| dave ( @ 2009-06-18 12:38:00 |
| Entry tags: | faith, god, math, odds |
The uncommon occurence.
Many people, including myself, have a system for determining whether they are being spoken to by God. Most of the time it involves counting sources involving/talking about the same subject. The more sophisticated people calculate the odds of those occurrences happening within the a given time window, but it amounts to a similar task of counting occurrences. The more people hear about a particular subject, within a week, from different sources, the more they are inclined to think it is an important subject to consider or reconsider. This post is not meant to debunk that thought, but to give it a closer examination and a slight refining.
The way odds are calculated, a situation with certain factors that can yield different results is set up and repeated. The number of times a certain outcome happens with the same circumstances divided by the total number of repetitions equals the total percentage chance of that event happening with those circumstances. This is easy to calculate for things such as coin flips, dice rolls, etcetera. When calculating the odds of two events happening at the same time, the odds of each multiplied together give the total odds chance. (No 50% x 50% is not 250%, you must represent the chances as fractions, or as a decimal between 0 and 1 with .5 being 50%. So 50% x 50% = 25%) When several events occur within a limited time frame, yes the odds get really small just using the previous math. The problem is the math makes one assumption. None of the events are in any way related to any of the other events. That's right. If you have two events where one event happening has a chance of causing another, the odds cannot be straight multiplied. The new formula ends up being:
If A is an event that has a 50% chance of happening and when A happens there is a 50% chance of B happening. Also, B has a 50% chance of happening whether or not A happens. Total odds of A and B happening are: (odds of A)50% * ((odds of B)50% + ((odds of A triggering B)25% * (odds of B not triggering)50%)) = 31.25%
Just by A having a 50% chance of triggering B, it increases the total odds of both happening form 25% to 31%. If B also has a chance of triggering A, you end up with a recursive loop in the equation. (as a reply to this post I will run the geometric series calculation) This will increase the odds, but as a diminishing return.
So, take the following situation. During the season of Lent. Herbert is driving in his car listening to the radio and hears a special on K-love about fasting. He then talks to his buddy, and his buddy happens to talk to him about fasting in passing conversation. Then Herbert goes to church the next day and the pastor talks about fasting in the sermon. Then he looks at a friend's blog that talks about fasting. You might say that this is a really rare occurrence, however. How many of those people that Herbert talked to might have heard the K-love special. How many of who are left heard the sermon? How many of who are left also read the blog. And how many people tend to talk about what they have heard recently? And it is during the season of Lent where people tend to talk about fasting anyway. Because all of these events are more than likely related, the odds of what happened to Herbert are actually not as miniscule as what it might seem.
Take a different situation. No where near the season of Lent. Herbert is digging through an old box of books and runs across a book about fasting. He then reads a newspaper that has an article about fasting. Is taken to the airport later to fly to Greece, with a layover in Germany. While in the Germany airport the person he ends up talking to brings up fasting as part of the conversation without previous mention. On the way back, he reads the air mall catalog that has a book on sale about fasting. Then as he is going to his car in the airport, his sister from another state calls and says she is going on a short term fast. Most of these events had nothing to do with each other, have a relatively low chance of occurring individually, and happened within a short span of time. This would be a truly rare occurrence.
Again, this post is not to have people completely rule out rare occurrences in their lives as God talking to them, just a challenge for people to more closely examine the circumstances by which these events occur. Therefore ruling out the seasonal hype, chain reactions of publishing, and topics that continuously travel the internet in circles.