You have probably heard of Occam’s razor before. If you haven't, Occam's razor is a principle from Philosophy that is often simplified to the assertion that the simplest answer is normally the correct one.
This was my understanding of Occam's razor for a long time. Do the simple thing. Seems straightforward enough.
Turns out this is mostly correct, but it doesn't explain the "why" behind the instruction. The question remains: Why are simple things correct more often than complex things? I'll defer to William of Occam himself for the answer to this:
"Among all hypotheses consistent with the observations, the simplest is the most likely” — William of Occam
The simplest option isn't inherently the best choice.
It's the best choice because it makes the least assumptions. Each assumption comes with the probability that it’s wrong. When you multiply these probabilities together, the overall error rate compounds.
Let's say you're predicting the weather. It's a more unlikely proposition to say that it's going to snow than predicting it will be cold. In order for it to snow, you are making an assumption that the temperature is below freezing. On the other hand, predicting temperature is a much simpler prediction without as many assumptions, and therefore is more likely to be correct, all else equal.
In practice, you have to make assumptions quite often. Complex decisions often require complex thinking. But as often as you think. Occam's razor is a popular mental model for good reason.
If you can minimize assumptions than you minimize the probability of being wrong. That’s what Occam’s razor really means.