowledge.

If you’re like most people, you probably haven’t thought about Pompeii since the week you learned about it in your 5th grade history class. As 17th century archaeologists sifted through the ancient remains of the city that had been buried under feet of volcanic ash by the famed Mount Vesuvius, we were able to learn a great deal about the culture, the artwork, the craftsmanship, the architecture, and the ancient civilization that once thrived in southern Italy. I can recall from my childhood history textbook the images of the bodies of humans and animals, fleeing and cowering for their lives, mummified and immortalized in volcanic ash.

But for some reason, elementary school spent an inordinate amount of time on this very brief event and one of the most important lessons to be learned from the discovery of Pompeii was completely neglected.

Herculaneum once thrived in the shadow of Mount Vesuvius before being buried in 79 AD.

For over a century, it was believed that the civilization of Pompeii was the only victim of the violent eruption of Mount Vesuvius. However, while excavating for a summer palace for the King of Naples in 1738, workers discovered the remains of a second city that had been buried and wiped from the face of the earth. Herculaneum, as the city came to be known, contained many intact buildings and paintings and papyrus scrolls that had been preserved in ash.

In the 5th grade history lesson on Mount Vesuvius and Pompeii, we learned nothing about Herculaneum. It took about a decade and a half for me to learn the truth about that historical event — that a second city had been utterly destroyed along with Pompeii. However, the lesson that was glossed over in elementary history class was not the tale of two cities (Pompeii and Herculaneum) buried by a violent volcanic eruption, but rather the changing nature of “knowledge” itself.

In August of 2006, one of the nine planets of our solar system was no longer classified as a planet — instead, it was demoted to “dwarf planet.” For centuries, Pluto had been classified as a planet. It came as a shock to many that something so widely “known” and accepted could change at a moment’s notice. Perhaps the criteria for “planethood” is a bit arbitrary, but it raises an important point: What we consider to be “knowledge” is not absolute. Our knowledge is not necessarily the entire picture of reality. All scientific discoveries or classifications can be subject to change in the event that new evidence becomes available. Just as history was rewritten to include Herculaneum, so too were our science textbooks edited to accommodate Pluto’s new classification.

In fact, there have been many, many times during the course of human history in which we were forced to revise our worldview as new information became available to us.

Until about 330 BC, it was believed that the earth was flat. Based on our best evidence (mainly our limited perspective), it seemed that the earth was flat. It was even considered common “knowledge” that the earth was flat. Around 350 BC, however, the ancient greek philosopher Aristotle made several key observations that provided the evidence necessary to overturn the prevailing flat-earth belief. First, Aristotle noticed that as you travel north or south, the stars you see in the sky change location. This would only be possible if the observer was traveling along a curved surface. Next, Aristotle noticed that as ships sailed away at sea, the bottom of the ship would disappear first as it was sailing towards the horizon. The very top of the mast would be the last portion of the ship to disappear. In this case, the ship is literally sailing over the curve of the earth. Lastly, the shadow of the earth on the moon during a lunar eclipse is always circular. The only shape that always has a circular shadow is a sphere. Forgetting about the hundreds of photos of Earth we now have thanks to our much more recent endeavers in space exploration, this evidence is enough to prove the earth is round. These simple observations of the physical world contain all the evidence necessary to change humanity’s ideas regarding the shape of the earth. The fact that flat-earth theory is making a resurgence in the year 2016 and 2017 is an indictment of the American educational system and a testament to our unwillingness to let go of ideas that became intellectually irrelevant millennia ago.

Also during the time of Aristotle, it was believed that dolphins and whales were fish. However, Aristotle knew better. Based on his observations and dissections, Aristotle understood that these animals were more closely related to humans than they were to fish. Unfortunately, as a minority in this belief, his discovery could not unseat the widespread belief that these sea dwelling creatures were fish. Aristotle didn’t simply believe without evidence that his claims were true. Through a scientific scrutiny of these mammals, Aristotle learned that, unlike fish, they did not have gills. They had to return to the surface periodically to breathe. He knew through the dissection of beached specimens that they did indeed have lungs. He may have also understood that they gave birth to live young rather than laying eggs as fish do. There are a number of pieces of evidence that could have been observed by Aristotle that may have led him to this realization, but his lone idea failed to overcome the common belief that was held by a majority of the people. Fortunately, this is an error that has since been corrected. For the years in between, Aristotle’s knowledge was lost and the growth of scientific knowledge — and even society — was stunted.

Similarly, until Nicolaus Copernicus’ and Galileo Galilei’s observations regarding the phases of the moon and the moons of Jupiter in the 1500s, it was believed that the heavenly bodies revolved around the earth. Significant new evidence was presented and, after great resistance from the Catholic Church, the geocentric model of the solar system gave way to truth.

All of this is not to say that there can be no certainty in our knowledge, or that the truth is relative to what we currently have cause to believe. However, if we can ever hope to have an accurate understanding of reality, we must afford our models and our ideas a certain fluidity to change as new information becomes available. The best we can hope for is a persistent and constant revision of our body of knowledge as new evidence becomes available. Much like the Theory of Evolution (another unpopular discovery for which the burden of proof has been thoroughly satisfied), the ideas and knowledge that result from the systematic study of the world around us are the result of a sort of self-purification. In the Theory of Evolution, the organisms that are least fit for survival are done away with and those that are most fit contribute to the future of the species. Likewise, the ideas that fail to stand up to future scientific scrutiny cease to persist in the scientific realm. It is through this constant process of scrutiny and revision that we can claim to know anything at all. Though the ideas we come up with may not be exactly representative of reality, there will always be an approach being made (perhaps asymptotically) to the truth.

A mistake regarding something like the number of cities claimed by a volcanic eruption doesn’t seem to be that important at first. However, we can’t claim to have a worldview based on reality if that worldview doesn’t shift — at least slightly — as new evidence comes to light. If we allow our science and our knowledge to stagnate, it won’t be long before the truth of reality itself is buried and forgotten, much like the ruins of Herculaneum.