The reasonable person
From Common law (and its civil-law counterpart)
Basic ideasContract and obligations
What it means
A standard of ordinary care and prudence against which a person's conduct is judged. Common law calls it the reasonable person. Roman-based systems traditionally used the good head of a family.
Why it travels badly
The older civil-law phrase (bon père de famille, diligens pater familias) is a gendered historical image and is now being replaced in many codes by the neutral 'reasonable person', which makes older and newer texts read differently.
How other systems say it
bon père de famille / personne raisonnable
The old formula was replaced by 'raisonnable' in French statutes in the 2010s.
im Verkehr erforderliche Sorgfalt
Section 276 BGB speaks of the care required in dealings, a standard rather than a person.
the reasonable person / the man on the Clapham omnibus
An objective standard applied by the court.
Tip for translators and students
When translating older civil-law texts, 'good head of the household' is accurate but dated; consider 'reasonably prudent person' with a footnote.
Related: Tort and delict, Good faith
Updated October 2026. Spotted a mistake? Tell us.
TheLawToKnow Tools’s glossary is an educational overview of the main differences between legal systems. It is not legal advice.
