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# Requisite Variety

# Definition

The principle that effective regulation requires the controlling system to
possess at least as much complexity and adaptability as the system being
controlled, ensuring adequate responsiveness to changing conditions.

## Source Chapter

Book IV, Chapter 5

## Context

While not using the modern term, Smith's arguments about the need for
flexible and responsive economic policies that can adapt to changing
conditions reflect the principle of requisite variety in economic regulation.

## Economic Domain

General Theory

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