Mental Models for Engineers

First Principles Thinking

Aristotle / Elon Musk

Strip a problem to its fundamental truths and reason up from there — the antidote to reasoning by analogy.

Second-Order Thinking

Howard Marks

Think past the immediate effect to the second and third-order consequences.

Feedback Loops

Norbert Wiener / Jay Forrester

Outputs feed back as inputs, creating either amplifying or stabilizing dynamics.

Inversion

Carl Jacobi / Charlie Munger

Think backwards: instead of asking how to succeed, ask what guarantees failure — then avoid it.

Redundancy

Redundancy is duplicate capacity or parallel paths so that if one element fails, the system can still function. It is a hedge against failure: you pay a cost (extra components,...

Margin of Safety

Benjamin Graham

Buy below intrinsic value to protect against errors and the unforeseen.

Occam's Razor

Among competing explanations, prefer the simplest one.

Map vs Territory

Alfred Korzybski

Models are not reality; confusing the two leads to systematic errors.

Goodhart's Law

Charles Goodhart

When a measure becomes a target, it ceases to be a good measure.

Tight Coupling

Charles Perrow

Tight coupling means components in a system depend on each other in rigid, time-sensitive ways. When one part fails or lags, the rest cannot adapt; failure propagates quickly and...

Chain Reaction

A chain reaction is a sequence in which each step triggers the next. One event causes another, which causes another; the reaction propagates. In nuclear physics, a neutron hits a...

Bottlenecks

Eliyahu Goldratt

In 1984, an Israeli physicist named Eliyahu Goldratt published a business novel called The Goal. The protagonist, Alex Rogo, manages a failing manufacturing plant. His mentor,...

Leverage (Systems)

Donella Meadows

Small shifts at the right point produce outsized systemic changes.

Compounding

Einstein

Exponential growth from consistent small gains over long time horizons.

Activation Energy

Reactions do not start the instant ingredients touch. They need a minimum energy input — activation energy — to overcome the barrier between initial and final state. In chemistry,...

OODA Loop

John Boyd

Cycle through observe-orient-decide-act faster than competitors.

Hanlon's Razor

Robert J. Hanlon

Never attribute to malice that which is adequately explained by incompetence or ignorance. Most bad outcomes come from stupidity, not conspiracy — and assuming malice causes you to misdiagnose the problem.

Black Swan Theory

Nassim Nicholas Taleb

Rare, unpredictable events with extreme impact shape history.

Antifragility

Nassim Nicholas Taleb

Some systems gain from disorder — growing stronger from shocks.

Skin in the Game

Nassim Nicholas Taleb

Decision-makers must bear consequences to align incentives.