I have decided to make my way through some of the more common logical fallacies. Some of my readers may be unfamiliar with some of them, and I know that I have made the mistake of utilizing them, generally without thinking, from time to time both here and in my really real life. This series will not be a comprehensive list of every possible logical fallacy; such a list would be impossibly long and I would lose interest. But there are some gooders out there, and I felt that I would do my best to talk about some of them, what makes them fallacious, how to spot them, and why they are effective.
The first one I will approach is the Gambler’s Fallacy, because I think it’s one of the most common fallacies we use in our daily lives. It ultimately preys on our general misunderstanding of mathematics, particularly the use of numbers to confound and our lack of understanding probabilities.
If you flip a coin 9 times, and you have 5 heads and 4 tails, what are the odds that the next flip is tails? The answer is 50/50. Every flip of the coin has the same chance of heads or tails. The preceding 9 flips are totally and completely irrelevant to the outcome of the tenth.
The fallacy isn’t limited to gambling, though. Let me give you an example. Suppose that Janet has 13 children, and they are all girls. She becomes pregnant again. Is she having a girl? The gambler’s fallacy would imply that somehow she has to have a boy because the odds on all of those girls leading to another girl are impossibly long. The reverse is also true, however, that someone could commit the reverse gambler’s fallacy by saying that it would have to be a girl because the universe has been obviously giving Janet girl after girl after girl.
The reality is that there a an immense number of factors that could play into the outcome. One of the most notable that I am aware of is the timing of the sex that leads to conception. Male sperm move quicker, women sperm live longer. Is it possible that our friend Janet has a natural pattern for when she is most intrigued by sex, either consciously or not, and tends to have it earlier, allowing the male sperm to die off before ovulation? Of course it is. But if she has sex outside of that rhythm, a boy may be more likely.
But that’s hardly the point. From the parents’ perspective, the outcome is binary – male or female. That’s why the fallacy gets applied. Now, you’ll notice that the fallacy applies both ways. This is because the odds based on previous pregnancies are what we are talking about here, and those odds have no bearing whatsoever on the current pregnancy.
Another example of this fallacy, but again relating to babies, is the idea that your lump is likely to be a boy because boys run in the family. Boys don’t run in your family. Sperm run in your family. I have personally never heard of a hereditary condition that resulted in only sperm of one gender being created, so your family having all those boys would be a matter of random chance and nothing more.
The way to spot this fallacy is the phrase, “Well, the odds are…” Unless two events are causally related, then the odds are nothing special.
That doesn’t mean that odds can’t come into the conversation, but people like to see relationships between events that are not directly related to one another. There are actually many logical fallacies that cater to this desire, but we’ll get to more of those. The gambler’s fallacy is an easy one to spot because it relies on the assumption either that a result has to be a value simply because that hasn’t value is past due, or that a result has to be a certain value simply because it’s always that value.