Modus vivendi Modus vivendi Modus vivendi is a Latin phrase that means "mode of living" or “way of life”. It often is used to mean an arrangement or agreement that allows conflicting parties to coexist in peace. In science it is used to describe lifestyles. "Modus" means "mode", "way", "method", or "manner". "Vivendi" means "of living". The phrase is often used to describe informal and temporary arrangements in political affairs. For example, if two sides reach a "modus vivendi" regarding disputed territories, despite political, historical or cultural incompatibilities, an accommodation of their respective differences is established for the sake of contingency. In
Modus tollens is a metalogical symbol meaning that formula_10 is a syntactic consequence of formula_6 and formula_9 in some logical system; or as the statement of a functional tautology or theorem of propositional logic: where formula_1 and formula_2 are propositions expressed in some formal system; or including assumptions: though since the rule does not change the set of assumptions, this is not strictly necessary. More complex rewritings involving "modus tollens" are often seen, for instance in set theory: Also in first-order predicate logic: Strictly speaking these are not instances of "modus tollens", but they may be derived from "modus tollens" using a