Is a slippery slope argument a logical fallacy?

No!! Not OBLIVION!!!

(Version française un peu plus bas.)

Not too long ago, I went into an argument with a number of my friends from Québec about the future of the french language in the province. For those of you not too familiar with the topic, here is the rundown. People in Québec are left with the impression that the future of french is compromised in North America. This impression is mostly built on the growing number of immigrants who never learn french once they arrive in the province, or the number of flourishing businesses dealing almost exclusively in english, which is mostly happening in Montréal.

From there, a lot of people are tempted to extrapolate that trend to the oblivion of french in North America. In terms of proportions, we see the french culture receding (although I am pretty sure that in absolute numbers, it is not) and we seem confident that french speaking people will eventually become so apathetic towards their own culture that they will give it up and start speaking english. The pressure of sharing the province with an increasing number of non-french speaking people ought to do it. This is an archetypical slippery slope argument.

I was actually having this exact discussion on two separate occasions while I was in Québec in October. Every time I pointed out that this was a slippery slope argument,  I was met with a “so what?” type of reaction. One of my friend explained that slippery slopes are not necessarily logical fallacies and I have given some thought to this.

Let’s first define the slippery slope a little bit better. I am quite happy with the definition I find on Wikipedia:

“A slippery slope argument states that a relatively small first step leads to a chain of related events culminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom.”

The rest of the Wikipedia article is quite informative, and even touches the point I want to make. But let me take a crack at it anyway because I want to make it as clear as possible.

Here’s an example of a correct slippery slope argument. There is a candle on the table on which I am writing this. If I tip the candle, it will start rolling and it will eventually fall off the table. Then, it will probably light up the fluffy carpet at my feet. At this point, I will run away screaming “I KNEW IT!! MOOUHHAHAHAA!!” and the carpet on fire will produce enough heat to light up the table, which will light up the rest of the room on fire, and the house will eventually burn down.

I can demonstrate that each step in this sequence of events will happen once the candle has been tipped (am I really this mad?), therefore I must take precautions not to tip the candle. A slippery slope argument where each step can be shown to be likely to happen is a valid argument. If there is a single step that is shown to be unlikely, the argument won’t lead where it is supposed to. In the previous example, one of the steps is definitely not very likely. Still, I will try not to tip the candle. I don’t want the neighbours to see me screaming like that.

The Drake equation makes for an interesting parallel. If stars are forming often enough, if enough of those stars have planets, if enough of these planets can support life, if enough of these planets actually develop life, if some of the lifeforms become intelligents, if these intelligent lifeforms can emit radio waves in space, if they can emit them for long enough, we should be able to find them. The probability of the final outcome is understood as the product of the probabilities of all the steps. The probability of each step must be high enough to guarantee that the next one is also possible. Astronomers, astrophysicists and biologists are in the slow process of estimating each of these probabilities, but we don’t know what most of them are yet.

The point is, it is a lot of work to evaluate the likelihood of the outcome predicted by the slippery slope argument. Unless there are serious data and logic proving that each step in the slope is either causally linked or correlated, it is hard to take that kind of argument seriously. A slippery slope is not a fallacy in itself, but it requires explanatory support to be valid. When slippery slopes arguments are being thrown away in daily discussions, they rarely have any form of support backing them up. They are supposed to be self-evident, and that is exactly when they are fallacies.

So is french on its way to extinction in North America? Is that particular slippery slope validated? I have yet to be convinced. The fact that I am writing mostly in english on this blog may look extremely ironic to the proponents of this view. I am still extremely skeptical that this will happen, but that is a topic for another post!

_______________________________________

Est-ce qu’une pente fatale est un argument fallacieux?

Il n’y a pas si longtemps, j’ai eu une discussion avec quelques uns de mes amis du Québec à propos du futur de la langue française en Amérique du Nord. Pour ceux qui ne sont pas trop familier avec le sujet (vous n’êtes probablement pas l’un ou l’une d’entre-eux si vous lisez ceci en français!), voici un court résumé. Les gens au Québec ont l’impression que le futur du français en Amérique du Nord est incertain. Cette impression est surtout basée sur le nombre croissant d’immigrants qui n’apprennent jamais le français une fois arrivé dans la province ou bien le nombre de compagnies qui prospèrent en conduisant leurs affaires presque exclusivement en anglais. Ceci se voit surtout à Montréal.

À partir de ces faits, beaucoup de gens sont tentés d’extrapoler cette tendance jusqu’à l’oubli de langue française en Amérique du Nord. Si on regarde les proportions, la culture française semble être en déclin (malgré qu’en nombres absolus, elle ne l’est probablement pas) et on est confiant que les gens qui parlent français vont finir par être tellement apathique envers leur propre culture qu’ils vont tout simplement la laisser tomber et passer à l’anglais. Partager la province avec un nombre toujours grandissant de gens qui ne parlent pas français nous mène tout droit vers cette triste conclusion. Ceci est un exemple typique de pente fatale.

J’ai eu cette exacte discussion à deux occasions lorsque j’étais au Québec en Octobre dernier. À chaque fois que j’ai indiqué que cet argument était une pente fatale, on m’a répondu que ça ne rendait pas l’argument invalide. Un de mes amis m’a expliqué qu’une pente fatale n’est pas nécessairement un sophisme et ça m’a fait réfléchir.

Commençons par définir la pente fatale un peu mieux. Je suis satisfait de la définition (la version anglaise est une peu plus générale que la version française, alors je traduis la définition anglaise) que j’ai trouvé sur Wikipedia:

«Une pente fatale implique qu’un premier pas relativement petit dans une direction mène à une chaîne d’événements reliés qui culmine en un effet majeur, comme un objet qu’on pousse légèrement au bord d’une pente et qui continue jusqu’au bas de celle-ci.»

Le reste de l’article Wikipedia (la version anglaise) est très intéressant, et il touche même le point que je tente de communiquer. Cependant, laissez-moi tout de même l’élaborer parce que je voudrais qu’il soit aussi clair que possible.

Voici un exemple d’une pente fatale qui est valide. J’ai une chandelle allumée sur la table sur laquelle j’écris ceci. Si je renverse la chandelle, elle va rouler jusqu’au bord de la table. Elle va tomber sur le tapis à mes pieds et elle va y mettre le feu. À cet instant, je vais sortir en courant et en criant: “JE LE SAVAIS!! MOOUHHAHAHAA!!”, et le tapis en feu va éventuellement allumer la table, qui va allumer le reste de la pièce et la maison va passer au feu.

Je peux démontrer que chaque étape dans cette séquence va se produire (suis-je vraiment débile à ce point?) dès que la chandelle tombe, donc je dois faire attention de ne pas renverser la chandelle. Une pente fatale dont chaque étape est définitivement probable est un argument valide. Si une seule étape est improbable, l’argument ne mènera tout simplement pas à sa conclusion. Dans l’exemple précédent, une de ces étapes est vraiment improbable. Malgré tout, je vais faire attention afin de ne pas renverser la chandelle. Je n’aime pas l’idée que les voisins me voient crier ainsi.

L’équation de Drake offre un parallèle intéressant. Si suffisamment d’étoiles se forment, si suffisamment d’étoiles ont de planètes, si suffisamment de planètes peuvent supporter la vie, si suffisamment de ces planètes ont vraiment de la vie, si ces formes de vie deviennent intelligentes, si elles découvrent comment envoyer des ondes électromagnétiques dans l’espace, si elles émettent assez longtemps, on peut découvrir la vie extraterrestre du confort de notre salon. La probabilité de cette conclusion est le produit des probabilités de chaque étape. La probabilité de chaque étape doit être suffisante pour assurer la possibilité de l’étape suivante. Les astronomes, astrophysiciens(ennes) et biologistes progressent lentement mais surement dans l’estimation de ces probabilités, mais nous sommes encore loin d’un estimé fiable.

Où je veux en venir est qu’il faut énormément de travail pour valider une pente fatale. À moins qu’il y ait des données fiables et/ou une bonne logique qui appuie chaque étape dans la pente, il est difficile de considérer la pente fatale comme un argument sérieux. Il faut expliquer la relation causale entre les étapes, ou au moins prouver qu’il y a une corrélation. Une pente fatale n’est pas un sophisme en soi, mais elle requiert une bonne explication pour être valide. Quand la pente fatale est utilisée dans les discussions mondaines de tous les jours, elle est rarement supportée adéquatement. Elle est considérée évidente en soi, et c’est exactement dans ce cas qu’elle a le minimum de validité.

Alors est-ce que le français est en voie de disparaître en Amérique du Nord? Est-ce que la pente fatale qui mène vers cette destination est valide? Je ne suis toujours pas convaincu.  Le fait que j’écris surtout en anglais sur ce blog peut paraître ironique à ceux qui défendent cette thèse. Je maintiens un grand doute que ce scénario se réalise présentement, mais ceci est un sujet pour un autre jour!

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7 Responses to Is a slippery slope argument a logical fallacy?

  1. Greg M. says:

    I don’t like where you are going with this Michel. First you claim the slippery slope argument might be fallacious, and then you will move on from there, poking holes in appeals to authority, straw men, induction-on-one and ad hominem attacks. What will be left? We wouldn’t be able to have a single argument that won’t degenerate into aimless frustration. Where will this end?

    On the other hand…

    While slippery slope arguments aren’t really logical they may have value in certain contexts. They only make any sense by appealing to human nature particularly the social nature of the human animal. For example English common law operates on the principal of legal precedent. There is a very real slippery slope in law. One precedent can set off a chain of rulings that require some level of consonance between them.

    Look at the Patriot Act and Bush era civil liberties rights violations. They are continuing unabated under the Obama Administration. Bush seems to have put us on a slippery slope. Deregulation, the “just a little extra tax breaks for rich and there will be job creation with trickle down effects” idea was (rightly) labeled the start of a slippery slope to our current global clusterfrack. Of course some slippery slopes turned out to be nonsense (legalizing pornography didn’t lead to a sex-crazed perverted population behaving like animals while civilization collapsed around us, so far so good on this one), while others have been just that.

    French in North America? I’d say without the extra paranoia and vigilance , e.g. declaring every concession as the start of a slippery, it may very well be on that slippery slope. People give up language grudgingly, and nearly everyone will buy into the slippery slope reasoning, so I’ll place my bet on French sticking around quite a while. 😉

  2. I am one of the proud Québec debater Michel talked about. My point was mostly that the slippery slope reasonning is a tool to use to construct possible indesirable outcomes. The drowning of the french minority in the english sea of people is quite possible ; as our relative weight in Canada and Nort America gets smaller and smaller, it’s gonna be more and more difficult to continue to live in French and our very own mix of a culture.

    Some point could be made that our culture is quite irrelevant to people’s happinnes or well being (sort of world citizenship). That’s a point I won’t accept for a simple reason ; diversity is the key of everything when you talk about living things. And as far as I know, we’re living (hope so!) and so is culture (sort of). And there’s a lesson to be learned from agricultural science and/or genetics ; the more you push for uniformity and performance, the lesser the genetic pool, the more problems you have. The day where everybody will act, dress, eat and act according to the same beliefs and principles will be a sad day indeed, and we will have lost much.

    I would add a reasonning I learned in Economics ; A simple human being taking a rationnal decision that is good for him is good for the majority. But if everybody takes the same decision, it could be catastrophic. Think Wal-Mart (everybody going there means difficult times for small shop owners and employees), think buisness opportunitues (if everybody develops the same unexploited idea, the market will collapse)…the examples are numerous. The point is that if a person kind of gives up on living his personnal and/or professionnal life in french because there’s so much people in Montreal that don’t want to learn French, it’s just kinda sad. But when that scenario repeats itself, it’s culturicide (TM).

    There has been plenty of examples in Montreal specificly where people chose to live there because of the european heritage, the nighlife, the restaurant and so on, but won’t make any effort to learn French. A quite revealing article has been written in La Presse recently, where a young woman, originaly from Toronto, chose to live in Montreal, lived there 8 years, did not learn a single word of French. But she went to Togo and learned a dialect spoken by less then 5000 very remote Africans. Kudos for that, but seriously, how about learning something about the people and the language you chose to live with? (Sorry, I can’t find the article I refer to).

    I can understand that attitude for tourists. I mean, I wouldn’t learn German just to go to Berlin for a few days (I’d learn “Another beer please”, “thank you”, “Sorry I threw up on you”, etc.). But when you go fill the gas tank and can’t be talked to in french by that young lad who takes your cash, it pisses people off. On a personnal note, when I asked that dude if he could talk to me in french (playing the “Je ne parle pas Anglais” card), his reaction was very evocative ; I would have asked him to chew his own toes that he would not have been more disgusted. I was pissed. And rightly so. Why am I the one having to make an effort ; Quebec is a french speaking majority, I am the costumer, I freakin speak freakin french.

    Those kind of example, when added, kinda prove the point of the slippery slope we’re on, as french-canadians. The reasonning may be flawed, but the reality is there. There may not be a doomsday clock ticking, but there are warning signs.

    PS : I don’t think slippery slope is flawed as an argument. To me, the slope is -X^2 ; when you step foot on 1, it’s no big deal. But as you get further, it gets tricky. Slippery slope ; try only if you want to risk trouble.

    PPS : English being my second language, I may have commited grammatical horrors ; I’m sorry. Also, my arguments may be blurry ; my vocalubary is more limited in the sheakspear tongue (intended).

    • Michel says:

      Salut Étienne!

      Bienvenue sur mon blog! Je vais répondre à ton argumentation, mais en même temps j’ai tellement de choses à dire sur le sujet que j’ai l’intention d’en faire un nouveau billet. Ton anglais se tient très bien en passant 🙂 Je ne publierai pas immédiatement ma réponse, parce que je dois écrire mon billet sur le boson de Higgs suite au séminaire qui s’est tenu au CERN mardi de cette semaine.

      Néanmoins, c’est agréable d’avoir une telle discussion par écrit, ça donne le temps de penser!

  3. Josh McNeill says:

    Sorry to comment on such an old post but:

    A friend of mine recently tried to explain to me (while drinking) that the slippery slope argument is not actually a fallacy. I wasn’t able to comprehend his argument at the time so I tried to Google it today and wound up here. The thing that confuses me is that the claim seems to be that if a slippery slope argument is used and turns out to be valid then it’s not a fallacy but if it’s used and turns out to be invalid then it’s a fallacy. This doesn’t make much sense to me as I’ve always looked at fallacies as *arguments that are always fallacious but sometimes still valid* as opposed to *arguments that are either fallacious or valid*.

    You seem like smart people, what’s the deal?

    As for French. As a non-French speaking American who has often had to deal with moody Québécois francophone tourists who don’t understand that French is not spoken in New Jersey, I’d still be sad to see the language diminish up there. As a comparison, Cajun French in Louisiana has been in decline for a while supposedly because Cajun parents avoid teaching it to their kids for fear that they won’t be fluent enough in English in an English-speaking nation. I could see a change in ratio of French-speaking to English-speaking people in Quebec creating similar circumstances. I also experienced this in San Francisco where some 40% of the population is Chinese yet many of the kids there don’t know a lick of their parents’ language, presumably because of the lack of practical value it has. There’s also evidence that this is happening to the Navajo language; I’ve seen interviews with young people whose parents wouldn’t teach them the language for fear that they’d end up speaking English with a noticeable accent. Anecdotally, it would seem that languages have trouble thriving in the absence of strong practical reasons to use them.

    • Michel says:

      Hi Josh, thanks for the comment. You’re right, the answer to the question in the title of the post is No. I guess it needs a little bit of context to understand why I raised the question at all. It’s simply that in CÉGEP in Québec we have philosophy classes, and I remember (as many people of my generation) that the slippery slope was thrown in with the logical fallacies when it was taught. So yeah, I guess in the post I just overlooked the question itself and switched directly to tackling under what kind of circumstances can a slippery slope have any kind of validity.

      You are right, languages do disappear under a lack of practical reasons to use them. But that’s not the case in Québec. The example you give of the Cajun and the Navajo, well, they don’t number in the millions and they don’t have governmental policies to support them. The forces at play are different. My point in this post is that one needs to explore these forces to see if the extinction of French will happen. Common sense says it is possible. But only a more in-depth analysis can inform us on whether this is probable or not.

      Oh, and don’t worry about these obnoxious tourists, we’re not all like that. I think we all have our share of idiots 🙂

  4. Kurtis says:

    The problem I usually have with this ‘slippery slope’ argument is that people are saying something will ‘definitely’ happen. There is no guarantee of anything ever happening 100%. People who think otherwise are simply fools. When using these arguments you should use ‘most likely’ or ‘might’ in your arguments, so it gives the opponent sufficient room to counter that argument. People who say something will definitely happen are difficult to argue with because they presume that something is guaranteed to happen, no matter the cause and/or the effect (which is wrong). People who bring up these If someone disagrees with ‘French will most likely eventually go given the nature if immigration’ but does not provide a reason why they disagree, then they’re not worthy of debate with. You’ve provided them the reason for your thinking, it’s their job then to provide you a counter argument OR give you something to add to your thought process which might change your own thinking.

    In my personal opinion, you got it right with your candle example. It’s still technically a ‘logical fallacy’ as far as I know, but you have not said that anything will ‘definitely’ happen. If you knock the candle off the table, it might roll onto the floor and it might set it on fire. There is no guarantee of either happening but the point is to take precautions to prevent the least favourable thing happening (don’t knock it off). Of course, you have to understand the opposite side of this as well; if you knock the candle off the table, the flame might go out in the process and will roll on the carpet safely. You have to use your judgement then to decide what you think is the more likely scenario. You take the environment into consideration then. If you knock the candle off a table which is only a meter high, then the chance is quite substantial. If the table is miles high (for saying sake), the risk is nigh irrelevant. There’s also the type of candle; is it a candle that’s designed to remain lit in motion? Most probably not.

    Another example I can think of is a glass off a shelf. The fallacy based argument is that it would ‘if the glass falls off the shelf onto the floor, it will smash to pieces.’ What this argument doesn’t realise is that there might be different kinds of floor; carpet, wooden, tiled, etc. What it doesn’t include is information about the height of the shelf. Carpet will provide cushioning, but only to a certain level. Of course, you would have to question how the glass would ‘fall off’ in the first place as well.

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