Philosopher's Deduction Fallacy
The Philosopher's Deduction Fallacy is the name of I've given to the problem with philosophers. If anyone wonders why the ravings of philosophers seem so pointless and irrational, it is due almost entirely to this single fallacy. The fallacy is the belief that knowledge cannot be certain unless it is derived exclusively from deduction.
The word 'prove' has two meanings. The first meaning is to derive from the rules of logic. This is the meaning that philosopher's tend to utilize, ignoring almost entirely the second meaning. The second meaning is to show evidence of. If little Jimmy and Freddy are playing one day, and Jimmy tells Freddy that he can run faster than him, Freddy will say "Prove it!". It would be surprising if Jimmy showed a mathematical formula, or other such deductive method. Instead, he races Freddy.
Philosophers, on the other hand, go through elaborate mental acrobatics to try to convince you that the world before you is real. Often, they give it up as impossible, and then wrongly conclude that the world isn't real. Or more likely, they say that "We can't be sure if the world around us is real". Why? Because they accept the idea that to really know something for sure, it needs to be a product of deduction.
The first question, of course, is what knowledge they are using to deduce. Deduction requires some initial knowledge. We say that Socrates is a man, and all men are mortal. We then deduce that Socrates is mortal. But where do we get the knowledge that Socrates is a man? Or that all men are mortal? Sometimes you can step farther back and derive one of those statements with deduction as well. But eventually, there needs to be knowledge that isn't gained deductively.
This is the crux of the problem for philosophers. Only induction can give them the roots they need to deduce. Induction, though, is considered unreliable, since it is not "provable". So philosophers talk about A Priori Knowledge. The most important piece of a priori knowledge they insist on is the rules of logic. In order for one to use deduction, one must have knowledge of the rules of logic. How does one gain knowledge of it? The answer is through induction. So they have to come up with methods of pretending that the rules of logic are not dependent on induction. Which means it is not dependent on perception. Which means it is not dependent on reality.
The games continue, but because they cannot accept induction, they have to create a philosophical system that does not depend on it. Which means that it does not depend on reality. And the result is that it does not correspond to reality either. Although the loop is bigger than normal, the result is an attempt to use circular reasoning. And the result is useless, pointless nonsense.