# Philosophy
All Philosophy notes →# Productivity
All Productivity notes →Expected Value
Weighing a decision by probability-weighted outcomes rather than gut feel or the most vivid scenario alone.
First Principles Thinking
Reasoning up from fundamentals instead of by analogy to what's already been done — slower, and the only way to beat a locally-optimized status quo.
Opportunity Cost
What a choice actually costs is the next-best option it forecloses, not just the resources it visibly consumes.
2 — Reversible vs Irreversible Decisions
The one-way-door / two-way-door distinction — why irreversible decisions deserve deliberate slowness and reversible ones deserve speed, and conflating the two wastes both.
3 — Avoiding Cognitive Biases
The recurring judgment errors most likely to distort an engineering or career decision — see Philosophy for the full bias catalog this chapter draws on.
4 — Personal Decision Journals
Pre- and post-decision review, graded on process not outcome.