For every complex problem there is a solution that is neat, plausible and wrong.
Mencken's line is a warning about the relationship between a solution's appeal and its adequacy. The simple answer is easier to state, easier to remember and easier to campaign on, so it wins the competition for attention regardless of whether it fits the problem. The test it implies is practical: if an answer to a genuinely tangled question can be given in one sentence and provokes no objections, that is information about the answer.
In practice
- A policy that fits on a poster is not thereby wrong, and the fact that it fits on a poster is not evidence that it is right.
- A post-mortem that identifies one cause for a failure with eleven contributing conditions has produced something neat.