‘Contrariwise,’ continued Tweedledee, ‘if it was so, it might be; and if it were so, it would be: but as it isn’t it ain’t. That’s logic.’

  • -- Lewis Carroll 刘易斯·卡罗尔

“正好相反,”特威帝接着说,“如果是这样,也许是;如果是这样,那就会是;但既然不是这样,那就不是。这就是逻辑。”