What does it mean that explicit relationships replace assumptions?

Writing down how two ideas relate prevents assuming a connection that does not exist.

Example: In 1967, psychologist Loren Chapman presented participants with lists of word pairs and asked them to estimate how often certain pairs appeared together. Participants consistently overestimated the co-occurrence of semantically related pairs — like 'bacon' and 'eggs' — even when the actual data showed no correlation between them. The participants were not lying or lazy. Their brains were filling in relationships that felt natural, bypassing what the data actually showed. Chapman called this illusory correlation: the tendency to perceive a relationship between two things based on expectation rather than evidence. His follow-up research with Jean Chapman in 1969 demonstrated the same effect among trained clinicians interpreting psychological test results — experts with years of experience still saw relationships that did not exist in the data, because those relationships matched their prior assumptions. The only reliable antidote was forcing the relationship to be stated explicitly and then checked against evidence.

Try this: Pick a domain where you make frequent judgments — your work, a hobby, a recurring decision. Write down five pairs of things you believe are related (e.g., 'morning exercise' and 'productive workday,' or 'client responsiveness' and 'project success'). For each pair, write one sentence articulating the specific nature of the relationship: is it causal, correlational, temporal, or something else? Then ask yourself: what is my actual evidence for this relationship? Have I observed it systematically, or does it just feel true? Mark each relationship as 'verified,' 'plausible but untested,' or 'assumed.' You will likely find that most of your believed relationships fall into the third category — and that the act of writing them down already begins to change which ones you trust.