Step 1: Focus on core goals, filter out most issues, and don't get bogged down in trivial matters; Step 2: When facing key issues, don't get stuck on the only available options—identify the core goal, turn the problem into a short-answer question, and find a third option; Step 3: Avoid cognitive biases, activate System 2, and engage in slow thinking; Step 4: Establish criteria, score all options, and compare the quantified results. —— Chapter 21 How to Make Scientific Decisions

1. The four-step scientific decision-making process is a funnel from broad to narrow: first eliminate unimportant matters, then break through the option framework, then exclude biases, and finally quantify
2. Step 1: Focus on goals, filter trivial matters. Most struggles are not worth worrying about—focus on core goals
3. Step 2: Find the third option. When facing a multiple-choice question, don't just look at the options themselves—restore the goal → turn the multiple-choice question into a short-answer question → find a win-win solution
4. Step 3: Avoid cognitive biases. Three major biases: Reflection Effect (gambling more when facing losses), Certainty Effect (seeking stability when facing gains), Anchoring Effect (being anchored by a preconceived value)
5. Activate "System 2" (slow thinking) and replace intuitive reactions with rational analysis
6. Step 4: Quantify decision-making. Assign weights → score item by item → calculate weighted sums → let numbers speak
7. 37% Rule (Wheat Ear Theory): For one-time choices with no turning back, spend the first 37% of the time observing only to establish a benchmark, then immediately choose the first option that exceeds the benchmark
8. The essence of the third option is to break out of the "either-or" framework and find a new solution that maximizes the interests of all parties

• Case of choosing a spouse: Use a quantitative decision table, assign weights to three categories "past, present, future" (e.g., 30%/50%/20%), score sub-items under each category, and finally replace struggles with numbers
• Wheat Ear Theory for mate selection: For mate selection between ages 22-30, spend the first 3 years (37%) observing only to establish a benchmark of the highest score, then immediately choose anyone who exceeds the benchmark in the next 5 years
• Third Option — Two Swords: Choose sharp or good-looking? Restore the goal (going to war or used as decoration), and the answer automatically appears once the goal is determined
• Cognitive Bias — Shopping: Two clothes priced at 399 yuan each, one is originally priced at 399 yuan, the other is originally priced at 3999 yuan with a 90% discount. People think the second one is cheaper—this is the Anchoring Effect

• Facing major life/business decisions and struggling
• Dissatisfied with both options but feeling "must choose one"
• Worried that your judgment is misled by emotions or intuition
• Need to prove the rationality of a decision to others (instead of making arbitrary choices)

• "Torn between choosing A or B"
• "Both are bad but I have to pick one"
• "Help me make a decision"
• "How to choose without regret?"
• "I think this choice is very important"

• vs. structured-thinking: Structured thinking is about "how to break down problems", while scientific decision-making is about "how to make the optimal choice from options"; structured thinking is a prerequisite for decision-making
• vs. systems-thinking: Systems thinking analyzes "why this happens", while scientific decision-making determines "what to do next"

• Write down the core goal you truly want to achieve (not the options themselves)
• Judge whether this problem is worth spending time on decision-making—filter out 80% of trivial matters directly
• If it's a key issue, proceed to the next step
• Completion standard: Can write the core goal in one sentence and confirm "this problem deserves in-depth decision-making"

• List the options you currently face, ask yourself: "Who gave me these options?"
• Return to the core goal, turn the multiple-choice question into a short-answer question: "What else can I do to achieve the goal?"
• Find a third solution that maximizes the interests of relevant parties
• If it involves an irreversible choice, apply the 37% Rule: spend the first 37% of the time observing only to establish a benchmark
• Completion standard: At least produce one new solution beyond the original options, or confirm that a benchmark has been established using the 37% Rule

• Self-check for three major biases: Am I taking risks due to fear of loss (Reflection Effect)? Am I giving up better options for the sake of certainty (Certainty Effect)? Am I influenced by an anchor value (Anchoring Effect)?
• Establish a quantitative table: List evaluation dimensions → assign weights → score each option item by item (0-100)
• Calculate weighted sums and compare the numbers
• Completion standard: Each option has a weighted total score, and the highest score is the optimal rational choice

• Daily low-risk small decisions (what to eat, what to wear)—quantitative decision-making wastes time and energy
• Scenarios requiring rapid response (crisis handling)—no time to go through the four-step process
• Pure subjective aesthetic preference issues

• Over-quantification: Forcing scores on dimensions that should rely on intuition—the numbers seem precise but are actually false
• Weight setting bias: Weight assignment itself reflects preferences; if preferences are influenced by biases, quantification is meaningless
• Analysis paralysis: Still afraid to choose after completing the four steps, falling into an infinite loop

• Lacks a self-check mechanism for "how to determine whether weight assignment is reasonable"; weights themselves are the biggest subjective judgment point
• The 37% Rule assumes that evaluation objects appear randomly, but in reality, people can change the probability distribution through active search

• metacognition-control (prerequisite): Scientific decision-making requires activating "System 2" for slow thinking, and metacognition control is exactly the switch that helps you switch from "brain autopilot" to "rational takeover", which is a prerequisite for rational decision-making.
• mirror-world (prerequisite): The four-step scientific decision-making process is most effective in the "control domain" and "probability domain" of the mirror world. First use the mirror world to judge which domain the event falls into, then decide whether to apply the scientific decision-making process.