The Core Principles

Scientific thinking rests on five commitments:

• Falsifiability — a claim must be possible to disprove (the line philosopher Karl Popper drew between science and non-science)
• Controlled testing — change one variable at a time so you know what caused the effect
• Replication — one result means little; repeated results mean something
• Peer review — let others check your work before you trust it
• Updating — when evidence contradicts your hypothesis, change the hypothesis, not the evidence.