中文 / C1
自相矛盾
楚国有个出售盾牌和长矛的人。他夸耀盾牌的坚固，声称：「我的盾牌，没有任何东西能够刺穿。」随后又转而称赞长矛的锋利，说：「我的长矛，没有任何东西不能刺穿。」
有人听了，便问：「如果用你的矛，去刺你的盾，又会怎样？」
面对这个问题，卖武器的人无言以对。
盾和矛本来各有用途，一件用于防护，一件用于攻击。问题不在于它们能否一同出售，而在于他对二者作出了互不相容的保证。盾不仅被说成坚固，而且被说成绝对无法刺穿；矛也不仅被说成锋利，而且被说成绝对无所不穿。
听者只用一个假设，把这两项保证放在一起检验，它们之间的冲突便显露出来：矛若刺穿了盾，盾的保证就不成立；矛若刺不穿，矛的保证就不成立。
因此，「任何东西都刺不穿的盾」与「任何东西都能刺穿的矛」，不可能同时成立。
English summary · includes the ending
A man from the ancient state of Chu sells shields and spears. To praise his shield, he claims that nothing can pierce it. He then praises his spear, saying that it can pierce absolutely anything.
Someone asks what would happen if he used his own spear against his own shield. The seller cannot answer. The two claims sound impressive separately, but they cannot both be true when the weapons are tested against each other.
If the spear pierces the shield, the shield is not impossible to pierce. If the shield stops the spear, the spear cannot pierce everything. Either result would disprove one of his promises.
The story ends with the seller unable to resolve this problem. No actual test takes place. A single question is enough to reveal the conflict between his two statements, which is the point behind the familiar Chinese expression for contradicting oneself.
Adapted for Lejrbål from the credited source.
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