Back To CourseBasics of Astronomy
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JFK, 9/11, the moon landing, the Bermuda Triangle, and a ton of other stuff have something very much in common. They all have competing conspiracy theories trying to explain what happened and why. Multiple shooters, inside jobs, Hollywood fakes, and UFO abductions, just to name a few.
Conspiracy theories are faulty, not only because they completely disregard factual evidence proving them false but also because of a principle we'll be delineating in this lesson. If conspiracy theorists only followed this simple principle, they wouldn't waste their time on their convoluted and overly complex (not to mention unprovable) explanations of what, oftentimes, has already been explained. This principle is known as Occam's razor.
William of Ockham, also spelled with two 'c's' instead of a 'k,' was a Franciscan philosopher who was born in 1285. He was famous for what I just mentioned, Occam's razor. This is a philosophical principle that, in its original form, states, 'Plurality should not be posited without necessity.' That definition is one reason why I don't like reading most historical philosophical writing, or at the least, their translations. They make things sound more complicated than they need to be.
Since simple explanations of the same thing are better than complex ones, let me put Occam's razor for you another way. In simple person speak, Occam's razor says that when there are two competing theories that make the same predictions or reach the same conclusion, the simple theory is better. Or, to put it in an even simpler way, the simplest explanation of some sort of observation in nature is the one that is most likely to be correct. That's the principle of Occam's razor. The reason the word razor is used is because we use this principle to shave away extraneous details from an explanation for something.
Conspiracy theories aside, let us look into a couple examples of Occam's razor to help further explain this concept: one example from normal life and one related to science. Let's say that you came home one day and found that the stove was on. This surprises you since you're normally very diligent about not forgetting to turn it off. One explanation for this is that you left it on after cooking earlier and simply had a brain lapse, even if you don't want to admit to it.
Another explanation may be that someone broke into your home while you were gone and turned the stove on, so it's not your fault the stove is on. The second explanation means someone had to know how to pick your door lock, disarm your alarm system, avoid detection by neighbors, clean up any evidence of entry such as fingerprints, turn the stove on, and leave just as quietly without being detected. Not to mention, you have to come up with some sort of motivation for this intruder to do such a thing.
The first explanation only requires a brain lapse and a lack of action on your part to turn the stove off. Therefore, in the absence of any evidence to the contrary, the first explanation is the simplest and the one that is most likely to be correct.
From a scientific standpoint we can apply the same principle to explanations of retrograde motion of the planets. This is the apparent backwards motion of a planet against the background of stars. Imagine you're on a circular racetrack, riding in a really fast car. You know that everyone on the racetrack is moving forwards in the same direction. But since you are going really fast, as you overtake slower cars, they appear to move backwards, away from you. Clearly, they are not doing this, but because you are moving faster than they are, it seems to be so.
Keep this in mind, for some, but not all, ancient astronomers and philosophers believed for a variety of reasons that the Earth was in the middle of our solar system and the then-known universe. Yet, such a model could not explain retrograde motion of the planets very well. We now know that each planet takes a different time to complete its orbit around the sun. Faster moving planets, like Earth, will overtake Mars every now and then, making it seem that Mars is moving backwards.
Well, geocentrism, the idea that the Earth is at the center of the universe, does not lend a helping hand in explaining retrograde motion of the planets. Some ancient astronomers that believed in this defunct theory used very complex models of circles revolving around other circles in different ways to try and explain this retrograde motion. It was so complex, it was scary, not to mention very wrong!
To put it mildly, such theories would require the cars on the racetrack to not only circle around the main loop they are all on, but also simultaneously circle around in their own individual little racetrack loop as they do so!
As soon as astronomers accepted the fact that the sun is in the center of our solar system, it became really easy to explain retrograde motion, as I already have via planetary orbits and their speed. Retrograde motion, be it of Mars or of a car you are passing, is nothing more than an illusion! Two theories, trying to explain the same thing, and the simpler theory won. Once again, Occam's razor proved its worth.
William of Ockham, also spelled with two 'c's,' was a Franciscan philosopher for whom the principle of Occam's razor is named. His principle states that, 'Plurality should not be posited without necessity.' Simply put, the simplest explanation of some sort of observation in nature is the one that is most likely to be correct. Occam's razor can be applied to two once-competing theories for the explanation of retrograde motion of the planets. This is the apparent backwards motion of a planet against the background of stars.
Geocentrism, the idea that Earth is at the center of the universe, forces the explainer to come up with very convoluted explanations of why retrograde motion occurs with complex circles upon circles moving every which way! But as soon as you realize the fact that the planets revolve around the sun, it becomes easy to explain retrograde motion by simply understanding that planets move at different speeds and when one passes the other, like a car on a highway, it appears that the slower planet is moving backwards. Retrograde motion is, therefore, an illusion.
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Back To CourseBasics of Astronomy
28 chapters | 325 lessons