Article · Wikipedia archive · Last revised Jun 5, 2026

Reasonableness

The concept of reasonableness has two related meanings in law and political theory:As a legal norm, it is used "for the assessment of such matters as actions, decisions, and persons, rules and institutions, [and] also arguments and judgments." As a regulative idea, it "requires... that all factors that might be relevant in answering a practical question be considered and... that they be assembled in a correct relation to each other in order to justify [a judgement]."

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The concept of reasonableness has two related meanings in law and political theory:

  1. As a legal norm, it is used "for the assessment of such matters as actions, decisions, and persons, rules and institutions, [and] also arguments and judgments."1
  2. As a regulative idea, it "requires... that all factors that might be relevant in answering a practical question be considered and... that they be assembled in a correct relation to each other in order to justify [a judgement]."1

Reasonableness should not be conflated with rationality.1

Political theory

Reasonableness has been discussed by political thinkers such as John Rawls (in his 1993 Political Liberalism),231 T. M. Scanlon,2 Brian Barry2 and Georg Henrik von Wright.1

Law

The notion of "reasonableness" is omnipresent in European law, and has also affected "international treaties and general customs".4 Examples of its use can be found in canon and medieval law, suggesting roots going back to Ancient Rome.4

Standards and doctrines

Standards and doctrines requiring reasonableness include:

Constitutional and administrative law

In constitutional and administrative law, reasonableness is a lens through which courts examine the constitutionality or lawfulness of legislation and regulation.121314 According to Paul Craig, it is "concerned with review of the weight and balance accorded by the primary decision-maker to factors that have been or can be deemed relevant in pursuit of a prima facie allowable purpose".15

Common law

Examples of reasonableness standards in common law jurisdictions include:

Mixed jurisdictions

Reasonability

Reasonability is a legal term. The scale of reasonability represents a quintessential element of modern judicial systems and is particularly important in the context of international disputes and conflicts of laws issues. The concept is founded on the notion that all parties should be held to a reasonable standard of conduct and has become embedded in a number of international conventions such as the UNIDROIT principles17 and the CISG.18

The concept of reasonability is applicable to Roman law.19

See also

See also

References

References

  1. Bongiovanni, Giorgio, ed. (2009). Reasonableness and law. Law and philosophy library. Dordrecht Heidelberg: Springer. ISBN 978-1-4020-8499-7.
  2. Moore, Margaret (1996). "On Reasonableness". Journal of Applied Philosophy. 13 (2): 167–178. doi:10.1111/j.1468-5930.1996.tb00159.x. ISSN 0264-3758.
  3. Boettcher, James W. (2004). "What is reasonableness?". Philosophy & Social Criticism. 30 (5–6): 597–621. doi:10.1177/0191453704045756. ISSN 0191-4537. S2CID 146271626.
  4. Zorzetto, Silvia (2015). "Reasonableness". Italian Law Journal. 1: 107.
  5. Thomas Johnson Michie. "Reasonable-Reasonably". Garland and McGehee (eds). The American and English Encyclopaedia of Law. Second Edition. Edward Thompson Company. 1903. Volume 23. Pages 946 and 947
  6. Garland and McGehee (eds). "Reasonable Care". The American and English Encyclopaedia of Law. Second Edition. Edward Thompson Company. 1903. Volume 23. Pages Page 947.
  7. Wood Renton and Robertson (eds). Encyclopaedia of the Laws of England. 2nd Edition. 1908. vol 12. p 378.
  8. Garland and McGehee (eds). "Reasonable Diligence". The American and English Encyclopaedia of Law. Second Edition. Edward Thompson Company. 1903. Volume 23. Pages Page 947.
  9. Alexander Brown, A Theory of Legitimate Expectations for Public Administration, Oxford University Press, 2017, p 4.
  10. Garland and McGehee (eds). "Reasonable Skill". The American and English Encyclopaedia of Law. Second Edition. Edward Thompson Company. 1903. Volume 23. Pages Page 971.
  11. Thomas Johnson Michie. "Reasonable Time". Garland and McGehee (eds). The American and English Encyclopaedia of Law. Second Edition. Edward Thompson Company. 1903. Volume 23. Pages Page 971.
  12. "5.3 Reasonableness". International Commission of Jurists. 21 December 2020. Retrieved 2023-07-13.
  13. Zaring, David (2011). "Rule by Reasonableness" (PDF). Administrative Law Review. 63: 525.
  14. Garrett, Brandon L. (2017). "Constitutional Reasonableness". Minnesota Law Review. 102: 61.
  15. Craig, Paul (2013-01-01). "The Nature of Reasonableness Review" (PDF). Current Legal Problems. 66 (1): 131–167. doi:10.1093/clp/cut010. ISSN 0070-1998.
  16. Knight, Cjs (2008). "Reasonableness Transformed (in Canada)". Judicial Review. 13 (4): 214–218. doi:10.1080/10854681.2008.11426572. ISSN 1085-4681. S2CID 158748576.
  17. Teramura. "Demonstrating reasonableness". Ex Aequo et Bono as a Response to the ‘Over-Judicialisation’ of International Commercial Arbitration. 2020.
  18. Article 8 United Nations Convention on Contracts for the International Sale of Goods
  19. Frier, "Case 98: Reasonability", A Casebook on the Roman Law of Contracts, OUP, 2021, p 223. María José Falcón y Tella, Case Law in Roman, Anglosaxon and Continental Law, 2011, pp 138 to 140.
Further reading

Further reading

Books

  • Bongiovanni, Giorgio; Sartor, Giovanni; Valentini, Chiara (2009). Reasonableness and law. Law and philosophy library. Dordrecht New York: Springer. ISBN 978-1-4020-8500-0.
  • Hevia, Martín (2013). Reasonableness and responsibility: a theory of contract law. Law and philosophy library. Dordrecht: Springer. ISBN 978-94-007-4604-6.
  • Vadi, Valentina (2018). Proportionality, reasonableness and standards of review in international investment law and arbitration. Elgar international investment law. Cheltenham, UK Northampton, MA, USA: Edward Elgar Publishing. ISBN 978-1-78536-858-5.
  • Volpi, Franco, ed. (2003). Reasonableness and interpretation. Ars interpretandi. Münster: LIT Verlag Münster. ISBN 978-3-8258-6638-9.
  • Young, Shaun, ed. (2014). Reasonableness in Liberal Political Philosophy. Taylor & Francis. ISBN 9781317983750.
  • Dindjer, Hasan (2020). A theory of reasonableness in administrative law (Ph.D. thesis). University of Oxford.

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