彼亦一是非，此亦一是非bǐ yì yī shì fēi,cǐ yì yī shì fēi

there is reason on both sides; there are no fixed concepts of right and wrong; there is truth in this and also truth in that; this may be right,but the reverse may not be wrong
❍ 增加混乱的倒是有些悲观论者，不施考察，不加批评，但用 “～” 的论调，将一切作者，诋为 “一丘之貉”。这样子，扰乱是永远不会收场的。(鲁迅《准风月谈·中国文坛的悲观》) In fact it is these pessimists who increase the chaos by saying there is reason on both sides,without examining the situation or passing censure,but considering all writers birds of one feather.This is no way to end the chaos.
❍ 至于说： “平心而论，彼一是非，此一是非，原非确论”，则在近来的庄子道友中，简直是鹤立鸡群似的卓见了。(《鲁迅选集》Ⅳ—166） As for his contention that “Strictly speaking,it is not true to say that there are no fixed concepts of right and wrong”，that is really a remarkable statement,quite outstanding for a dis ciple of Zhuang Zi.
❍ 我们如果到庄子里去找词汇，大概不可以过着两句宝贝的教训： “～”，……(《鲁迅选集》Ⅳ—139) Again if we look for phrases in Zhuang Zi,we can probably find this inestimable precept; “There is truth in this and also truth in that.”/此所谓 “～”，你固然不能说没有衣服对，然而你又怎么能说有衣服对呢？(鲁迅《故事新编·起死》124) This is why we say:“This may be right,but the reverse may not be wrong.”You can’t say it is right never to wear clothes; on the other hand can you say it is always right to wear them?

彼亦一是非，此亦一是非bǐyìyīshìfēi,cǐyìyīshìfēi

〔其他〕 指同一事物从不同的角度、不同的目标来衡量。鲁迅《准风月谈·中国文坛的悲观》：“增加混乱的倒是有些悲观论考，不施考察，不加批判，但用‘～，～’的论调，将一切作考，诋为‘一丘之貉’。”
△ 多用于衡量事物方面。

彼亦一是非，此亦一是非

“彼”有它的是和非，“此”也有它的是和非。指是非没有绝对的标准，常随时间、地点、条件的不同而变化。语出《庄子·齐物论》：“是亦彼也，彼亦是也。彼亦一是非，此亦一是非。果且有彼是乎哉？果且无彼是乎哉？”[例] 比年以来，大臣去位，凡其所行之事，所引之人，率皆废而逐之，辈出辈入，相倾相挤，～，至于今未决也。(宋·林季仲《乞进退大臣以礼状》)｜然且～，况其有无疑似微暧难明者乎？(清·朱彝尊《经义考》卷二〇二)
倒作〖此亦一是非，彼亦一是非〗 《续资治通鉴长编·哲宗元祐四年》：“夫天无心而万物覆，地无心而万物载，圣人无心而是非定。夫～也。”