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发帖数: 10518 | 1 读来读去，不知道为什么create一个wiki account ,, 我想我是走火入魔了。the
parsimony law 说，一切简单，....
This article uses forms of logical notation. For a concise description of
the symbols used in this notation, see List of logic symbols.
In classical logic, the law of non-contradiction (LNC) (or the law of
contradiction (PM) or the principle of non-contradiction (PNC), or the
principle of contradiction) is the second of the three classic laws of
thought. It states that contradictory statements cannot both be true in the
same sense at the same time, e.g. the two propositions "A is B" and "A is
not B" are mutually exclusive.
The principle was stated as a theorem of propositional logic by Russell and
Whitehead in Principia Mathematica as:
3
24
p
p
[1]
The law of non-contradiction, along with its complement, the law of excluded
middle (the third of the three classic laws of thought), are correlates of
the law of identity (the first of the three laws). Because the law of
identity partitions its logical Universe into exactly two parts, it creates
a dichotomy wherein the two parts are "mutually exclusive" and "jointly
exhaustive". The law of non-contradiction is merely an expression of the
mutually exclusive aspect of that dichotomy, and the law of excluded middle,
an expression of its jointly exhaustive aspect. |
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