来书云：「致知之说，春间再承诲益，已颇知用力，觉得比旧尤为简易。但鄙心则谓与初学言之，还须带『格物』意思，使之知下手处。本来『致知』、『格物』一并下，但在初学未知下手用功，还说与『格物』，方晓得『致知』云云。」
「格物」是「致知」功夫，知得「致知」便已知得「格物」；若是未知「格物」，则是「致知」工夫亦未尝知也。近有一书与友人论此颇悉，今往一通，细观之，当自见矣。
来信说：「致知之说，春天再次承蒙教益，已颇知用力，觉得比旧时尤为简易。但我心里觉得对初学者讲，还须带上『格物』的意思，使他知道下手处。本来『致知』『格物』是一并下的，但初学的人不知下手用功，还是先说『格物』，才晓得『致知』云云。」
「格物」是「致知」的功夫，知道了「致知」便已知道了「格物」；若是不知道「格物」，那就是「致知」的功夫也还不曾知道。近来有一封信与友人论此颇详，现在寄去一通，细看自见。
Your letter says: 'On extension of knowledge, receiving your teaching again this spring, I know how to apply strength and find it simpler than before. But for beginners, I think, one must still add the sense of investigating things, to show them where to begin. Extension and investigation are one dropping, yet beginners not knowing the entry should first be told investigation, and then they grasp extension.'
Investigating things is the work of extending knowledge: know extension and you already know investigation; not knowing investigation, the work of extension is not yet known either. I lately wrote a friend on this at length; I send a copy — study it and you will see.