Knowledge Marketplace
My First Million

My First Million

The best business ideas come from noticing what's working and doing it better, faster, or for a different audience.

Back to Mental Models

Useful vs True Belief Framework

Prioritize whether a belief is useful to hold over whether it's objectively true, since beliefs influence behavior and outcomes.

Decision Rule

When evaluating what to believe, ask 'What behaviors will this belief create?' rather than just 'Is this true?'

How It Works

Beliefs shape actions, actions shape results. Sometimes believing something positive (like 'I'm lucky') creates better outcomes regardless of objective truth.

Failure Modes

Believing useful but false things that create long-term harm

Ignoring important truths because they're uncomfortable

Using this as excuse for wishful thinking

Applying this to areas where accuracy is critical (engineering, medicine)

Example Decision

Choosing to believe you're a 'lucky person' because it makes you take more chances and notice opportunities, even if luck isn't objectively real.