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Computing (FOLDOC) dictionary (also found in English - Vietnamese, English - English (Wordnet), )
logic
1. philosophy, mathematics A branch of philosophy and
mathematics that deals with the formal principles, methods and
criteria of validity of inference, reasoning and
Logic is concerned with what is true and how we can know
whether something is true. This involves the formalisation of
logical arguments and proofs in terms of symbols
representing propositions and logical connectives. The
meanings of these logical connectives are expressed by a set
of rules which are assumed to be self-evident.
Boolean algebra deals with the basic operations of truth
values: AND, OR, NOT and combinations thereof. Predicatelogic extends this with existential and universal
quantifiers and symbols standing for predicates which may
depend on variables. The rules of natural deduction
describe how we may proceed from valid premises to valid
conclusions, where the premises and conclusions are
expressions in predicate logic.
Symbolic logic uses a meta-language concerned with truth,
which may or may not have a corresponding expression in the
world of objects called existance. In symbolic logic,
arguments and proofs are made in terms of symbols
representing propositions and logical connectives. The
meanings of these begin with a set of rules or primitives
which are assumed to be self-evident. Fortunately, even from
vague primitives, functions can be defined with precise
meaning.
Boolean logic deals with the basic operations of truthvalues: AND, OR, NOT and combinations thereof. Predicatelogic extends this with existential quantifiers and
ranging over finite sets; the predicate itself takes on
only the values true and false. Deduction describes how we
may proceed from valid premises to valid conclusions, where
these are expressions in predicate logic.
Carnap used the phrase "rational reconstruction" to describe
the logical analysis of thought. Thus logic is less concerned
with how thought does proceed, which is considered the realm
of psychology, and more with how it should proceed to discover
truth. It is the touchstone of the results of thinking, but
neither its regulator nor a motive for its practice.