Specify what would falsify your belief before you look at evidence

Write down what evidence would prove you wrong before you go looking.

Why it works

Specifying the falsifier before seeing evidence creates a commitment that makes motivated reasoning harder: you cannot easily dismiss the disconfirming evidence after the fact if you agreed in advance that it would count. This is Popper’s demarcation criterion applied as a cognitive practice: a belief without a specifiable falsifier is not doing real epistemic work, and naming the falsifier forces clarity about what the belief is actually claiming.

How to do it

1. Write the belief clearly as a testable claim.
2. Complete the sentence: "I would change this belief if I discovered that…"
3. Make the condition specific and observable, not vague ("if most people disagreed" is not a falsifier).
4. Check: would this evidence genuinely change your mind, or are you writing something that will never actually occur?

Evidence

Popper’s falsificationism is a normative philosophical standard rather than an empirically tested cognitive technique. Pre-registration in science (specifying hypotheses and analysis plans before seeing data) operationalizes the same principle and has been shown to reduce outcome-reporting bias. (mechanistic)

Falsificationism is philosophically contested (Kuhn, Lakatos, Feyerabend all raised objections); as a practical heuristic for everyday reasoning it is widely endorsed, even if not the complete picture of how science works.

Sources

• Popper (1959), The Logic of Scientific Discovery — original formulation of falsifiability as the demarcation criterion

Common mistake

Writing a falsifier that sounds specific but is actually constructed to never come up — "I would change my mind if the evidence were overwhelming" is not a falsifier, it is a blank check to keep believing.