Wishful thinking

Start with this observation:

1. Commonly used forms of fallacious reasoning are typically distortions of good forms of reasoning.

For instance, affirming the consequent is a distortion of the probabilistic fact that if we are sure that if p then q, then learning q is some evidence for p (unless q already had probability 1 or p had probability 0 or 1). The ad hominem fallacy of appeal to irrelevant features in an arguer is a distortion of a reasonable questioning of a person’s reliability on the basis of relevant features. Begging the question is, I suspect, a distortion of an appeal to the obviousness of the conclusion: “Murder is wrong. Look: it’s clear that it is!”

Now:

2. Wishful thinking is a commonly used form of fallacious reasoning.

3. So, wishful thinking is probably a distortion of a good form of reasoning.

I suppose one could think that wishful thinking is one of the exceptions to rule (1). But to be honest, I am far from sure there are any exceptions to rule (1), despite my cautious use of “typically”. And we should avoid positing exceptions to generally correct rules unless we have to.

So, if wishful thinking is a distortion of a good form of reasoning, what is that good form of reasoning?

My best answer is that wishful thinking is a distortion of correct probabilistic reasoning on the basis of the true claim that:

4. Typically, things go right.

The distortion consists in the fact that in the fallacy of wishful thinking one is reasoning poorly, likely because one is doing one or more of the following:

1. confusing things going as one wishes them to go with things going right,

2. ignoring defeaters to the particular case, or

3. overestimating the typicality mentioned in (4).

Suppose I am right about (4) being true. Then the truth of (4) calls out for an explanation. I know of four potential explanations of (4):

1. Theism: God creates a good world.

2. Optimalism: everything is for the best.

3. Aristotelianism: rightness is a matter of lining up with the telos, and causal powers normally succeed at getting at what they are aiming at.

4. Statisticalism: norms are defined by what is typically the case.

I think (iv) is untenable, so that leaves (i)-(iii).

Now, optimalism gives strong evidence for theism. First, theism would provide an excellent explanation for optimalism (Leibniz). Second, if optimalism is true, then there is a God, because that’s for the best (Rescher).

Aristotelianism also provides evidence for theism, because it is difficult to explain naturalistically where teleology comes from.

So, thinking through the fallacy of wishful thinking provides some evidence for theism.

A fallacy in non-deductive reasoning

If we think about the large variation of appearances among donkeys, it is very probable that:

1. Some donkeys look very much like horses.

Now we run this argument:

2. D is a donkey that looks very much like a horse. (Existential instantiation on 1)
3. D looks very much like a horse. (By 2)
4. D is a horse. (Probabilistic inference from 3)
5. Some donkey is a horses.

We might make the inference from (3) to (4) more explicit by making use of:

6. If D looks like a horse, probably D is a horse.

I think this is related to Rowe's argument from evil.

The metaextrapolation fallacy

Let's suppose on Friday I am running a public star night. I am looking forward to this and checking the NOAA cloud cover forecast for Waco for that Friday night, starting the preceding Saturday. On Saturday, the forecast for that Friday is 75% cloud cover, let's suppose (I made up the data). On Sunday, the forecast is 70%. On Monday, the forecast for Friday is 62%. On Tuesday, Friday's forecasted cloud cover is 60%. Today, Wednesday, the forecast for Friday says 51%. What should I estimate Friday's cloud cover at? Well, a reasonable line of thought is that I can extrapolate from the data, and suppose that on Friday the forecast for Friday will say something like 40%, and since Friday's forecast for Friday will be the most accurate, my current estimate for Friday's cloud cover should be around 40%. Or I can give the appearance of being scientific and run a linear regression, and get the same answer from a pretty good regression with R²=0.95.

But this could be called the metaextrapolation fallacy. The weather data has already been pored over by experts—or by algorithms designed by experts. On Wednesday, these experts have access to the raw data behind the Sunday, Monday, Tuesday and Wednesday forecasts for Friday, and based on all that raw data, they extrapolated to 51% cloud cover. If they've done their job well—and of course that is always a question—my second-guessing extrapolation from their extrapolations should be trumped by their last extrapolation. In other words, I should suppose the cloud cover will be 51%, and that the trend I observed is just due to chance.

If, however, I find that in successive weeks there are similar trends in forecasts, I will then have reason to think that I've identified something in the data that they haven't. For if their estimates are the best possible, we would expect that the distribution of forecasts for a particular date, as one gets closer to the date, typically has no statistically significant trends. If there tend to be trends, then we might start forming hypotheses, like that longer term forecasts overestimate cloud cover. But to do that, we need more data than just these five points. (This post builds on, and qualifies, some of the remarks here.)

A variant of the genetic fallacy

Consider the following argument form:

1. p is believed because of argument A.
2. If A is a good argument, then q.
3. Not q.
4. Therefore, not p.

This is a kind of cross of the genetic fallacy with a denial of the antecedent (in the conditional: If A is a good argument, then p). For example:

5. The Immaculate Conception (the doctrine that Mary was saved by grace alone in the first moment of her existence) is believed because of the argument that Jesus would be subject to original sin if Mary was.
6. But if Mary's original sin would have infected Jesus, then the original sin of Mary's parents would have infected Mary, and so on, and hence all of Mary's ancestors would need to be without original sin.
7. But not all of Mary's ancestors are without original sin.
8. Therefore, the Immaculate Conception is false.

Notice, however, that there is an argument form in the vicinity of (1)-(4) that is better. Namely, we replace (4) with:

9. Therefore, the belief that p is not justified.

However, if we do that, we need to read (1) as saying "p is only believed because of argument A". But people are not very good at figuring out the reasons why they themselves believe something, and are much worse at figuring out why others believe something (that explains why so much political discussion is heated—for it is often difficult for people to figure out why someone might take a political position that disagrees with theirs, unless that person is stupid or vicious). So if the implied epistemic agent in (1) and (9) is someone other than the person offering the argument (1)-(3),(9), the argument is likely to be unsound in step (1). I think that when the argument form is found in the wild, it is common for (1) to fail.

Furthermore, it is important to keep constant the epistemic agent constant between (1) and (9).

I think the Marian case likely screws up on all of these counts. First of all, in (5) the epistemic agent is likely some ordinary believer or at best an incautious rookie apologist. In the analogue of (9), the epistemic agent is the Church. Second, even in the case of the ordinary believer or the rookie apologist, (5) ceases to be true if we read "is believed" as "is only believed", because in fact the ordinary believer and the apologist believe in the Immaculate Conception not just on the basis of their flawed argument, but primarily on the basis of the Church's authority.

Moreover, arguments of the form (1)-(3),(9) are often annoying to the interlocutors. I remember a job interview where a candidate tried to convince me that I only rejected his or her view because of thinking about a topic under the influence of a certain other position. This bit of mind-reading not only was incorrect (I can be accused of many things, but not of that particular influence; I rejected the candidate's view cause the conjunction of its claims obviously entailed some absurd proposition that we were both committed to the denial of), but I found it annoying and a bit offensive, and the other members of the interview committee did not like it either. That was a somewhat different version of the genetic fallacy, but the genetic fallacy is generally annoying.

There are places for arguments of the form (1)-(3),(9). But when one gives such arguments, danger is all about.

A false principle concerning desire

I am not the first to discover this particular fallacy—in fact, part of this post is based on ideas I got in conversion from somebody who got them from something he read. But the ideas are no less fun for being mainly not mine.

Consider the following argument for psychological hedonism, the doctrine that the only thing we pursue is pleasure:

1. Whenever we pursue something other than pleasure, we pursue it because it gives us pleasure. (Premise)
2. Therefore, what we really pursue is the pleasure it affords to us.

Not only is (1) false, but (2) does not follow from it. The following inference is invalid:

3. We pursue x because it gives us y.
4. Therefore, what we really pursue is y.

In fact, taken literally, (4) contradicts (3), since if "what we really pursue" is y, and y is not x, then we are not pursuing x (to pursue is the same as to really pursue). But even if we weaken (4) to:

5. Therefore, we pursue y

the inference is still invalid. If I am trying to find a woman who offers water to my camels (cf. Genesis 24), it does not follow that what I am really pursuing is water for my camels. Perhaps I just want the kind of woman who gives water to my camels. Likewise, one might want a particular fig tree in the garden because it yields figs, not because one wants the figs, but because yielding figs is largely constitutive of the health of a tree, and one wants only healthy trees in the garden.

Perhaps the inference works better if we replace (1) by:

6. Whenever we pursue something other than pleasure, we pursue it only because it gives us pleasure.

It's easier to see how (2) might be thought to follow, but (6) now begs the question against the non-hedonist. In any case, the inference is still logically invalid.

In fact, it is even incorrect to conclude from the claim that I seek x solely because it yields y that I want y at all. Suppose that, whimsically, I desire a magical hat that yields rabbits. I only want the hat because it yields rabbits—my whim is that I want to have rabbits pop into existence out of a hat. I can want such a hat for such a reason without having any desire for the rabbits. The rabbits themselves are a nuisance, and I would have no interest at all in rabbits that come into existence in any way other than out of a hat.

It might be objected that then I don't want the hat just because it yields rabbits, but I want the hat because it is a hat that yields rabbits, and so this isn't a counterexample to the inference type. But if so, then the non-hedonist need only say that she doesn't want x just because it yields pleasure, but she wants an x because it is an x that yields pleasure.

The fallacy here also occurs in the Lysis in the argument that if I am friends with x because x yields y, then what I am really friends with is y.