Just how hard is it to tell those apart anyway? Or: bad reasoning in the real world pt 3.

well, guess what I’m going to talk about today…

Senator Bernadi today suggested that allowing gay people to marry each other would lead down a slippery slope to inter-species marriage. See the story here.

Now what most people will (correctly) focus on is the gay-bashing and soon, I’m sure, that Abbott has used the opportunity to get rid of him to try and soften his image after Labor swung back on character with the punching a wall thing (not saying that Bernadi is a nobody who no one had ever heard of before today and thus a good scape goat or anything. Or that he can now say he ordered the vote against marriage equality for reasons other than gay people are icky)[1]. What I’d like to talk about is slippery slope arguments more generally.

In general slippery slope arguments all make the same mistake. To see it let’s consider a rather better argument which turns up in moral philosophy. When wondering if abortion is morally acceptable one might consider something like the following (simplified) reasons:

1. It is not morally acceptable to kill a person (ceteris paribus[2]), so if an embryo or fetus is a person abortion is not morally acceptable.
2. We all agree (for the sake of argument) that new borns are persons and it is not acceptable to kill them
3. But there is little difference, and no morally important difference, between the new born and it as it was an hour before birth.
4. There is little difference, and no morally important difference, between the new born as it was an hour before birth and as it was two hours before birth.
5. repeat on until we are all the way back at the embryo.
6. There is no clear dividing line between the new born and the embryo
7. An embyro is as much a person as the new born and thus
C. Abortion is not morally acceptable.

Now a central issue in the abortion debate is whether or not a fetus is a person, but this argument provides us with no insight whatsoever that can help us decide. The key inference in this argument is the inference that because the fetus is, for moral considerations, equivalent at any two adjacent time points (the difference between the fetus now and in an hour can’t be enough such that it is a person in an hour but not now) that it is equivalent across the time span. This is a key step in the slippery slope argument, we can’t tell any two “adjacent points” (speaking abstractly) apart, so if we concede one of the points we end up conceding them all. In Bernadi’s case it was we can’t tell gay marriage from polygomy and we can’t polygomy from marrying a non-human animal, therefore we can’t distinguish gay marriage from marrying a non-human animal. If we allow gay marriage we should therefore allow marriage to non-human animals, that would be gross so we’d better not allow the whole spectrum. The abstract “adjacent points” are who should be able to marry who. Now you’ll notice that these slippery slope arguments run in slightly different ways, but the important error will turn out to be the same.

One way to look at the error made here is from the point of view of definitive boundaries. It seems that moving back in time we can’t identify a definitive point before which the fetus was not a person and after which it is, so that any appearance that its is not a person early on is merely an illusion. What this ignores, however, is the possibility of fuzzy boundaries, a boundary that is extended in time in this case. There maybe a time period within which we could say we just can’t tell if the fetus is a person or not, but it doesn’t follow from this that we can’t tell the difference between a living child and an embryo. We just have to examine both as they exist. By analogy consider that there is no definitive point at which we would say that a greenish blue becomes a blueish green, but that doesn’t mean we can’t tell blue from green (choosing the right colours for this example is hard!). When did mammal-like-reptiles become mammals?

Now it’s even easier if we want to consider Bernadi’s argument as there is a clear dividing line between loving more than one person and fucking a sheep, I’m not sure why one would think that these acts constitute “adjacent points” that slippery slope arguments need, (but I suspect that his speech was more to give Abbott a chance to look reasonable than to actually make a point)[3]. At any rate my point here is that slippery slope arguments easily avoided by taking a view which is both broader and more specific. Fuzzy boundaries are hard, but we can still tell things apart.

with love

[1] not a political strategy blog Glenn, stay focused.
[2] all else being equal. This is a phrase used to acknowledge complications without having to list them all, e.g. it is not morally acceptable to kill a person- assuming they aren’t trying to kill you etc.
[3] fine i couldn’t help myself


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