That that is is that that is not is not is that it it is That that is is that that is not is not is that it it is是一個表達歧義性以及標點符號的重要性的英文短語 這句句子可以通過增加標點符號來分拆成四個句子 That that is is That that is not is not Is that it It is 存在的就是存在的不存在的就是不存在的就是這樣嗎是 還有一個分拆方法 That that is is that that is Not is not Is that it It is 那存在的就是那存在的不是存在的就不是存在就是這樣嗎是 這是一個巴門尼德式的哲學諺語that all that is is and that anything that does not exist does not存在的就是存在的其他所有不存在的就是不存在的這一個短語首先在Brewers Dictionary of Phrase and Fable英语Brewers Dictionary of Phrase and Fable裏出現但在年的短故事獻給阿爾吉儂的花束Flowers for Algernon來源請求變得有名Garylin吉里連在躺在草地上採摘雛菊以及自言自語時注意了它