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When the Slippery Slope is not so Slippery

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Original Question

"If assault weapons are banned, it will lead quickly to a ban on all guns." This is the quintessential example of the Slippery Slope fallacy, where the NRA lives. One of the most common of all logical fallacies. But what if the slope is not slippery, but predictable? "If the Republican Senate considers a tax cut for workers, the final bill will have all kinds of tax cuts for corporations and investors". OR, "If the Democratic House considers a small change to a provision of the ACA, the final bill will include coverage for things like viagra and plastic surgery." If you can predict with high probability that a proposed action will indeed lead to expanded results, is it a logical fallacy, or is it just predicting unintended consequences?

Answers

2

As I understand it, a fallacy may be correct, but as a modus logicam fails nonetheless.


A slippery slope may truly be slippery.  Defending the opposing contention (in this case, "no, it won't") by so naming it (here, the "yes, it is" contention)  fallacious  is merely deflecting.


Many governmental ukases were supported as benign at their outset.  The historical record suggests cautious acceptance of Trojan horses.


In plain language, 2A was not to "permit" self-protection against robbers, or "permit" hunting in the king's forest. It simply recognized the right we all have, and was included as a warning to a potential overweening government that the citizens were citizens, not subjects.  Subjects may be given permissions; citizens own them by right of birth and acceptance of allegiance.

Like all informal fallacies, what is or is not a Slippery Slope is arguable. There are examples that are clearly fallacious, those that are clearly not fallacious, and those that lie in between. The Slippery Slope fallacy has two general criteria used in this assessment:



  1. What is the probability of each outcome?

  2. How many outcomes from the first action to the last claimed outcome?


The higher the probabilities and the fewer stated outcomes, the more likely it is to be legit and not fallacious. Take for example:


If people panic, they will buy up all the toilet paper. So don't panic.


Not fallacious. One outcome and the outcome is extremely likely.


If people panic, they will buy up all the toilet paper. If there is no toilet paper left, people will get violent. So don't panic.


A little questionable, but not wholly fallacious.


If people panic, they will buy up all the toilet paper. If there is no toilet paper left, people will get violent. If people get violent, billions of people will be murdered. So don't panic.


Okay, now are well into fallacy land.


 

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