Simpler or Simplest?

I could have named this post “Positive or Comparative?” and I’ve mentioned this in the past. Do a search in the upper right corner to see earlier posts.

The rule has to do with putting “-er” or “-est” at the end of an adjective. The rule is below the quote.

An author of the new Venus study told me that she’s come to the uneasy conclusion that Occam’s razor — the principle that given two conclusions the simplest one is usually correct — points to phosphine being created by life, not unknown geochemistry on Venus.

https://www.axios.com/newsletters/axios-space-ba9f4735-4119-4364-9582-3b8ea45bb8dc.html

The writer is Miriam Kramer, and I don’t know who the editor was, but here’s a picture of the scientist holding a model of phosphine:

Okay, the rule:

• When you compare two things, use the comparative; -er
• When you compare three or more things, use the superlative; -est
• When you’re not comparing but just describing, don’t put anything on the adjective.