mutatis mutandis

Definition of mutatis mutandis

Etymology

Latin mutatis mutandis (“those things having been changed which were to be changed”); both words are from Latin mutō (“(I) change”). Mutatis is the ablative plural of the perfect passive participle, and mutandis is the ablative plural of the future passive participle or gerundive.

Adverb

mutatis mutandis

1. Having changed what needed to be changed.
   
   * 1962: Norman Malcolm; Dreaming; chapter ten: “Application to Other Mental Phenomena”, page 48{1}; chapter fifteen: “Continuity between Dreams and Waking Life”, page 100{2}; chapter seventeen: “The Principle of Coherence”, page 110{3} (1977 paperback reprint; Routledge & Kegan Paul; ISBN 0�'7100�'3836�'4 (c), 0�'7100�'8434�'X (p))
   {1} The above reasoning yields an identical result when applied, mutatis mutandis, to illusions or hallucinations or sensory impressions, or to any other psychological events, with the sole exception of dreams.
   {2} Similar considerations apply, mutatis mutandis, to the example of nightmare imagined by Brown.
   {3} In Chapter 10 it was shown that the proof that making a judgment while asleep is an unintelligible notion applies, mutatis mutandis, to all other mental acts and to all mental passivities, and indeed to everything that we should wish to call ‘mental', except dreaming.

Usage notes

• Mutatis mutandis is used to draw the reader's attention to the differences between a statement and a similar but different earlier statement.
• As a foreign phrase, mutatis mutandis is properly italicized when used in English.

Further reading

Mutatis mutandis is a Latin phrase meaning "by changing those things which need to be changed" or more simply "the necessary changes having been made".

The phrase carries the connotation that the reader should pay attention to the corresponding differences between the current statement and a previous one, although they are analogous. This term is used frequently in economics, philosophy and in law, to parameterize a statement with a new term, or note the application of an implied, mutually understood set of changes. The phrase is also used in the study of counter-factuals, wherein the requisite change in the factual basis of the past is made and the resulting causalities are followed.