It is indeed a fallacy, when it is used in place of argument to justify it.
The “fallacy” part arises because it elides the necessity for making argument to justify the assumptions used for the “slope” A to B to C (etc.). The longer the “slope” asserted without justification, the more fallacious it is.
The weak point is the “inevitability” of the slide: arguing that the change from point A to point B is bad, because it will lead to point C, is a “fallacy” where no actual convincing evidence is presented that moving from point A to B will, in fact, “inevitably” lead to C.
Calling it out as a fallacy is indistinguishable from saying “present convincing evidence that A to B will, in fact, inevitably lead to C”. Supporting it as not a fallacy is indistinguishable from providing that evidence.
In short, given that the burden is always on the person making an assertion to prove it, there is nothing wrong with calling out a slippery slope fallacy: it is the same as saying your argument does not have the evidence you need to prove your point.
I don’t see why this too doesn’t apply to any other form of argument.
But beyond that, ISTM that the Slippery Slope argument is generally used as a rationale rather than an attempt to prove things. Meaning “we have to oppose any attempt to back off Position A, because if we retreat to Position B we’ll inevitably end up at Position C”. In this context there is no such thing as the “burden of proof”.
To take the example in the OP, suppose someone couldn’t prove that letting Hitler annex the Sudetenland would likely lead to a wide-scale invasion of Europe, but couldn’t provide evidence that this would happen - it was just an assessment. Are you saying that this could not be used as a rationale to take a firm stand on the annexation?
Or perhaps you have some example of the Slippery Slope being used a proof of something?
Of course it’s a fallacy—an informal fallacy. The fallacy consists in assuming some item A is logically indistinguishable from some other item Z—such that if A then Z—when they are not logically indistinguishable. It’s an informal fallacy because it is not a fallacy of form (a violation of the conditions for validity) but a mistake about the extralogical relationship between A and Z (i.e., a mistake about how to characterize the world, not logical form).
“Slippery slope fallacy” simply refers to cases in which the alleged relationship between A and Z is not established, because one is simply incorrect about something in the world. If one is correct, then there is no fallacy. It does not say that every chain of conditional statements is fallacious. That would be silly.
So in sum, it’s no different than any other type of argument which could be valid or invalid in a given instance but which doesn’t get “fallacy” attached to it.
ISTM that the term “slippery slope fallacy” is frequently used to give additional cache to an argument that ultimately boils down to a subjective disagreement. “That’s a Slippery Slope Fallacy” sounds a lot better than “I disagree with that assessment”, even if the first ultimately boils down to nothing more than the second.
It’s an Informal Fallacy, which means generally the only reason for not using it is in a High School debate.
Like many Informal Fallacies, it’s not a Logical fallacy at all. They just call it that.
Of course, if the "slope’ is outrageous then everyone will understand a comment like “That’s some far our slipper slope there”, but it does not invalidate the argument.
As with practically anything else having to do with actual or so-called logical/rhetorical fallacies, RationalWiki (which specializes in this sort of thing) has a page covering almost every conceivable aspect of the topic, including:
Yes, any form of argument that relies on assertion rather than evidence is subject to attack.
Your problem with this is … ?
What you appear to be saying is that there is nothing wrong with making assertions. There isn’t, but assertions don’t usually win arguments: evidence and reason based on evidence does.
Some things become obvious in hindsight. That doesn’t mean that arguments as to why such and such was “inevitable” aren’t bad arguments: the fact that something actually happened does not make its happening “inevitable”.
It is amusing in the extreme that, in attempting to counter the validity of the slippery slope informal fallacy, you rely heavily on yet another informal fallacy:
Now, there were plenty of perfectly good arguments as to why Hitler had to be stopped (like “despite what the bastard says, if you actually read his nasty book, you will see that annexing the Sudetenland will never satisfy him”). However, like that one, they rely on evidence. Simply asserting that his rampage was inevitable, without evidence, is just so much hot air.
No, what I was saying is that Slippery Slope arguments are generally not offered in an attempt to “win arguments”. Rather, as a rationale for a course of action.
Therefore, the fact that such assertions don’t usually “win arguments” is not relevant. The point of the argument is just to offer a rationale for supporting or opposing a course of action. The listener may or may not agree with that rationale, but pointing to its existance adds something to the contemplation of the issue.
See above.
I didn’t offer the Hitler analogy as an example of a valid slippery slope argument (which would rely on it having been correct), but rather as an example of a typical form of the argument. Which is, again, as a rationale for a course of action, rather than an attempt to prove anything or win an argument.
Meaning, a guy in the 30s making that argument was not trying to prove that Hitler needs to be stopped. He was offering a reason that Hitler needs to be stopped.
Seems to me a distinction without a difference. A “rationale for a course of action” = “an attempt to convince others” = “an argument”.
Your “rationale for a course of action” isn’t convincing to others who are thoughtful unless it is backed by “facts” and “reasoned argument”.
Unless what you are really saying is that it is a good rhetorical technique to use to convince others to a course of action who are not reasoned and thoughtful - that is, an informal fallacy.
That’s not so. Some things just boil down to subjective judgement. Another person’s subjective judgement might be the same as yours. Or not.
If you’re a guy in the 30s discussing the plusses and minuses of taking a firm stand on the Sudetenland, it would be a mistake to just completely leave out the possibility that this will lead to a slippery slope just because you can’t prove it. It’s a big part of the issue.
Perhaps the other guy, when you raise this issue, will agree with you and think that tilts the scales in favor of intervening. Perhaps he won’t. But either way, it’s properly a part of the discussion, regardless of whether you can use it to “win the argument” or prove that you’re right.
I don’t get it. Whether or not to go to war with Germany (which is what this amounted to) is surely a subject on which reasoned, logical analysis ought to be valued; not something to just do because some guy thinks it’s cool.
Do you take the same attitude towards modern wars?
Back when I would read books about interpersonal psychology and influence one tactic that came up was the fact that if you got someone to agree to a minor commitment, then you could get them to agree to a more major commitment later. I don’t know if it was cognitive dissonance or what, but it came up more than once.
It isn’t a real fallacy, but drawing the line between fallacy and valid is hard.
And those who dismiss legitimate fears to give an inch take a mile types as engaging in slippery slope fallacies are probably aware of that tactic. It’s clever actually.
Interesting parallel. Perhaps it’s the same part of the brain working. Just as people can fall for, or make, a slippery slope fallacy, they can tie themselves up into a slippery slope line of thought/emotion and fall for the sales pitch.
That’s a psychological explanation for the mechanism of a particular “slippery slope”.
If one gives an explanation for a slippery slope, one isn’t engaged in an informal fallacy (though of course, one could then debate the validity of that explanation, back and forth).
The point about the slippery slope being an informal fallacy is that it is an “argument” that disguises the lack of explanation for exactly how one gets from A to B to [undesirable] C. It’s a sort of argument by assertion.
For example:
“If you agree to allowing Germany take the Sudetanland, you will inevitably agree to allowing Germany to take Poland and then Russia” - slippery slope informal fallacy: no mechanism or explanation is provided as to why this would inevitably follow aside from mere assumption and assertion.
“If you agree to allowing Germany take the Sudetanland, you will inevitably agree to allowing Germany to take Poland and then Russia, because psychologically, having caved once, it will become habitual, and you will be unable to resist further demands; these studies demonstrate this effect” - no slippery slope informal fallacy; a mechanism is proposed for why A to B will lead to C (which then can be debated).
