Someone will point out that a proposed measure could lead to more similar measures and then, someone else will dismiss that saying “It is a Slippery Slope”.
My question is: do slippery slopes exist? It is my understanding that slippery slopes DO exist, but since almost everything can be spinned to look like one, such arguments do not have much value.
The “slippery slope” is the rhetorical technique of testing a general principle by pointing out its most extreme or controversial consequences or examples, ie. a kind of Reductio ad Absurdans.
This might lead to the general principle being modified or discarded altogether. In many cases the principle under discussion is not actually stated explicitly.
Whether the slope “exists” depends on what the principle at stake is, and whether the examples can be said to be reasonable or fair manifestations of it.
If we’re going to start giving up on types of arguments because they can be spun, we may as well give up on language altogether.
Curse you for beating me to the joke! While you’re at it, why don’t you just torture me to death and then tapdance on my grave?
Daniel
From a not-so-serious angle on this let’s examine the Baseball Hall of Fame.
It is common among the baseball (not so) intelligensia (i.e. sportswriters who need to fill column inches every day) to make the argument for a players inclusion in the Hall with the argument that ‘Player X is the only person with Stat Y not to be in the Hall of Fame’ or ‘Player X has the most stat Y of any player not in the Hall of Fame’.
This leads to some craziness come election time. Where does it stop.
Say Player X has 500 HR and gets in.
Then Player Y with 490 is the ‘most without being in’ and the argument gets him in.
Then Player Z with 480 etc…
Now I realize that logical argument is not exactly one of the strong points of sports writing in general…but it’s clearly an example of the slippery slope in action.
So why is the slippey slope considered as a logical fallacy?
It isn’t, unless either the general principle or its consequences are misrepresented.
Most commonly it is fallacious when it is argued that the slope is so slippery, we wouldn’t be able to stop once we get on it; in other words arguing that the (undesirable) end consequence and possibly some (undesirable) steps along the way are an inevitable result of the first step.
Example: If we permit same-sex marriage, we will next have to allow paedophilia; eventually it will be legal for a man to marry a dog.
Can you give an example of when a slippery slope argument can be used in a non-fallacious way?
I think St Paul had it right. He preferred celibacy but grudgingly accepted heterosexual marriage. next thing you know, Bob’s your Uncle, and we have gay marriage. 
I think that Mangetout has the key to slippery slopes here. There’s nothing wrong with them, they are rhetorically powerful, and they certainly should be considered when taking a course of action. Ignoring a trend, which is all a slippery slope “really” is, is foolish behavior. But those that use it should also be aware that what seperates a slippery slope from a logical deduction is the necessity of the end result. Gun control leading to a gun ban is a slippery slope: we should be vary wary of the end result every step of the way (if we want guns), but we should also be aware that a restriction on any particular firearm does not compell a restriction on all firearms, necessarily.
I really don’t want to turn this thread into yet another gun control debate, but using gun control as a test to falsify the slippery slope hypothesis may not be the best example. After all, there does exist a not insubstantial number of gun control advocates, including several federal legislators (and many, many more at the state and local levels), who have made public pronouncements that total gun bans are their eventual goal and that they are consciously engaged in a plan to chip away at gun rights one piece at a time. There are people who admit they’re attempting to place the United States, and/or other, smaller governmental divisions, on just such a slippery slope.
Now whether this meets mangetout’s test of inevitability (which certainly seems a reasonble test to me) can be argued. After all, no matter how loudly the gun banners shout, and no matter what tactics and strategy they employ, it is simply very unlikely that a total gun ban will be enacted in the United States anytime soon. But the political climate is, of course, subject to change, and at some (now unforeseeable) point in the future, the political climate could certainly swing in a direction where this might be possible. So, while, as I said there’s room to argue the inevitability of such a measure, there are not a few people advocating using just such tactics and strategy to further their ends; thus, the slippery slope exists, not just in the minds of gun rights activists, but also in the minds of the gun control activists.
So as Uncle Beer illustrates, when is “slippery slope” not a rhetorical fallacy?
When it suits my rhetorical purposes, of course! 
I don’t believe that was his intention, DSeid. And I would agree with him: chipping away at a foundation is much easier than a straight attack. This has been done with the abortion issue, as well; instead of the previous times’ efforts to remove the entire ruling, a time of fanatics making headlines for murder, the effort has toned down considerably and fighting on various fronts that seem minor but collectively work towards the same end. Whether this is strictly a conscious effort, or simple selection-by-success (each success encourages more nibbles on the abortion front), I don’t know.
I think that kind of argument is wishy washy in the first place… you want to make a case? Make a case that player X has BETTER stat Y than comparable people already in the hall!! (AND better than other players outside the hall too, of course.)
A non-fallacious, because factually true, example of a slippery-slope argument:
Jingoistic paranoiacs of the 1950s were successful in getting our national motto changed to “In God We Trust.” So now jingoistic paranoiacs of the present day use that fact to support their active attempts to tear down the constitutionally mandated separation of church and state.
The “slippery slope” metaphor is just an exaggerated form of the “foot in the door” metaphor.
How does one distinguish a slippery slope from a change in our culture? A ban on guns could be the bottom of an unintended slippery slope, or it could be a reflection of the ever changing desires of the population.
Personally, I don’t think a slippery slope can give a result too far different than what the populace in general wants, i.e. it’s not really all that slippery.
Well, sometimes there are actual feedback loops at work. It can be difficult to see these when you’re dealing with cultural matters, but try adjusting your car seat front-to-back while stepping on the brake at the same time. The laws of physics will ensure that you suffer a slippery slope catastrophe.
Legislative changes do not follow the physical laws governing bodies in motion. The slppery slope model presumes gravity, inertia, and lack of resistance. In politics, if you stop pushing, no further movement in that direction will take place. More significantly, there’s the phenomena of the backlash–movement in a partiular direction can provoke a counter-movement that is often stronger. for example, far from placing us on a slippery slope to “socialism”, Clinton’s health care plan provoked a massive anti-governement movement in the mid-90’s.
Backlashes can provoke their own backlashes and in the end, the “pendulum” model is a bit closer to reality.
Cornell University has a nice hilly side, facing the lake, that is called “The Slope”.
So yes, a slippery slope does exist in Ithaca, NY, after a rain shower or in winter