The next mental model is one that I already use from time to time, but I thought was worth unpacking a bit more. Occam’s Razor is simply stated as “entities should not be multiplied unnecessarily“, but that can be a little hard to apply. I prefer the more useful version of:
“when you have two competing theories that make exactly the same predictions, the simpler one is the better”
This can apply to medicine when making a diagnosis. While your symptoms might be caused by a super rare disease, if they also match up with a common cold, that’s more likely the answer. Doctors often use the phrase “when you hear hoofbeats, think horses, not zebras” to express it and direct their thinking.
This also often comes into play with conspiracy theories, both large and small.
If you fail an important test, you may have two possible explanations:
- You should have studied more.
- Your teacher is out to get you.
Or if you’re considering whether the earth might be flat:
- Hundreds of thousands of researchers are being paid off, every rocket launch has been faked, and there are armed guards surrounding Antarctica.
- The earth is an sphere (well, an oblate spheroid), like we’ve all known for years.
This doesn’t mean it’s foolproof. You might indeed have a mystery illness, or your teacher might be mad at you because of your attitude, but most times Occam’s Razor will reveal the truth.
When searching for an answer Occam’s Razor is a great place to start, but that doesn’t mean you should always stop there.