Mutatis mutandis is a Medieval Latin phrase meaning "with things changed that should be changed" or "once the necessary changes have been made". It remains unnaturalized in English and is therefore usually italicized in writing. It is used in many countries to acknowledge that a comparison being made requires certain obvious alterations, which are left unstated. It is not to be confused with the similar ceteris paribus, which excludes any changes other than those explicitly mentioned. Mutatis mutandis is still used in law, economics, mathematics, linguistics and philosophy. In particular, in logic, it is encountered when discussing counterfactuals, as a shorthand for all the initial and derived changes which have been previously discussed.