Charles Sanders Peirce drew a distinction that most working scientists never encounter by name but live by daily: the difference between a hypothesis you are testing and a hypothesis you are *entertaining*. Entertaining, for Peirce, was a specific cognitive act — holding an idea provisionally aloft, uncommitted, while continuing to work. He called the generative habit of proposing such ideas 'abduction,' but the more interesting thing he noticed was that scientists often collapse this phase too quickly, converting entertainment into commitment before the idea has earned it. The cost isn't just wasted effort. It's that commitment changes what you notice: once a hypothesis graduates from entertained to tested, anomalies that contradict it start to feel like noise rather than signal. Peirce's practical remedy was almost embarrassingly simple — maintain a written list of hypotheses you are merely entertaining, separate from the one you are currently pursuing. The list is not a backup plan. It is a cognitive preservative, keeping alternative framings alive precisely because the act of active testing tends to kill peripheral vision.

What hypothesis are you currently *testing* that you originally meant to only *entertain* — and when exactly did that shift happen?

Drawing from American Pragmatism — Charles Sanders Peirce (Collected Papers, c. 1878–1914)