to contradict oneself
自相矛盾
A man of the state of Chu (chǔ guó 楚国) had a spear and a shield for sale.
楚国有个卖兵器的人，在市场上卖矛和盾。
He was loud in praises of his shield.“My shield is so strong that nothing can pierce it through.”
为了让人家愿意买他的货，他先举起盾向人们夸口道：“你们看，我的盾是世上最坚固的盾，任何锋利的东西都不能刺穿它。”
He also sang praises of his spear.“My spear is so strong that it can pierce through anything.”
接着又举起他的矛，向人吹嘘说：“你们再看看我的矛，它锋利无比，无坚不摧，无论多么坚硬的盾，都挡不住它，一刺就穿!”
“What would happen，” he was asked， “if your spear is used to pierce your shield?”
人群中有人问道：“如果用你的矛去刺你的盾，结果怎么样?”
It is impossible for an impenetrable shield to coexist with a spear that finds nothing impenetrable.
这世界上一样无坚不摧的东西永远不会与一样什么都能摧毁的东西共存。
“自相矛盾”的英文表达，常用“to contradict oneself”，比如：“你自相矛盾了”就可以说：“You‘re contradicting yourself.”或者“You’ve contradicted yourself.”
曾经有一个英文帖子就讨论过“Can you contradict yourself in one sentence? ”(你能在一句话里面做到自相矛盾吗?)，答案千奇百怪，这里就给大家看两个例子~
1. In the military it‘s， “Hurry up and wait.”(在军队里，有一种说法叫做“Hurry up and wait. ”，英语解释是：“The concept of making every effort to arrive at a location ahead of the appointed time， with the expectation of having to wait upon arrival. ”也就是说不惜一切力量在指定时间之前就到达了目的地，但自己知道到达之后也要一直等到指定的时间。“hurry up(迅速)” 和“wait(等待)”是含有一定相对意义的词，所以就在这么简短的一句话中，就做到了自相矛盾~这句话也被广泛应用在各个场所、各个领域)
2.Yes， I can’t.(这句有很简短啊，同时还达到效果了~“yes(是的)”和“can‘t(不能、不会)”形成了自相矛盾的效果)
