In my experience, the arguer is rarely if ever able to provide the missing support for their argument, though; that’s why the assumption that they don’t have any such support is the default. This is especially true if they actually use the term ‘slippery slope’; the notion of a downward slope is generally a really poor analogy for most real causal effects - and thus not what you’d hear used in place of an actual known cause.
The arguer who tried to skip steps is always welcome to fill in the holes, though.
To put in another example, you’re claiming that a reference to a “slippery slope” should be an acceptable debate tactic because it substitutes for known arguments.
Imagine if I went in to the “Define God” thread and said “Belief in God is a slippery slope to the corruption of human morality”. Now, I may even be able to defend that (sort of, and certainly there are people who would defend it on this board), but making a blanket assertion and waving to a generic “slippery slope” of evidence is a fallacy of debate, since I have made a logically valid conclusion, but have done nothing to prove my point.
Same with gun control. Here’s a slightly longer example.
(NOTE: The evidence I use in the first part is completely false and is used for illustration purposes only)
Gun registration is a bad idea, because it leads to Gun confiscation. In 1998 Tom, Dick, and Harry did a study (cite), that showed in 12 nations that began to register guns within a few years of 1978s, 10 of them went on within 10 years to place stricter controls on who could own guns and what types of guns could be used. in 7 of those countries, gun crimes did not decrease, and in fact 2 showed an increase in gun crimes in that time. Of those 10, within another 10 years (by 1998) 5 of those had begun programs of wide-spread gun confiscation, with one notable country, Acirema, indeed completely banning gun ownership in any non-governmental capacity entirely within 12 years. Thus, research shows that gun registration is the first step in to a path that leads a majority of countries to begin major restrictions to gun ownership.
Compared to: Gun Registration starts a slippery slope to Gun Confiscation.
Both are LOGICALLY equivalent, in that they create a logical connection between Registration laws and Gun Confiscation, but the first argument provides a full argument, where the second commits the fallacy of slippery slope (very bluntly, to get the point across, the same effect could be achieved by “Gun Registration laws mean within 15 years we’ll be losing all of our guns to the government!”) because it ASSUMES and doesn’t try to prove the middle of the argument, instead “handwaving” at the facts, whether or not they are there, because the average person wouldn’t immediately know all of the facts that you just glossed over.
I don’t really disagree with any of that. It’s obvious that the sample paragraph is more convincing than the assertion of a slippery slope. My only bone of contention is that the less convincing sentence should therefore be termed fallacious. Again, I think the central idea is that slippery slope is actually referring to an existing social science reality. If that is so, not making it explicit is probably a poor rhetorical choice and can absolutely be accused of not being persuasive. But a fallacy? The example would be me saying something like “the Phillips curve suggests that this unemployment policy will lead to higher inflation” instead of “this unemployment policy will likely lead to higher inflation because of the historical relationship between inflation and unemployment. This relationship blah blah blah…”
Actually, the second ‘argument’ is merely a single assertion: Premise: A will lead to B, full stop. It is a statement that offers nothing to persuade the audience of its truth, and isn’t really an argument at all, logical or otherwise. The audience is left to arbitrarily decide whether or not to believe the statement based on things unrelated to the truth of the matter, such as the charisma of the speaker and the scariness of the conclusion.
That’s most of what makes it an informal fallacy: it’s a tactic to persuade that draws its persuasive power from illogical or incorrect sources. The other thing that makes it an informal fallacy is that this particular form of invalid argument has been perpetrated often enough to earn itself a unique name.
You really seem hung up on the word ‘fallacy’ here. To put it succinctly, informal fallacies are nothing like logical fallacies. Ignore the fact that they share a word for a moment. A logical fallacy is a specific logical mistake inside a specific logical argument. An informal fallacy refers to a specific type of bad rhetorical debating technique. One is primarily for formal proofs, the other primarily for informal debates and arguments. See the difference?
Oh, and I wouldn’t call “the Phillips curve suggests that this unemployment policy will lead to higher inflation” a slippery slope, I don’t think. It cites a source: this Phillips curve thing. That’s a piece of evidence. An argument sporting the slippery slope fallacy does not cite evidence; it’s a scare tactic. The first thing mentioned is an action that the arguer wants prevented. The end result is something that he knows his audience wants to avoid. The statement is that allowing the first action will cause the second action, one way or another. Here are some examples:
“This unemployment policy will lead to higher inflation”
“If we legalize marijuana then soon our kids will have access to all kinds of drugs”
“Gun Registration starts a slippery slope to Gun Confiscation”
“Legalizing gay marriage will bring about the death of the american family”
“Listening to rock music will turn your kids into satanists.”
“Violent video games will make your kids more violent”
See? Scary stuff, better not let it happen! As I mentioned aboive what makes it a fallacy is that it relies on the emotional response, rather than the facts. If you cite a source, then you don’t really qualify.
(If your source is crap or doesn’t say what you claim, you have other problems of course. But you’re not committing the slippery slope fallacy.)