来书云：「闻语学者，乃谓『即物穷理』之说亦是玩物丧志，又取其『厌繁就约』、『涵养本原』数说标示学者，指为晚年定论，此亦恐非。」
朱子所谓「格物」云者，在「即物而穷其理」也。即物穷理是就事事物物上求其所谓定理者也，是以吾心而求理于事事物物之中，析心与理为二矣。夫求理于事事物物者，如求孝之理于其亲之谓也。求孝之理于其亲，则孝之理其果在于吾之心邪？抑果在于亲之身邪？假而果在于亲之身，则亲没之后，吾心遂无孝之理欤？见孺子之入井，必有恻隐之理，是恻隐之理果在于孺子之身欤？抑在于吾心之良知欤？其或不可以从之于井欤？其或可以手而援之欤？是皆所谓理也，是果在于孺子之身欤？抑果出于吾心之良知欤？以是例之，万事万物之理莫不皆然，是可以知析心与理为二之非矣。
夫析心与理而为二，此告子义外之说，孟子之所深辟也。「务外遗内，博而寡要」，吾子既已知之矣，是果何谓而然哉？谓之玩物丧志，尚犹以为不可欤？若鄙人所谓「致知、格物」者，致吾心之良知于事事物物也。吾心之良知，即所谓「天理」也。致吾心良知之「天理」于事事物物，则事事物物皆得其理矣。致吾心之良知者，致知也；事事物物皆得其理者，格物也，是合心与理而为一者也。合心与理而为一，则凡区区前之所云，与朱子晚年之论，皆可以不言而喻矣。
来信说：「听您对学者讲，竟说『即物穷理』之说也是玩物丧志，又取朱子『厌繁就约』『涵养本原』几段话标示学者，指为晚年定论，这恐怕也不对。」
朱子所谓「格物」，是在「即物而穷其理」。即物穷理，是就事事物物上求所谓定理，是以我心到事事物物之中去求理，把心与理分析为二了。在事事物物上求理，比如到父亲身上求孝的理。在父亲身上求孝之理，那孝之理果然在我的心中呢，还是果然在父亲的身上呢？假使果真在父亲身上，那么父亲去世之后，我心中就没有孝之理了吗？见小孩掉进井里，必有恻隐之理，这恻隐之理果然在孩子身上呢，还是在我心的良知呢？或者不可以跟着跳下井去，或者可以伸手援救，这都是所谓理，它果然在孩子身上呢，还是出于我心的良知呢？照此类推，万事万物之理莫不如此，由此可见把心与理分作二的错误了。
把心与理分作二，正是告子「义外」之说，是孟子所深加驳斥的。「务外遗内，博而寡要」，您既然已经知道，又是怎么会到这个地步的呢？说它是玩物丧志，还认为不可以吗？至于我所谓「致知格物」，是把 我心的良知推行到事事物物上。我心的良知就是所谓的天理。把我心良知的天理推行到事事物物，那么事事物物都得到理了。推行我心的良知，就是致知；事事物物都得其理，就是格物。这是心与理合而为一。心与理合而为一，那么我前面所说的一切，与朱子晚年的议论，都可以不言而喻了。
Your letter says: 'I hear you tell learners that even the doctrine of exhausting principle in things is trifling with things and losing the will, and that you cite Zhu Xi's passages on wearying of the manifold for the essential and nourishing the root, marking them his final late-year position — this too seems wrong.'
Zhu Xi's investigating things meant exhausting their principle in the things themselves — seeking a fixed principle in each affair and thing, carrying my mind out into things to find principle: mind and principle split in two. To seek principle in things is like seeking the principle of filial piety upon the parent's body. Is that principle truly in my mind, or upon the parent's body? Were it truly upon the body, then after the parent's death would my mind hold no principle of filial piety? Seeing a child fall into the well, the principle of compassion must stir — is it upon the child's body, or in my mind's innate knowledge? That one may not plunge in after it, or that one may extend a hand — these too are principles: upon the child's body, or out of my mind's innate knowledge? So with all things and affairs: hence the error of splitting mind and principle in two.
That split is Gaozi's rightness-external, deeply condemned by Mencius. That the age pursues the outward, loses the inward, broad without essentials — you already know it; how did it come about? And is 'trifling with things and losing the will' still too strong? My extension-and-investigation means extending my mind's innate knowledge to all affairs and things. That innate knowledge is precisely heavenly principle. Extending its principle to all things, all things receive their principle. Extending the mind's innate knowledge is extending knowledge; all things receiving principle is investigating things: mind and principle joined into one. Joined into one, all I have said, and Zhu Xi's late-year views, need no words to be understood.