What are Principles?
A principle is a foundational decision rule and value orientation — not an operational checklist, but a meta-rule that guides consistent judgment across different situations. Without principles, every decision requires starting from scratch. You’re vulnerable to emotion, pressure, and the loudest voice in the room. With good principles, you have a reliable filter.Principles are your decision firewall. Good principles keep you clear-headed when everything else is chaotic.This category covers 30 core principles, organized into three groups:
- Systems Design Principles: foundational standards for building sustainable systems
- Decision Principles: guides for better choices under high stakes and uncertainty
- Ethics & Collaboration: the foundational norms for working effectively with others
Systems Design Principles
KISS Principle
Keep It Simple — simplicity is the highest design goal
DRY Principle
Don’t Repeat Yourself — every piece of knowledge has a single source of truth
YAGNI Principle
You Aren’t Gonna Need It — don’t build for hypothetical future needs
Single Responsibility Principle
Every module should have one, and only one, reason to change
Separation of Concerns
Different parts of a system should handle different, non-overlapping problems
Principle of Least Astonishment
Systems should behave in the way users expect them to
Fail-Fast Principle
Detect and surface failures early to reduce downstream cost
Iterate and Improve
Ship small, learn fast — never aim for perfection in the first pass
MECE Principle
Mutually Exclusive and Collectively Exhaustive — no gaps, no overlaps in analysis
Decision Principles
Pareto Principle
Focus on the 20% of actions that generate 80% of the results
Skin in the Game
Those who bear the consequences of decisions make better decisions
Via Negativa
Improvement often comes from removing the bad, not adding more good
Reversibility Principle
Prefer decisions that are easy to undo over those that are not
Minimax Principle
Minimize the maximum possible loss
Precautionary Principle
When facing significant uncertainty and high stakes, act cautiously first
Principle of Least Effort
Humans naturally gravitate toward the path of least energy expenditure
Eisenhower Principle
What’s important is rarely urgent; what’s urgent is rarely important
Drucker's Effectiveness Principle
Efficiency is doing things right; effectiveness is doing the right things
Ethics & Collaboration
Principle of Charity
Engage with the strongest version of an opposing argument before critiquing it
Antifragility Principle
Design systems to benefit from disorder, not merely survive it
Subsidiarity Principle
Decisions should be made at the lowest effective level
Proportionality Principle
Responses should be proportionate to the situation
Transparency Principle
Open and clear communication builds trust
Veil of Ignorance
Design rules without knowing your own position in the system
Reciprocity Principle
Treat others as they treat you; mirror their behavior
Parsimony Principle
Among competing hypotheses, prefer the one with fewest assumptions
Radical Candor
Care personally + challenge directly — the antidote to ruinous empathy
Chatham House Rule
Information may be shared freely; the source must remain confidential
80/20 Communication
Listen 80% of the time; speak 20%