Thursday, July 17, 2014

On "Slippery Slopes": A Response to Richard Mouw

That's the title of my latest essay over at The Catholic Thing. It is a response to a First Things blog post by Richard Mouw. Here's how my piece begins:
My friend, Richard Mouw, a philosopher and former president of Fuller Theological Seminary, has raised an important challenge about the use of counterexamples when making one’s case on certain controversial moral and political questions.

He shares one of the arguments he employs to explain to his friends why he opposes the legal recognition of same-sex “marriage” (SSM): “If we are to operate as a society on the assumption that any sincerely held view about what constitutes a marriage should be granted status in our laws and practices, I have asked, what would keep us from legalizing plural marriages, or even incestuous ones?” Mouw says that his question is often “met with disdain,” with the retort, “[C]an’t you do better than a ‘slippery slope’ argument?”

He finds the retort frustrating, since, “some slopes are indeed slippery, and we do well to approach them with caution.” In other words, if you advance the truth of principle X in order to justify practice Y, something that you support, why not also accept practice Z, something that you reject, since it too is entailed by principle X?

So, for example, if you support the legalization of marijuana for competent adults on the principle that “one has a right to do whatever one wants to one’s body without directly harming others,” then that principle not only justifies marijuana legalization but also the decriminalization of hard drugs like heroin.

A person who resists this entailment by saying it’s a slippery-slope fallacy is confusing the fallacious form (often called a “causal slippery slope”) with the legitimate form of the slippery slope (often called a “logical slippery slope”). To point out that a principle entails something undesirable is not a slippery-slope fallacy. It’s an acknowledgment that principles have a logic of their own, so to speak.

>>>continue reading


Donalbain said...

But if you have an actual argument against polygamy, then use THAT argument when someone tries to advocate polygamy. If you have an actual argument against incestuous marriage, then use it when someone tries to advocate for incestuous marriage. If you say gay marriage is wrong because incest is wrong, then you are magnificently missing the point and you are showing that you have no actual reason that the rest of us should take seriously in the argument on the rights of gay people to marry.

Theodore Seeber said...

The sad thing is that in many ways, gay marriage isn't at the top of the slippery slope, but in the middle. It started with contraception, then pornography, then free love, then abortion....we're quite a ways down the slope already, and I very much doubt we're at the bottom yet.

daveyork7 said...

I agree. Sin begets ever greater sin. It goes into deeply darker things the further we go down. At the bottom lies death.

Theodore Seeber said...

Death of the soul, I hope you mean. Death of the body can come somewhat before the bottom. Along the way for those who don't die, is enjoying the death of others.

Don't believe me? do a web search on "she asked me to kill her". I refuse to link to any of those stories.

Zxenia Cvenka said...

It seems to me that your argument about a slippery slope is a slippery slope. Gay marriage is OK. Most Catholics believe so.

Marc said...

I am curious about whether the marijuana example can be applied to smoking too. It will look like this:

So, for example, if you support the legalization of smoking for
competent adults on the principle that “one has a right to do whatever
one wants to one’s body without directly harming others,” then that
principle not only justifies smoking legalization but also the
decriminalization of marijuana (and mutatis mutandis) hard drugs like heroin.

LionelAndrades said...

Dominus Iesus, Redemptoris Missio carry the Cardinal Francesco Marchetti Selvaggiani mistake

hjill said...


I think you have misunderstood. The arguments against polygamy and incestuous marriage are largely the same as those against SSM, and that is precisely the point. Those with whom he disagrees on SSM do not see that the logic of their position would necessitate as well these other forms of marriage, yet they maintain that these other forms should not be given the same legal status. Thus, they hold a logical contradiction.

If, however, you believe we should legally equate polygamous, incestuous, homosexual, and heterosexual marriages, then you do not hold this contradiction and this line of reasoning does not apply to you.

Donalbain said...

If the argument against SSM stood on its own, there would be no need to invoke polygamy. But the arguments I would use against polygamy are essentially pragmatic rather than moral so while I support SSM, I do not support (or oppose) polygamy.

If your argument against X relies on the notion that you also oppose Y, then I contend your initial argument is weak.