Mental Models Are Singular by Default
People typically construct a single mental model of a situation and reason from it as if it were complete, without spontaneously generating alternative models.
Why this is an axiom: This empirical regularity from mental models theory (Johnson-Laird) identifies a fundamental cognitive default that cannot be reduced to simpler mechanisms. It's not that people are incapable of generating alternatives—it's that doing so requires explicit effort that doesn't occur spontaneously.
Key evidence: Experimental research shows that when people reason about spatial arrangements, logical relationships, or causal scenarios, they construct an initial mental model and typically stop there. They fail to systematically explore alternative configurations that are equally consistent with the given information. This explains characteristic reasoning errors: people confidently conclude that certain inferences are valid when they're actually only possible-but-not-necessary. Only when prompted to "think of other ways it could be" do subjects generate alternatives, revealing the incompleteness of their initial model.
Curriculum connection: This axiom is crucial for understanding systematic biases in human reasoning and judgment. It explains why people prematurely commit to interpretations, miss possibilities in decision-making, and struggle with certain logical tasks. It motivates explicit techniques for generating alternatives and considering multiple hypotheses—skills that don't come naturally but can be deliberately cultivated through practice.