Why I Don’t Believe in the Butterfly Effect, Part 10
Part 10 of 12: The Butterfly Effect and the Slippery Slope
The slippery slope is the idea that if you let something slide once, then something more serious will follow, and then something even more serious will follow that ………… and before you know it, something totally unacceptable will happen. An example of a slippery slope argument would be, “If you let your kids stay up late, then before you know it, they’ll be doing drugs.”
A classic example of a slippery slope is found in the children’s book If You Give a Mouse a Cookie. In this book, a little boy gives a cookie to a mouse. Then the mouse asks for a glass of milk to go with it, and the boy obliges. The mouse keeps asking the boy for more and more elaborate things, such as a mirror, and the boy keeps on obliging. The book goes full circle at the end, since the mouse’s final request is for another cookie. But regardless, the book illustrates a slippery slope: if you give a mouse a cookie, then before you know it, you’ll be giving him a mirror.
Most slippery slope arguments are false. Most of the time, when you let something slide once, it does not lead to drastic consequences. That’s because the slippery slope is a logical fallacy. And it turns out that the logical fallacy behind the slippery slope is the same as the logical fallacy behind the butterfly effect.
To be sure, the slippery slope is not the same thing as the butterfly effect. There are some notable differences between these two ideas.
The most important difference between them is that under the slippery slope, the predicted drastic consequence is relevant to the initial event, whereas under the butterfly effect, there is no relevance at all. For example, if I say, “If you give a mouse a cookie, then before you know it, you’ll be giving him a mirror,” then even though that’s probably not true, it at least makes logical sense, because giving the mouse a mirror is relevant to giving him a cookie. They both involve you giving him an object. However, under the butterfly effect, the supposed drastic consequences have no relevance to the initial event. If I say, “A butterfly flapping its wings in Brazil causes a tornado in Texas,” there is no relevance between a tornado in Texas and a butterfly in Brazil. And in that sense, the butterfly effect is even more absurd than the slippery slope.
There are a few more differences as well. One is that the slippery slope is associated with the humanities, while the butterfly effect is associated with the sciences (and science fiction). Another is that the slippery slope predicts a specific consequence to the initial event, whereas the butterfly effect implies that it is impossible to predict anything.
Another important difference is that some slippery slope arguments may actually be true, whereas the butterfly effect is never true. For example, let’s say you make a New Year’s Resolution that you will go to the gym and work out every day. Let’s say you follow it perfectly for three months. But then one day in April, you decide that you’re just too tired, and you don’t go that day. Yeah, that’s probably the end of your New Year’s Resolution. A week later, you’ll probably take another cheat day. Three days after that, you’ll probably take another. By June, you probably won’t be going to the gym at all anymore. (In mathematical terms, your decision to take that first cheat day substantially reduced the probability that you would follow your New Year’s Resolution on most days throughout the whole year.) Once you’ve broken a rule once, the rule has much less power over you than it did before.
So that’s an example in which the slippery slope is real, at least to some extent. However, I don’t think the butterfly effect is ever true. It does sometimes happen that something that seems trivial turns out to be very important, but that’s not because of the butterfly effect (see Part 6). In its purest form, I don’t think the butterfly effect is ever true.
But in spite of these differences, the slippery slope and the butterfly effect are similar ideas. They both involve the theory that small things lead to big things, because the small things cause a chain reaction. And they are both built on the same logical fallacy.
Both the butterfly effect and the slippery slope are based on the following premise: if A causes B, and B causes C, and C causes D, ……… and Y causes Z, then A led to Z. As soon as you let A happen, you’re letting Z happen. If you just hadn’t done A, then Z wouldn’t have happened. (And according to the butterfly effect, something totally different would have happened instead.)
This premise is fallacious because it assumes that there is only one node in world history, which was at the time when A happened. In reality, the universe either is or is not deterministic. If it is deterministic, then there was only ever one way that things could have unfolded anyway. Meanwhile, if it is not deterministic, then there is a whole branching tree of possibilities, such that A doesn’t control everything that follows. (See Part 4.) And if you plot the probability that Z will happen as a function of time, you can see that A does not have a significant effect on the probability of Z (see Part 5).
Once you have identified this logical fallacy, you have debunked both the slippery slope and the butterfly effect.
When it comes to the slippery slope, this is well-known. Most people have heard of the slippery slope, and most people know that it’s fallacious. You will never hear someone say, “I think all slippery slope arguments are true.” Many commentators have written about why the slippery slope is a fallacy, and if you go to the Wikipedia article about the slippery slope, it will immediately tell you that it’s a fallacy.
But when it comes to the butterfly effect, this is not well-known. There are a large number of people, including some very smart people, who believe in the butterfly effect. I have had several professors who have promoted it. (They usually promote it within some sort of bound, but they still promote it.) And if you go to the Wikipedia article about the butterfly effect, it will not immediately tell you that it’s a fallacy. In fact, most of the article seems to be promoting it.
This begs the question: if smart people reject the idea of the slippery slope, why would they believe in the butterfly effect? Why would they reject one version of the logical fallacy but accept another?
The reason has to do with the way the science is presented. Proponents of the butterfly effect have heard of the results of scientists like Edward Lorenz. They may have also heard that scientists have found similar chaotic behavior in many other systems, including the motion of asteroids, the economy, and even the behavior of groups of people. That’s why they take chaos theory seriously.
These smart people are correct about these scientific findings — they just don’t realize that they’re misinterpreting them (see Part 9). They don’t realize that it’s fallacious to conclude that small changes cause big changes. They don’t realize that they’re making the fallacy of assuming that there was only one node in world history.
It’s a shame. The butterfly effect and the slippery slope are based on the same logical fallacy. They are two different versions of the same fallacious idea. The logic that disproves the slippery slope also disproves the butterfly effect. Thus, if smart people reject the slippery slope, they should also reject the butterfly effect.
Part 2: The Butterfly Effect in Pop Culture
Part 3: The Wrong Way to Disprove It
Part 5: Responding to Arguments in Favor of the Butterfly Effect
Part 6: Exceptions (And Why They Aren’t Really Exceptions)
Part 7: Three Wrong Ways to Discuss Alternative History
Part 8: The Right Way to Discuss Alternative History
Part 9: How I Would Interpret Lorenz’s Observations
