Understanding the Slippery Slope Fallacy

[Galteeth]

I wasn't sure where to put this, as it is a question pertaining to logic, but not mathematical logic per ce.

I don't understand why the slippery slope argument is considered a fallacy, especially in a political context.

While it is obviously incorrect to say that some action inevitably leads to a consequence by means of a slippery slope, it does not seem incorrect to say that it can make such a consequence more likely. Incrementalism (the idea that the public will not tolerate large, sweeping changes but that smaller, incremental changes can lead to the same result without as much opposition) is an idea that has historically been used by political leaders, such as Ceasar Augustus. I was thinking about this in the context of the senator who recently proposed the biometric ID card as part ofd the immigration reform bill. He basically said that the public was ready for this because in today's society we are constantly made to show ID. It seems that if such a rule was passed (this bill specifically creates a biometric ID card that would be required as verification of empolyment elligibility) it does in fact make anothe rule (such as hypothetically that such cards could be a requirment for voting) more likely.

This post is not about biometric ID, but about the notion of the slippery slope. It seems logical that in a case where a progressive series of changes have been tending in a general direction, but no individual change seems unreasonable given the current state of things, there becomes a necessity of "drawing the line" somewhere by pointing out the slippery slope.

I understand the difference between "inevitably leads to" and "makes more likely" but can someone explain why this is considered a logical fallacy?

 

[leroyjenkens]

Here's a quote from the wikipedia article that sounds like it answers your question.

The heart of the slippery slope fallacy lies in abusing the intuitively appreciable transitivity of implication, claiming that A lead to B, B leads to C, C leads to D and so on, until one finally claims that A leads to Z. While this is formally valid when the premises are taken as a given, each of those contingencies needs to be factually established before the relevant conclusion can be drawn. Slippery slope fallacies occur when this is not done — an argument that supports the relevant premises is not fallacious and thus isn't a slippery slope fallacy.

http://en.wikipedia.org/wiki/Slippery_slope

 

[Galteeth]

Here's a quote from the wikipedia article that sounds like it answers your question.

http://en.wikipedia.org/wiki/Slippery_slope

The wikipedia article confused me. It did not seem to make the distinction in there examples between "inevitably leads to" which is recognizable as incorrect, and "makes more likely."

The cited gun ownership example does not make sense to me. Each of those arguments seem like they are valid.

 

[Frame Dragger]

The wikipedia article confused me. It did not seem to make the distinction in there examples between "inevitably leads to" which is recognizable as incorrect, and "makes more likely."

The cited gun ownership example does not make sense to me. Each of those arguments seem like they are valid.

There are real slippery slope arguments that are not fallacious, it is when they are abused beyond reason that the fallacy emerges.

 

[BobG]

I think they're splitting hairs with the idea of a slippery slope fallacy. Different situations:

1) Even though this looks like a small change, it makes some other change inevitable, which makes another change inevitable, and so on. This is the slippery slope argument used correctly.

2) Technically, it's not the same as giving your opposition the one small change they need to get their foot in the door. (And the foot in the door concept is not a fallacy. If you get people to agree to one request, they are statistically more likely to agree to your next request.)

3) It's definitely not the same as the argument that once you've moved a small way towards some end point, the likelihood of reaching the endpoint is greater. This is a valid argument, just not technically the slippery slope argument. (This argument is valid in football, as well. Surprisingly, if a team has the ball close to their own goal line, their opponent is more likely to achieve the next score even though they don't yet have the ball.)

While many people do technically abuse the "slippery slope" argument, claiming a particular argument is a slippery slope fallacy is often a red herring. The person stating a particular change puts us on a slippery slope to X has made a mistatement even though their logic is valid for an entirely different reason (foot in the door syndrome, placing us in closer proximity, etc). The mistatement is trivial, but pointing out the mistaken terminology can derail the person from the point they were trying to make.

 

[Chi Meson]

One of the fallacious assumptions of the "slippery slope" is that the slope is slippery at all.

Each case needs to be appraised individually, but if a person or a society takes a step toward a condition that is considered to be "intolerable," then it is not correct to say that the next step will be easier. In some cases the next steps might be incrementally more difficult. It's sort of like "what if the "slope" is not downhill, but uphill?

This would be the case if steps are taken that move away from the current point of social equilibrium. The health care issue is an example. Any additional step toward social medicine in this country is virtually impossible right now, isn't it? If anything, the next step will be backward.

So one step toward a "condition" does not necessarily make arrival at that condition "more probable."

 

[Galteeth]

I think they're splitting hairs with the idea of a slippery slope fallacy. Different situations:

1) Even though this looks like a small change, it makes some other change inevitable, which makes another change inevitable, and so on. This is the slippery slope argument used correctly.

2) Technically, it's not the same as giving your opposition the one small change they need to get their foot in the door. (And the foot in the door concept is not a fallacy. If you get people to agree to one request, they are statistically more likely to agree to your next request.)

3) It's definitely not the same as the argument that once you've moved a small way towards some end point, the likelihood of reaching the endpoint is greater. This is a valid argument, just not technically the slippery slope argument. (This argument is valid in football, as well. Surprisingly, if a team has the ball close to their own goal line, their opponent is more likely to achieve the next score even though they don't yet have the ball.)

While many people do technically abuse the "slippery slope" argument, claiming a particular argument is a slippery slope fallacy is often a red herring. The person stating a particular change puts us on a slippery slope to X has made a mistatement even though their logic is valid for an entirely different reason (foot in the door syndrome, placing us in closer proximity, etc). The mistatement is trivial, but pointing out the mistaken terminology can derail the person from the point they were trying to make.

This clarifies matters, thanks.

 

[BobG]

One of the fallacious assumptions of the "slippery slope" is that the slope is slippery at all.

Each case needs to be appraised individually, but if a person or a society takes a step toward a condition that is considered to be "intolerable," then it is not correct to say that the next step will be easier. In some cases the next steps might be incrementally more difficult. It's sort of like "what if the "slope" is not downhill, but uphill?

This would be the case if steps are taken that move away from the current point of social equilibrium. The health care issue is an example. Any additional step toward social medicine in this country is virtually impossible right now, isn't it? If anything, the next step will be backward.

So one step toward a "condition" does not necessarily make arrival at that condition "more probable."

I think using "disrupting a stable equilibrium" argument or "disrupting an unstable equilibrium" argument provides more clarity than using the slippery slope argument.

Being specific about which equilibrium condition currently exists makes it a vector argument instead of a scalar argument. It avoids a person claiming a "slippery slope" condition exists when they really mean a "spinning your tires" condition exists.

Although, I have to admit that I've rarely, if ever, heard someone use a "slippery slope" argument to mean a stable equilibrium condition exists. But the equilibrium idea is still an appealling idea for aesthetic reasons, if nothing else.

 

[Galteeth]

One of the fallacious assumptions of the "slippery slope" is that the slope is slippery at all.

Each case needs to be appraised individually, but if a person or a society takes a step toward a condition that is considered to be "intolerable," then it is not correct to say that the next step will be easier. In some cases the next steps might be incrementally more difficult. It's sort of like "what if the "slope" is not downhill, but uphill?

This would be the case if steps are taken that move away from the current point of social equilibrium. The health care issue is an example. Any additional step toward social medicine in this country is virtually impossible right now, isn't it? If anything, the next step will be backward.

So one step toward a "condition" does not necessarily make arrival at that condition "more probable."

Yes, it does. The probability of a particular condition is still increased regardless of increasing difficulty of steps. To go with the football analogy, the last few yards towards the endzone may be the hardest to gain, but being on the five yard line makes a touchdown more probable then being on the fifty.

In the healthcare example, you are thinking of it as being the probability of another reform. You have to think of it as some hypothetical quantity of government involvement. When the HMO act was passed, for example, government becamed more involved in managing health care. The passage of this act made the total probability of arriving where we are today more likely.

EDIT: I missed your use of the word necessarily as a qualifier. Given that, your statement is true. There are always exceptions to general trends.

 

[Galteeth]

I think using "disrupting a stable equilibrium" argument or "disrupting an unstable equilibrium" argument provides more clarity than using the slippery slope argument.

Being specific about which equilibrium condition currently exists makes it a vector argument instead of a scalar argument. It avoids a person claiming a "slippery slope" condition exists when they really mean a "spinning your tires" condition exists.

Although, I have to admit that I've rarely, if ever, heard someone use a "slippery slope" argument to mean a stable equilibrium condition exists. But the equilibrium idea is still an appealling idea for aesthetic reasons, if nothing else.

Perhaps you could elaborate how these physical examples translate to real world arguments that are used correctly and incorrectly. I am interested in this subject, and think it is one of the more difficult subtleties of logic.

 

[Galteeth]

Another real life example: At the venue I work at it, we don't allow alcohol. But sometimes the owner will make an exception for an obviously older person. I always argue against this, because it has been my observation that allowing one person to drink will dramatically raise the probability of others drinking.

 

[Galteeth]

On a slightly tangenital note, it is interesting how arguments that are techinally fallacious are often true. There is that argument whose latin name I can't remmeber, the one where you basically say, well this person is an idiot so whatever they say is likley to be idiotic. Although this is not a valid argument against an individual point, it does generally hold true. For example, I don't know for a fact what the position of the reverend Fred Phelps of the "God hates fags" church is towards the flooding of Nashville. It is perhaps possible that he has a sound physical explanation for it. But I would bet everything I had that his explanation is that it was an act of God unleashed as punishment for toleration of homosexuality. I understand the difference between evaluating an individual argument versus the likelihood of future arguments. But it does seem that people who have fundamentally nonsensical world views will produce non-sensical arguments.

 

[BobG]

Perhaps you could elaborate how these physical examples translate to real world arguments that are used correctly and incorrectly. I am interested in this subject, and think it is one of the more difficult subtleties of logic.

Nudging a geosynchronous satellite out a gravity valley at 105 deg W longitude does not increase the probability of the satellite settling in the gravity valley on the opposite side of the Earth at 75 deg E longitude.

Any nudging of the satellite from it's stable equilibrium point results in forces that send the satellite back towards its stable equilibrium point. At most, the range of variability has been extended just a bit.

And while it's true that by nudging the satellite out of the gravity well, it will take less energy to permanently displace that satellite from the gravity valley, the amount of energy required to do it means the satellite will never settle into the opposite valley. The opposite valley is an impossible destination... in a single shot, anyway - it would take at least two separate phases: disrupt the current equilibrium; then conciously maneuver the satellite so that it would settle into the opposite equilibrium point.

Socially or politically, this would be equivalent to tearing a law or policy down, clearing the way for a new law or policy to be created from scratch to fill the vacuum. Tearing down the old merely creates opportunity for new - it doesn't give any particular new any advantage.

On the other hand, nudging a satellite off of a gravity bulge at 11.5 deg W longitude will result in the satellite drifting all the way to the opposite bulge at 162 deg E longitude, at which point it would only take a tiny nudge to balance the satellite over the opposite bulge.

 

[leroyjenkens]

Yes, it does. The probability of a particular condition is still increased regardless of increasing difficulty of steps. To go with the football analogy, the last few yards towards the endzone may be the hardest to gain, but being on the five yard line makes a touchdown more probable then being on the fifty.

You could say the same for fieldgoals. But I've seen teams purposely lose some yards because they were too close and the kicker was better a little farther back.

Like if you want to read a sign and you're too far away. Getting closer to the sign increases your chance of being able to read it, but if you walk up to it and stick your face right on the sign, you probably won't be able to read it.

 

[BobG]

You could say the same for fieldgoals. But I've seen teams purposely lose some yards because they were too close and the kicker was better a little farther back.

Like if you want to read a sign and you're too far away. Getting closer to the sign increases your chance of being able to read it, but if you walk up to it and stick your face right on the sign, you probably won't be able to read it.

And then there's the fallacy of using examples a lot more interesting than your main point. The reader goes off on a tangent, which is almost always a bad sine ... unless you're talking about small angle tangents and sines, of course. :rofl:

 

[Ygggdrasil]

I often find the slippery slope argument used to create a strawman argument. That is, people use the slippery slope argument to equate a small change with the most extreme change in the same direction and then argue against the extreme case instead of the real proposed changes. For example, proposals that do anything to increase government oversight of the economy are often equated with communism and met with arguments why communism is bad (but not necessarily why the specific proposal is bad).

3) It's definitely not the same as the argument that once you've moved a small way towards some end point, the likelihood of reaching the endpoint is greater. This is a valid argument, just not technically the slippery slope argument. (This argument is valid in football, as well. Surprisingly, if a team has the ball close to their own goal line, their opponent is more likely to achieve the next score even though they don't yet have the ball.)

This argument, however, is fallacious if you mischaracterize the endpoint. For example, consider proposals that desire to make America based more strongly on Christian values (e.g. restrictions on abortion). One could argue that such proposals would increase the probability of America becoming a fundamentalist theocracy (e.g. like a Christian version of Iran), but this argument is clearly mischaracterizes the intent of the proposal. In this case the desired endpoint is well short of a theocracy. Similarly, the desired endpoint of many proposals aimed at greater government oversight of the economy is well short of complete government control over the economy.

 

[Jimmy Snyder]

I often find the slippery slope argument used to create a strawman argument.

This happens a lot, but it doesn't stop there. The usual sequence is cum hoc ergo propter hoc, followed by extended analogy, non causa pro causa, and converse accident / hasty generalization. From there it's a short step to ad-hominem, mental torture, physical abuse, and finally murder. This is what gives the slippery slope falacy such a bad name.

 

[Frame Dragger]

This happens a lot, but it doesn't stop there. The usual sequence is cum hoc ergo propter hoc, followed by extended analogy, non causa pro causa, and converse accident / hasty generalization. From there it's a short step to ad-hominem, mental torture, physical abuse, and finally murder. This is what gives the slippery slope falacy such a bad name.

:rofl: Excellent example.

 

[Chi Meson]

And then there's the fallacy of using examples a lot more interesting than your main point. The reader goes off on a tangent, which is almost always a bad sine ... unless you're talking about small angle tangents and sines, of course. :rofl:

kudos

 

[Studiot]

I like Ogden Nash's comment,

"You can't get there from here"

 

[Frame Dragger]

I like Ogden Nash's comment,

"You can't get there from here"

I prefer, "There is no there, there." (Gertrude Stein)

 

[Galteeth]

This argument, however, is fallacious if you mischaracterize the endpoint. For example, consider proposals that desire to make America based more strongly on Christian values (e.g. restrictions on abortion). One could argue that such proposals would increase the probability of America becoming a fundamentalist theocracy (e.g. like a Christian version of Iran), but this argument is clearly mischaracterizes the intent of the proposal. In this case the desired endpoint is well short of a theocracy. Similarly, the desired endpoint of many proposals aimed at greater government oversight of the economy is well short of complete government control over the economy.

Ok, but let's say the restriction on abortion was a result of heavy lobbying by a christians. While it might be a fallacy to say that the likely endpoint is a theocracy, it seems correct to say that concession that victory of an interest group makes further victories by that same group more likely, in a political context.

 

[TheStatutoryApe]

On a slightly tangenital note, it is interesting how arguments that are techinally fallacious are often true. There is that argument whose latin name I can't remmeber, the one where you basically say, well this person is an idiot so whatever they say is likley to be idiotic. Although this is not a valid argument against an individual point, it does generally hold true. For example, I don't know for a fact what the position of the reverend Fred Phelps of the "God hates fags" church is towards the flooding of Nashville. It is perhaps possible that he has a sound physical explanation for it. But I would bet everything I had that his explanation is that it was an act of God unleashed as punishment for toleration of homosexuality. I understand the difference between evaluating an individual argument versus the likelihood of future arguments. But it does seem that people who have fundamentally nonsensical world views will produce non-sensical arguments.

I've read that most these arguments are not exactly "fallacious" but "weak". The fallacious argument belongs to formal logic. These arguments are rhetorical. In the case of the slippery slope you could potentially make a good point but the point made in itself is weak and requires more argument to substantiate it. The argument you mention in the above quote, "ad hominem", is a weak argument in that it does not address the actual argument but we can consider the source of the argument and realize that it may be weaker or stronger based on this. It still does not address the opponents argument but pointing out that some idea regarding quantum mechanics is coming from an uneducated fry cook is probably not entirely without merit.

 

[Anticitizen]

I'm of the opinion that the 'slippery slope' fallacy isn't a fallacy at all. It's a valid argument that some incremental changes lead to unintended consequences, because these changes allow for other changes not considered in an original argument. You can't nullify such a 'slippery slope' argument by simply pointing out that it's a 'slippery slope' fallacy - just saying that doesn't mean anything. You must respond by explaining why such changes wouldn't occur and therefore not lead to the 'slippery slope' posited by the person that presented the argument. The fact that you must respond with facts means that the original argument can't be considered a fallacy. Compare with an argumentum ad hominem - you're not required to respond with such an argument with facts in order to nullify it, you can simply point out the fallacy and explain how it's tangential to the actual debate at hand. With a slippery slope argument, you must address the argument and refute it with evidence - screaming 'that's a fallacy' isn't really going to do any good, especially because the argument could be valid.

 

[TheStatutoryApe]

I'm of the opinion that the 'slippery slope' fallacy isn't a fallacy at all. It's a valid argument that some incremental changes lead to unintended consequences, because these changes allow for other changes not considered in an original argument. You can't nullify such a 'slippery slope' argument by simply pointing out that it's a 'slippery slope' fallacy - just saying that doesn't mean anything. You must respond by explaining why such changes wouldn't occur and therefore not lead to the 'slippery slope' posited by the person that presented the argument. The fact that you must respond with facts means that the original argument can't be considered a fallacy. Compare with an argumentum ad hominem - you're not required to respond with such an argument with facts in order to nullify it, you can simply point out the fallacy and explain how it's tangential to the actual debate at hand. With a slippery slope argument, you must address the argument and refute it with evidence - screaming 'that's a fallacy' isn't really going to do any good, especially because the argument could be valid.

The typical slippery slope argument is to state, as noted earlier, that A leads to Z often without any real argument as to why this would necessarily be so. In such a case it would be poor strategy to indulge the slippery slope as you give it some credulity by arguing it. It would be preferable to point out that it is a slippery slope and that you would like to see how the arguer has arrived at Z from A.
It may also be poor strategy to ignore an ad hominem. They are quite effective in that they can leave a lingering doubt of the credibility of a source. Really, why should we listen to this source? Your debate may become an uphill battle.

 

[Anticitizen]

The typical slippery slope argument is to state, as noted earlier, that A leads to Z often without any real argument as to why this would necessarily be so.

The flaw in the 'lack of the real argument' *should* be the basis of the fallacy, then it wouldn't be assailable. I take issue with the fact that it's even *called* a 'slippery slope argument', because it gives someone ammunition to use against someone who's actually employing a legitimate argument about changes leading to unintended consequences. In the current framework, a debater could be legitimately decrying a policy because of the consequences that follow, but will face an opposition that claims that (s)he's just being a 'Slippery Slope-r' and wow-ing an audience into thinking that logical fallacies are codified fact.

 

[Ivan Seeking]

It seems to me that sometimes a slippery slope argument is justified without supporting evidence. Consider for example an event [A], that represents a change in paradigms. One example of this might be legally assisted suicide. While I don't know exactly how assisted suicide [A] could lead to death panels [Z], or legal murder [Z'], laws allowing doctors to [technically] kill patients, do represent a fundamental change in our approach to medicine. I support the right to assisted suicide, but I also recognize that there implicity exists, at least, the potential for a slippery slope. I wouldn't require an argument to defend that point because this is new territory. Undeniably, by its very nature, if left unchecked, the possibility exists that assisted suicide could evolve into something not intended.

 

[Ygggdrasil]

Ok, but let's say the restriction on abortion was a result of heavy lobbying by a christians. While it might be a fallacy to say that the likely endpoint is a theocracy, it seems correct to say that concession that victory of an interest group makes further victories by that same group more likely, in a political context.

In a perfect world, policy making shouldn't be about "winning" and "losing." If one group has a good idea, it should be accepted regardless of whether you like that group or not. Rejecting a good idea because it might empower a certain interest group seems foolish to me. This type of argument also shifts the debate away from discussing why the specific idea is bad to why the group proposing the idea is bad (and could therefore be interpreted as an "ad hominem" fallacy). Of course, voting against another groups' proposals solely to prevent that group from scoring political points is all too common in politics. This is not necessarily a logical fallacy, as much as just a bad idea.

I would agree with the change in paradigm idea, especially in the case where the decision would set some legal precedent that would inform future decisions.

 

[TheStatutoryApe]

The flaw in the 'lack of the real argument' *should* be the basis of the fallacy, then it wouldn't be assailable. I take issue with the fact that it's even *called* a 'slippery slope argument', because it gives someone ammunition to use against someone who's actually employing a legitimate argument about changes leading to unintended consequences. In the current framework, a debater could be legitimately decrying a policy because of the consequences that follow, but will face an opposition that claims that (s)he's just being a 'Slippery Slope-r' and wow-ing an audience into thinking that logical fallacies are codified fact.

As I noted earlier I do not think that these are actually considered "logical fallacies" just "weak arguments". For instance the ad hominem is not necessarily a bad argument. Say we know of prof X who is known to be a liar and a fake (with his telepathy experiments and all ) and someone decides to try to sell us on an idea using data from one of prof X's experiments, are we wrong to point out that he is a known charlatan and dismiss the data until such time as this someone can verify for us its legitimacy? It is an ad hominem but not necessarily poor form even though we have not touched the actual argument; perhaps the argument is not worth bothering to consider in the first place.

How about a strawman? People often make strawmen when arguing by analogy. Project X seems very similar to project Y and considering what happened with project Y we have reservations about project X (I swear the xmen references are not on purpose). It seems a legitimate argument even though it does not touch the issues of project X. It calls out the proponent of X to show us how it is different and whether or not it is really all that different. If the proponent can not effectively do so then perhaps their is reason to hold off on project X.

Red Herring. Is it completely unreasonable to dismiss an argument in the face of another which you find much more compelling and of greater importance? Certainly this can be abused and we can simply dismiss arguments for no good reason but it is not out of the realm of possibility that the argument your opponent is making is simply not worth discussing at this time in the face of greater issues.

The problem with all of these arguments is that they do not directly address the original argument. They are weak in regards to their ability to refute or they never refute anything at all. They require more, and usually can not stand on their own. They can also be abused and opponents can abuse them by dismissing all of your arguments as "slippery slope", "strawman", ect. They are probably best avoided is really the only thing that can be said about them I think.

 

[leroyjenkens]

I think the slippery slope fallacy is that "A will lead to Z". The problem is the certainty of it.

 

[rewebster]

I think a lot of slippery slopes aren't seen until another way to get up the hill is found--for example, the Terra-centric view of things to the heliocentric.

 

[BobG]

I think a lot of slippery slopes aren't seen until another way to get up the hill is found--for example, the Terra-centric view of things to the heliocentric.

I don't think that would be a good slippery slope example, at all.

The heliocentric Copernican model was supposed to be a radical departure (not a small step) right off the bat to get away from a geocentric model was becoming so overly complex in order to force the model and real world observations to synch up that people were beginning to suspect its validity. The problem is that a Copernican model using circular orbits required just as many epicycles and deferents to make it synch with real world observations as the geocentric model did.

The most likely fallacy to be pointed out about the Copernican model at that time was that it wasn't any improvement over the geocentric theory, so how do you choose between them?

At that time, I don't think there's anyone that would have suggested that a heliocentric model would inevitably lead to a model that used elliptical orbits (if they had, it might have defused some horrible arguments between the two circular orbit models). Proposing elliptical orbits was a rather radical proposition in itself. Perhaps one could say a circular heliocentric model at least made a better model possible, since surely people had thought of elliptical orbits before, but just applied them to the wrong model, but I don't see any kind of inevitability, even in retrospect, other than correct models eventually displace incorrect models when better technology to make observations is developed.

Des Cartes' development of Cartesian coordinates and analytic geometry pushing math down the slippery slope to development of calculus would be a better example. Not only is it a natural extension, but the fact that two different people developed calculus independently nearly simultaneously following DesCartes' work is a pretty strong suggestion of the inevitability.

 

[rewebster]

I was looking more at how the Terra-centric view got more and more complex at explaining what they thought was going on ---starting first from a simple view---and each new idea took another step on the slippery slope.