deductive system
61Modal logic — is a type of formal logic that extends classical propositional and predicate logic to include operators expressing modality. Modals words that express modalities qualify a statement. For example, the statement John is happy might be qualified by… …
62Monadic predicate calculus — In logic, the monadic predicate calculus is the fragment of predicate calculus in which all predicate letters are monadic (that is, they take only one argument), and there are no function letters. All atomic formulae have the form P(x), where P… …
63Undecidable problem — In computability theory and computational complexity theory, an undecidable problem is a decision problem for which it is impossible to construct an algorithm that leads to a yes or no answer the problem is not decidable.A decision problem is any …
64Classical logic — identifies a class of formal logics that have been most intensively studied and most widely used. The class is sometimes called standard logic as well.[1][2] They are characterised by a number of properties:[3] Law of the excluded middle and… …
65Critical thinking — is the process or method of thinking that questions assumptions. It is a way of deciding whether a claim is true, false, or sometimes true and sometimes false, or partly true and partly false. The origins of critical thinking can be traced in… …
66Logical positivism — (also known as logical empiricism, scientific philosophy, and neo positivism) is a philosophy that combines empiricism the idea that observational evidence is indispensable for knowledge with a version of rationalism incorporating mathematical… …
67Alfred Tarski — Infobox scientist name = Alfred Tarski caption = birth date = birth date|1901|01|14 birth place = Warsaw, Poland (under Russian rule at the time) death date = death date|1983|10|26 death place = Berkeley, California fields = Mathematics, logic,… …
68Non-monotonic logic — A non monotonic logic is a formal logic whose consequence relation is not monotonic. Most studied formal logics have a monotonic consequence relation, meaning that adding a formula to a theory never produces a reduction of its set of consequences …
69Complete partial order — In mathematics, directed complete partial orders and ω complete partial orders (abbreviated to dcpo, ωcpo or sometimes just cpo) are special classes of partially ordered sets, characterized by particular completeness properties. Complete partial… …
70Computability logic — Introduced by Giorgi Japaridze in 2003, computability logic is a research programme and mathematical framework for redeveloping logic as a systematic formal theory of computability, as opposed to classical logic which is a formal theory of truth …
