实践是检验真理的唯一标准
shí​jiàn​shì​jiǎn​yàn​zhēn​lǐ​de​wéi​yī​biāo​zhǔn

practice is the sole criterion for testing truth

实践是检验真理的唯一标准 實踐是檢驗真理的唯一標準 shí​jiàn​shì​jiǎn​yàn​zhēn​lǐ​de​wéi​yī​biāo​zhǔn
practice is the sole criterion for testing truth
A political slogan from 1978, central to the reform period, stating that actual practice is the only way to determine if a theory is true.