While the term "rule of thumb" is a common idiom, the widely circulated origin story linking it to the legal acceptance of wife-beating with a stick no thicker than a thumb is indeed a myth.
Debunking the Origin Myth
The notion that the phrase "rule of thumb" originates from a historical legal principle permitting domestic violence with a thumb-sized stick is largely unsubstantiated. This origin story gained traction due to an association with English judge Sir Francis Buller in 1782, who was falsely accused of endorsing such a practice. Despite the lack of any evidence supporting Buller's statement or the existence of such a law, the myth persists.
The True Origin and Meaning
The more plausible and widely accepted origin of "rule of thumb" relates to practical and approximate methods of measurement or problem-solving, often based on experience rather than precise calculations. It represents a convenient and readily applicable guideline that is not intended to be strictly accurate or universally reliable.
For example:
- Estimating cooking times: A chef might use a "rule of thumb" to estimate cooking time based on the size of the meat.
- Garden practices: Gardeners might use a "rule of thumb" to determine planting depth for seeds.
- Basic construction: Builders might use a "rule of thumb" to determine the spacing between nails.
These examples illustrate the true essence of the phrase as a general guideline.
Conclusion
The assertion that "rule of thumb" originated from a legal allowance for domestic violence is a myth. The phrase actually refers to a practical, approximate method based on experience.
