When is the slippery slope argument invalid?

[MichaelP3]

Maybe?

But then I heard cigarette smoking leads to marijuana. Out of all the smokers I know, one smokes marijuana and it wasn’t because he was looking for it.

From a viewpoint that is somewhat related to this. Something like contraception lead to abortions and SSA never made sense to me. The "make love not war hippy movement " was during the Vietnam war. Will we blame the war now for the declining morals?

In the end if one is looking for a connection you will find it.

 

[Rhubarb]

That’s not what slippery slope is.

“If I shoot myself in the head, I’ll die” isn’t a slippery slope.

 

[Arkansan]

Every single example I’ve ever seen given of what a “slippery slope” argument is, has been an argument from evil consequences.

 

[phil19034]

Slippery slope arguments are never valid. They are always invalid. They can’t be applied with logic.

Validity has to do with the structure of an argument. Slippery slope doesn’t work because the structure doesn’t lead to conclusions that are sure. For example, the argument “if you allow X, how long until You happens?” Y isn’t entailed by X at all. There is no logical connection. (In terms of actual logic).

“You allow your kids to eat candy? How long until they’re doing heroin?!” That’s the same logical structure as “if you legalize gay marriage, how long until polygamy?!”. And they’re both invalid.

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This is totally false. Your argument is based on the faulty idea that all logic must be scientific. This is not true, because logic can be based on science and/or philosophy. Your argument is a perfect example of science-ism.

While, slippery slope arguments are not scientific, because they cannot be proven with the scientific method, they CAN be logical because they can be supported by solid philosophical arguments rooted in classical philosophy.

 

[phil19034]

Rhubarb:

Going to my example again, I’d bet most heroin addicts did indeed start with candy. But candy wasn’t causal to their heroin use. And plenty of people eat candy who have never touched hard drugs - in simpler terms, candy use doesn’t necessarily lead to heroin use.

what about marijuana leading to harder drugs? is that illogical?

No, it is not illogical. It’s unscientific, but it’s not illogical.

“Logic” & “Logical” does not automatically equal scientific.

 

[Rhubarb]

I am discussing the matter from a purely philosophical standpoint. Because I have a degree in it. Logic is the opposite of science. Logic is deduction. Science is induction.

A slippery slope argument is always fallacious. Ask any logician out there. Like I said, an invalid argument only means the logic is faulty - the reasoning is bad. Bad reasoning can lead to true conclusions. Just like a broken clock is right twice a day.

Your talk of science and scientism is baffling to me. I didn’t bring up science, induction, or empiricism.

 

[Rhubarb]

I think you’re confused about what scientific means.

Show the logical entailment between consumption of sugar leading necessarily to the consumption of heroin. That’s what a slippery slope argument like the one I used means to show.

Science would be running double-blind repeated studies to see if there is a correlation between eating candy and shooting heroin. And if I had to guess, I would guess that there is a correlation of heroin users eating candy before moving into heroin. But there isn’t a statistically significant correlation between candy eaters moving onto heroin.

 

[MichaelP3]

Show the logical entailment between consumption of sugar leading necessarily to the consumption of heroin.

I do not have a degree in Philosophy but this made me think.

On the same basis (for many other arguments) and equal absurdity, some will argue well all who consume heroin have consumed suger. And even make a connection?

 

[Rhubarb]

I addressed that in my last post. I’m sure you’re right all heroin users ate candy first in their lifetime.

The relevant connection is candy users who do it do not move onto heroin. I haven’t done a study but I’d bet dollars to donuts there is no correlation between candy use and heroin use - because the vast majority if candy users do not go on to heroin use. There is no causal connection.

And that’s one reason why slippery slope is fallacious. It means to suggest a logical entailment (that candy use entails heroin use) that doesn’t exist - even though heroin users did assumedly start candy before heroin.

 

[MichaelP3]

And I believe so for many many other arguments who use the same rationale.

Regards

 

[Rhubarb]

I mean let me just use the elephant in the room. The usual meme is “if we allow gay marriage, polygamy isn’t far behind”.

This is fallacious because nothing about the logical concept gay marriage entails the logical concept of polygamy. BUT perhaps there is something else going on - a cultural trend, ways of thinking, demons, whatever, that could be moving sexual mores in a certain direction. THAT would be the causal connection. And that isn’t necessarily a slippery slope argument.

 

[phil19034]

Show the logical entailment between consumption of sugar leading necessarily to the consumption of heroin. That’s what a slippery slope argument like the one I used means to show

OK, we might not be totally on the same page.

I know that Slippery Slope Arguments are always a fallacy, but they don’t always violate the Rules of Rational Argumentation. Because, when used correctly, a Slippery Slope Argument isn’t meant to be “valid.”

I might be wrong, but my assumption is that the OP wasn’t asking about validity in terms of formal debate / formal logic, but rather rational argumentation.

Perhaps, I’m wrong, but that’s how I took it. I viewed the intent of his question to determine whether Slippery Slope Arguments can be effective in making a rational argument – which they can be when actually being used rationally.

7. Slippery Slope

Slippery Slopes, Red Herrings, Straw Men and More!

criticalthinkeracademy.com

God Bless

 

[Rhubarb]

I mean, a slippery slope argument can be used to convince. If that’s all you’re concerned about sure. Though that is considered a form of sophistry. I’d also consider it unethical advocacy.

I can’t imagine a rational argument that uses faulty reasoning. Informal fallacies always contain faulty reasoning.

 

[Kei]

Slippery slopes can still posit correct truths, but the way they are framed are incorrect.

Say it is well known that loosening morals leads to loosening morals further.
Instead of saying, “If we legalize swear words on Movies, then what’s next, people are gonna start blaspheming the Name of God!” it would be fallacious because they aren’t necessarily connected. It is a form of non sequitur. It is still probable that they will get used to swear words and then get more loose with their language.

 

[Rhubarb]

An invalid or fallacious argument can lead to a true conclusion, that’s right. In fact, there’s something called a 'fallacy fallacy" - it’s fallacious to assume a conclusion is false just because the argument is fallacious. Exactly because a fallacious argument can have a true conclusion.
“We can’t land on the moon, or eventually we’ll be inventing rap music!” This is totally fallacious (because there’s no logical connection between the two), but it turns out the conclusion is true. (Because we did land on the moon, and then eventually invented rap music)

I teach my students that the big problem with slippery slope arguments is that they’re lazy. An argument like yours can be fleshed out and expressed in a non-fallacious way. If I may use an example, and I’ll bullet-point it just to keep things straight because it’ll take a bit

1. I live in a small town that is built around a major US interstate
2. The town’s economy depends on “cute small town” tourism to their Main Street where there are tons of shops, and California Gold Rush tourism.
3. But the Interstate has these annoying 3 stop lights on them that snarls traffic - especially on holidays or weekends when Bay Area traffic all comes up the hill to go to Tahoe.
4. So they want to build an overpass to keep traffic flowing past my town.

People say “If you build an overpass, it’ll lead to our town dying!” That’s a slippery slope (only exactly what I put in quotes) However, if they expand on it - “We have data from towns all across California that show when highways overpass or bypass towns, they shrivel and die, so we don’t want that for our town” That isn’t a slippery slope argument, that’s an inductive argument. The slippery slope argument relies on fuzzy non-connections and fears (as the page of the Illustrated Book of Bad Arguments I posted tells) in place of facts, evidence, and logical entailments.

 

[goodcatholic]

But then I heard cigarette smoking leads to marijuana. Out of all the smokers I know, one smokes marijuana and it wasn’t because he was looking for it.

From a viewpoint that is somewhat related to this. Something like contraception lead to abortions and SSA never made sense to me. The "make love not war hippy movement " was during the Vietnam war. Will we blame the war now for the declining morals?

In the end if one is looking for a connection you will find it.

Interesting post. Thanks. I smoked cigarettes and never went to marijuana. I’ve just got this idea in my head, that weed changes your brain and you start to think “yeah man cool, let’s try that”

 

[goodcatholic]

Because it implies we are “going down to Hell”?

 

[goodcatholic]

it is not illogical. It’s unscientific, but it’s not illogical.

“Logic” & “Logical” does not automatically equal scientific.

So evidence based. There has been no evidence or research data to show that marijuana leads to harder drugs?

 

[goodcatholic]

I might be wrong, but my assumption is that the OP wasn’t asking about validity in terms of formal debate / formal logic, but rather rational argumentation.

Just debating on a forum like this. Thinking skills that can be acceptable to a majority of readers.
I think legalising same sex marriage has inevitable consequences such as limiting free speech, not being able to criticise homosexuality in public. And it seems perfectly logical to me to wonder if someone wants the right to marry their sibling, for instance. “human rights, after all”. “I have a right as a human being to equality.”

 

[goodcatholic]

“If we legalize swear words on Movies, then what’s next, people are gonna start blaspheming the Name of God!” it would be fallacious because they aren’t necessarily connected.

That seems perfectly logical to me. A genuine fear. Almost certainly would happen.