Philosophy Fridays: Slippery Slopes


Every now and then, on a Friday, I’ll step into the deep waters of Philosophy, ramble away on some idea and maybe even interact with something I might be reading. Most of the time, a real philosopher could probably read my drivel and speak into it offering a corrective—but for now I’ll speak from ignorance. After all, it is Friday; what better way to have fun than with philosophy. In this post I’ll answer the question “Are slippery slope arguments always fallacious?”  in under 700 words. Heh.

What is it anyway? This is how The Nizkor Project defines it.

  1. Event X (or might) occur(s)
  2. Therefore event Y will inevitably happen.

This is clearer, they say, when there are a bunch of steps between (A) and (B).

But then is that always true? Is it fallacious to point to a Rube Goldberg machine and say that dropping this dime will inevitably lead to that umbrella popping the balloon? So a real causal chain would render it non-fallacious. has a similar definition but they admit that the argument isn’t always a fallacy.

  1. Accepting one policy or action occurs.
  2. Therefore a series of policies or actions will occur.

They point out that this can be made valid by giving a reason why (A) leads to (B). So here, they’d want a visible causal chain between (A) and (B) but why does that have to be the case? I know when I hit this button, Mario jumps but I don’t see any of the processes behind it. Indeed, I’m still warranted in thinking that my action causes Mario to jump.

Valepress lists four types of slippery slope arguments (with an unfortunate of word count):

  1. Action A gives precedent for future action B.
  2. The argument employs a lack of cutoff point. Accepting A isn’t distinguished from B.
  3. Action A is causally linked to Action B.
  4. The argument combines (a), (b) and (c).

And, they admit, sometimes it’s a fallacy and sometimes it isn’t; that seems to underscore some of the problems I’m wrestling with here. After all, the domino effect in (c) isn’t fallacious if there really is a domino effect (obviously causal chain).  And (b) seems to have merit in legal systems as follows.

Eugene Volokh (pdf warning and I’d also suggest his conclusions are off) points out that that slippery slope is a proper concern in a legal system that has historically shown slippage. One court makes a legal decision with tight distinctions, sometime later a new court uses that previous decision as precedence without any of the distinctions made in the previous court, to make a new decision.

So here’s Volokh on something he references as a classical Slippery Slope Argument which sounds a lot like (a) and (b) but not (c) above.

  1. Unopposed  legal Action A (which isn’t that bad or even moderately good)
  2. Increases the likelihood of a supposedly much worse legal action B.
  3. (Psychology) A and B are distinguishable now but parties might not distinguish them later.

But, let’s say that someone argues if you keep playing in the street you’re going to get killed by a vehicle. Depending on the street, the action of playing in the street creates an environment that one can be killed by a vehicle, but if it’s some seldom used dirt road out in Middle of Nowhere then this seems pretty unlikely.

Maybe when action (A) creates an environment that gives precedence for future action (B) where (B) is plausible, the slippery slope argument has warrant.

But here  (A)-Opposers might point out (B) isn’t plausible now. But that still doesn’t render the argument fallacious since (B) need only be plausible in the environment of (A). Landing a six on die (B) isn’t plausible if there are no dice, but it is rightly within the realm of probability once the die is thrown (A).

So are slippery slope arguments always fallacious? Nope.

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