Have you ever heard a sentence that doesn’t make sense, but you can’t prove it to be wrong? And that the only thing you can say to the sentence is that it’s nonsense? If you have never heard of such sentences, take a look at the concept of Last Thursdayism.
The concept of Last Thursdayism proposes that everything in existence got created last Thursday. The universe, yourself, and the Pyramid of Giza came into existence only last Thursday. God or the Big Bang created everything last Thursday. Of course, we know that this is not true, but how do we prove that Last Thursdayism is wrong? Sure, the simplest way is to take a look at your birth certificate. However, Last Thursdayism will say that it is merely a birthdate and that the birth certificate was created last Thursday. How about the remnants of world war 2? Yes, it was also created last Thursday.
Of course, we all know that Last Thursdayism is nonsense. However, disproving Last Thursdayism is the real challenge here. We call propositions such as Last Thursdayism as unfalsifiable. It means that though we can’t prove it to be true, we also can’t prove it to be false. But how do we prove anything at all?
According to discrete maths, or the study of logic, one of the ways to prove something to be true is to prove the opposite of the statement to be false. For example, to prove the sentence “I do not have two dogs” to be true, you need to prove the statement “I have two dogs” to be false. The method of proving the opposite statement to be false is “Proof by Contrapositive”. We do this when it is much easier to disprove the contraction than it is to prove the original statement. There are actually many more ways to prove statements such as “Proof by Contradiction”, “Direct Proof”, etc. You can read more about proving statements here.
Proving statements is easy when it is verifiable in one way or the other. However, Last Thursdayism is not verifiable because we cannot put a label on anything that ever happened in history. Sure we can use dates, but dates can technically be made up or forged. All of this results in Last Thursdayism to be virtually impossible to prove or disprove, and thus its unfalsifiability.
Introduction to the razors
Back when the scientific method was in its infancy, there was no way to check the verifiability of many propositions or statements. Therefore, there were many propositions which are unfalsifiable and unprovable in society. To deal with this, philosophers need to find a way to get to the truth through bypassing the verifiability check that proofs need to have. Finally, they came up with the concept of razors, which is a principle that will cut out most statements that are unfalsifiable or have unlikely explanations. To understand more about razors, we need to take a look at some of their examples.
Occam’s razor is probably one of the most famous razors in philosophy. When provided with several propositions, this razor proposes to choose the statement with the simplest explanation and fewest assumptions. Simply put, the best solution is the simplest solution. Occam’s razor will cut out Last Thursdayism since it requires a lot of assumption. It is much more difficult to assume that the Great Wall of China suddenly popped into existence Last Thursday than it is to follow its history.
Hitchen’s razor proposes that if a proposition was brought to light without evidence, then it can also be dismissed without evidence. It places the burden on the person proposing the statement to find the evidence that will back them up. Hitchen’s razor will also dismiss Last Thursdayism as it has no significant evidence to back it up. Moreover, this is the razor that you might want to keep in your pocket to guide your daily life. Having this razor in your arsenal ensures that your arguments will be sound and based on concrete evidence.
Newton’s Flaming Laser Sword
If you haven’t guessed from its name, this is the strongest out of all the razors in philosophy. It is so strong that it is not named a razor. Although Newton’s flaming laser sword might be a little bit too strong for most propositions, it is also undoubtedly the coolest of them all (hence the featured image of the article). Newton’s flaming laser sword proposes that anything that cannot be settled by experiments is not worthy of a debate. Therefore, there is no doubt that this razor, or sword, cuts through Last Thursdayism with ease. However, using this in your daily life will be too impractical. After all, we can’t scientifically experiment with everything.
There are many other razors in philosophy with their own principle on how to deal with uncertain explanations or unfalsifiability. Knowing them, in general, can definitely help you discern logical propositions and illogical propositions. Who knows, one day you might be faced with a statement that is not as obviously misleading such as Last Thursdayism. In those times, pulling out one of philosophy’s razors from your arsenal will be an immense help.
Vsauce talks more about Last Thursdayism and philosophical razors in this video:
So, was everything created last Thursday? Get one of your razors and find out for yourself.
Featured Image by Moonpointer