Related to: Leaky Generalizations, Replace the Symbol With The Substance, Sneaking In Connotations

David Stove once ran a contest to find the Worst Argument In The World, but he awarded the prize to his own entry, and one that shored up his politics to boot. It hardly seems like an objective process.

If he can unilaterally declare a Worst Argument, then so can I. I declare the Worst Argument In The World to be this: "X is in a category whose archetypal member gives us a certain emotional reaction. Therefore, we should apply that emotional reaction to X, even though it is not a central category member."

Call it the Noncentral Fallacy. It sounds dumb when you put it like that. Who even does that, anyway?

It sounds dumb only because we are talking soberly of categories and features. As soon as the argument gets framed in terms of words, it becomes so powerful that somewhere between many and most of the bad arguments in politics, philosophy and culture take some form of the noncentral fallacy. Before we get to those, let's look at a simpler example.

Suppose someone wants to build a statue honoring Martin Luther King Jr. for his nonviolent resistance to racism. An opponent of the statue objects: "But Martin Luther King was a criminal!"

Any historian can confirm this is correct. A criminal is technically someone who breaks the law, and King knowingly broke a law against peaceful anti-segregation protest - hence his famous Letter from Birmingham Jail.

But in this case calling Martin Luther King a criminal is the noncentral. The archetypal criminal is a mugger or bank robber. He is driven only by greed, preys on the innocent, and weakens the fabric of society. Since we don't like these things, calling someone a "criminal" naturally lowers our opinion of them.

The opponent is saying "Because you don't like criminals, and Martin Luther King is a criminal, you should stop liking Martin Luther King." But King doesn't share the important criminal features of being driven by greed, preying on the innocent, or weakening the fabric of society that made us dislike criminals in the first place. Therefore, even though he is a criminal, there is no reason to dislike King.

This all seems so nice and logical when it's presented in this format. Unfortunately, it's also one hundred percent contrary to instinct: the urge is to respond "Martin Luther King? A criminal? No he wasn't! You take that back!" This is why the noncentral is so successful. As soon as you do that you've fallen into their trap. Your argument is no longer about whether you should build a statue, it's about whether King was a criminal. Since he was, you have now lost the argument.

Ideally, you should just be able to say "Well, King was the good kind of criminal." But that seems pretty tough as a debating maneuver, and it may be even harder in some of the cases where the noncentral Fallacy is commonly used.

I’d like to tell you all a story.

Once upon a time I was working for a charity – a major charity – going door-to-door to raise money while pretending it wasn’t sales.

This story happened on my last day working there.  I didn’t know that at the time; I wouldn’t find out until the following morning when my boss called me up to fire me, but I knew it was coming.  For weeks I’d been fed up with the job, milking it for the last few dollars I could pull out, hating every minute of it but needing the money.  The Sudden Career Readjustment would come as a relief.

So on that day, my last day, I was moving slowly.  I knocked on one particular door and there was no response.  I had little desire to walk to the next one, however, and there was an interesting spider who’d built its web below the doorbell.  I tapped its belly with the tip of my pen, and it reacted with aggression – trying to envenom and ensnare the tip of my ballpoint.  I must have been playing with it for a good minute or so when the door suddenly opened.

A distraught woman stood before me.  After a brief period of Relating I launched into my pitch.

Note: The primary target of the post is not professional, academic evolutionary psychology. Rather, I am primarily cautioning amateurs (such as LW regulars) about some of the caveats involved in (armchair) evpsych and noting the rigor required for good theories. While the post does also serve as a warning to be cautious about sloppy research (or sloppy science journalism) that doesn't seem to be taking these issues into account, I do believe that most of the researchers doing serious evpsych research are quite aware of these issues.

Evolutionary theories get mentioned a lot on this site, and I frequently feel that they are given far more weight than would be warranted. In particular, evolutionary theories about sex differences seem to get mentioned and appealed to as if they had an iron-cast certainty. People also don't hesitate to make up their own evolutionary psychological explanations. To counterbalance this, I present a list of evolutionary psychology-related problems, divided into four rough categories.

Problems in hypothesis generation

Rationalization bias. We know that human minds are very prone to first deciding on a desired outcome, then coming up with a plausible-sounding story of why it must be so. In general, our minds have difficulty noticing faulty reasoning if it leads to the right conclusion. It's easy and tempting to come up with an ad-hoc evolutionary explanation for any behavior, regardless of whether or not it actually has any biological roots.

Over-attributing meaning. Humans also have a strong tendency to attribute meaning to random chance. We might easily come up with explanations that are unnecessarily complex, and try to make everything into an evolved adaptation. For instance, humans tend to avoid thinking about unpleasant thoughts about themselves. A contrived evpsych explanation might be that this is evolved self-deception: by not acknowledging our own faults, it makes it easier for us to deceive others about them. But mental unpleasantness tends to be correlated with harmful experiences: we avoid situations where we'd be afraid, and fear is correlated with danger. It could just as well be that the mechanism for avoiding mental unpleasantness evolved from the mechanism for avoiding physical unpleasantness, and we avoid thinking unpleasant thoughts of ourselves for the same reason why we avoid poking our fingers at hot stoves. (Example courtesy of Anna Salamon.)

Alternative ways of reaching the goal. Eliezer previously gave us the example of the scientists who thought insects would under the right circumstances limit their breeding, but the insects ended up eating their competitors' offspring instead. We can only cover a limited part of the space of all possible routes evolution could take. While ”but another hypothesis might explain it better” is admittedly a problem all scientific disciplines face, it is especially acute here, since we have very little knowledge of what life in the EEA was actually like.

Problems in background assumptions

Did a genetic path to the adaptation exist? Evolution works by the rule of immediate advantage: for mutation X to reach fixation, it has to provide an immediate advantage. It's well and good to propose that under specific circumstances, organisms that developed a specific behavior would have gained a fitness advantage. But that, by itself, tells us nothing about how many mutations reaching such a behavior would have required. Nor does it tell us anything about whether all of those intermediate stages actually conferred the organism a fitness benefit, making it possible for the final form of the adaptation to actually be reached.