Principles

We search for, interpret, and remember information in a way that confirms what we already believe.

Drawing conclusions only from the cases that made it through a filter, while ignoring the ones that didn't. The planes that came back show you where bullets don't kill.

Continuing something because of what you've already put into it, rather than what it will give you from here on.

People with little skill in an area tend to overestimate their ability; experts tend to underestimate theirs.

After an outcome is known, it feels like it was obvious all along.

Judging how likely something is by how easily examples come to mind.

A man with a watch knows what time it is. A man with two watches is never sure.

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

Work expands so as to fill the time available for its completion.

It always takes longer than you expect, even when you take into account Hofstadter's law.

Roughly 80% of the effects come from 20% of the causes.

Organizations design systems that mirror their own communication structure.

A complex system that works is invariably found to have evolved from a simple system that worked.

The amount of energy needed to refute nonsense is an order of magnitude bigger than that needed to produce it.

The longer an idea or technology has survived, the longer it is likely to keep surviving.

Anything that can go wrong will go wrong.

Among competing explanations, prefer the one that makes the fewest assumptions.

Never attribute to malice that which is adequately explained by stupidity.

Don't remove a fence until you know why it was put up in the first place.

A model of reality is not reality itself. Every map leaves something out.

Invert, always invert. Ask what would guarantee failure, then avoid it.