con·tra·dict

• contradict [contradicere, from contra- + dicere 'to say']
  • contra-: acting against sth, or opposite to sth →魂斗罗(Contra). 反恐精英(Counter Strike)将玩家分为“反恐精英”(Counter Terrorists)与“恐怖份子”两队
• dictate [dictare 'to say often, say firmly', from dicere 'to say']]
• edict [edicere 'to give out an official statement'] 法令; 敕令; 公告 =decree
• indict [indicere 'to say publicly or officially', from dicere 'to say'] 控告; 起诉
• interdict [interdicere 'to forbid']
• predict [praedicere 'to say beforehand']
• verdict [ver 'true' + dit 'saying, judgment'] 裁断; 裁决; 裁定

In traditional logic, a contradiction consists of a logical incompatibility or incongruity between two or more propositions. It occurs when the propositions [命题], taken together, yield two conclusions which form the logical, usually opposite inversions of each other. Illustrating a general tendency in applied logic, Aristotle's law of noncontradiction states that "It is impossible that the same thing can at the same time both belong and not belong to the same object and in the same respect."

• congruent [congruere 'to come together, agree']
• The incongruity of something is its strangeness when considered together with other aspects of a situation.

In modern formal logic, the term is mainly used instead for a single proposition, often denoted by the falsum symbol ⊥; a proposition is a contradiction if false can be derived from it, using the rules of the logic. It is a proposition that is unconditionally false (i.e., a self-contradictory proposition). This can be generalized to a collection of propositions, which is then said to "contain" a contradiction.

The falsum "⊥" (Upside down T) is a symbol used in various mathematic disciplines [学科], but throughout them it shares the meaning of "arbitrary contradiction" and "false." Wiktionary further defines falsum as meaning "an untruth, falsehood, fraud, deceit, lie; forgery."

Colloquial usage can label actions or statements as contradicting each other when due (or perceived as due) to presuppositions [assumption] which are contradictory in the logical sense.

Proof by contradiction is used in mathematics to construct proofs.

The scientific method uses contradiction to falsify bad theory.

Contradiction on Graham's Hierarchy of Disagreement:

"call sb names" = "use insulting names for someone", e.g. "The other kids used to call me names, but I tried to ignore them."

六级/考研单词: contradict, terror, dictate, seldom, decree, indict, prohibit, verdict, logic, yield, invert, situate, denote, derive, arbitrary, farther, fraud, forge, usage, mathematics, construct, hierarchy, insult