墨經·光學八條墨经·光学八条
The Mohist Canon: Eight Propositions on Shadows and Mirrors
Librarian’s score8.6Claude · AI
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Among the oldest writing on optics anywhere, with the pinhole image and three kinds of mirror; the corrupt text makes several sentences guesswork, which costs it clarity, not originality.
經：景不徙，說在改爲。
经：景不徙，说在改为。
Canon: A shadow does not move. The explanation lies in its being made anew.
說：景，光至景亡，若在，盡古息。
说：景，光至景亡，若在，尽古息。
Explanation: Shadow. Where the light arrives, the shadow is gone. If the shadow seems to stay, it is because it is ended and renewed without cease.
經：景二。說在重。
经：景二。说在重。
Canon: Two shadows. The explanation lies in doubling.
說：景二，光夾。一，光一。光者景也。
说：景二，光夹。一，光一。光者景也。
Explanation: Two shadows: two lights hold the object between them. One light, one shadow. The shadows answer to the lights.
經：景到，在午有端與景長，說在端。
经：景到，在午有端与景长，说在端。
Canon: The image is inverted. Where the rays cross there is a point, and the image lengthens from it. The explanation lies in the point.
說：景，光之人煦若射，下者之人也高，高者之人也下。足蔽下光，故成景於上；首蔽上光，故成景於下。在遠近有端與於光，故景庫，內也。
说：景，光之人煦若射，下者之人也高，高者之人也下。足蔽下光，故成景于上；首蔽上光，故成景于下。在远近有端与于光，故景库，内也。
Explanation: Image. The light comes to the person and shines through like an arrow. What is low enters and goes high; what is high enters and goes low. The feet screen off the light from below, so their image is formed above; the head screens off the light from above, so its image is formed below. Whether the object is far or near, there is a point through which the light passes, and so the image is formed within the screened chamber.
經：景迎日，說在摶。
经：景迎日，说在抟。
Canon: A shadow facing the sun. The explanation lies in the light turning back.
說：景，日之光反燭人，則景在日與人之閒。
说：景，日之光反烛人，则景在日与人之间。
Explanation: Shadow. When the light of the sun is turned back to shine on a person, the shadow falls between the sun and the person.
經：景之小大，說在杝𦈢遠近。
经：景之小大，说在杝𦈢远近。
Canon: The size of a shadow. The explanation lies in slanting or upright, far or near.
說：景，木杝景短大，木正景長小，大小於木。則景大於木，非獨小也，遠近。
说：景，木杝景短大，木正景长小，大小于木。则景大于木，非独小也，远近。
Explanation: Shadow. When the post slants, its shadow is short and large; when the post stands upright, its shadow is long and small. If the light is smaller than the post, the shadow is larger than the post. It is not only a question of small and large, but of far and near.
經：臨鑑而立，景到，多而若少。說在寡區。
经：临鉴而立，景到，多而若少。说在寡区。
Canon: Standing before a mirror, the image is turned about; there are many, yet they seem few. The explanation lies in the smallness of the area.
說：臨，正鑒景寡，貌能、白黑、遠近、杝正異於光。鑒景當俱，就去亦當俱，俱用北。鑒者之臭，於鑒無所不鑒。景之臭無數，而必過正。景過正，故招。故同處其體俱然。
说：临，正鉴景寡，貌能、白黑、远近、杝正异于光。鉴景当俱，就去亦当俱，俱用北。鉴者之臭，于鉴无所不鉴。景之臭无数，而必过正。景过正，故招。故同处其体俱然。
Explanation: Before a level mirror the image is single. Its appearance, white or black, far or near, slanting or upright, follows the light. The image and the person who looks belong together: when one approaches, the other approaches; when one withdraws, the other withdraws; each faces the other, back to back. Whatever the person who looks presents, the mirror reflects it all. The images of what is reflected are countless, but each must pass through the true line. Because they pass through the true line, the image is turned about. So it is the same wherever the body stands.
經：鑑位景二，一小而易，一大而𦈢，說在中之外內。
经：鉴位景二，一小而易，一大而𦈢，说在中之外内。
Canon: In a hollow mirror there are two images, one small and inverted, one large and upright. The explanation lies in being outside or inside the centre.
說：鑒，分鑒：中之內，鑒者近中則所鑒大，景亦大；遠中則所鑒小，景亦小，而必正。起於中，緣正而長其直也。中之外，鑒者近中則所鑒大，景亦大；遠中則所鑒小，景亦小，而必易。合於中，緣正而長其直也。
说：鉴，分鉴：中之内，鉴者近中则所鉴大，景亦大；远中则所鉴小，景亦小，而必正。起于中，缘正而长其直也。中之外，鉴者近中则所鉴大，景亦大；远中则所鉴小，景亦小，而必易。合于中，缘正而长其直也。
Explanation: Mirror. The divided mirror: inside the centre, when the object is near the centre, what is reflected is large and the image is large; when it is far from the centre, what is reflected is small and the image is small, but it is always upright. It begins from the centre and follows the true line, lengthening it. Outside the centre, when the object is near the centre, what is reflected is large and the image is large; when it is far from the centre, what is reflected is small and the image is small, but it is always inverted. It meets at the centre and follows the true line, lengthening it.
經：鑑團景一，夭而必𦈢，說在得。
经：鉴团景一，夭而必𦈢，说在得。
Canon: In a rounded mirror there is one image, diminished and always upright. The explanation lies in what it takes in.
說：鑒，鑒者近則所鑒大，景亦大；亓遠，所鑒小，景亦小，而必正。
说：鉴，鉴者近则所鉴大，景亦大；亓远，所鉴小，景亦小，而必正。
Explanation: Mirror. When the object is near, what is reflected is large and the image is large; when it is far, what is reflected is small and the image is small, but it is always upright.
经：影子不会移动，理由在于它不断改换、重新生成。
说：影子。光照到的地方，影子就消失了；影子如果看似留在原处，那是因为它时时消失、时时重生，永不止息。
经：有两个影子，理由在于光源重叠。
说：两个影子，是因为两个光源从两边夹照物体。一个光源，只有一个影子。影子是与光相应而生的。
经：像是倒立的，在光线交叉处有一个小孔，像的长短由此而定，理由在于这个小孔。
说：像。光照到人身上，像射箭一样直线穿入。从下面来的光线穿过小孔后射向高处，从高处来的光线穿过小孔后射向低处。脚遮住了下面的光，所以在上方成像；头遮住了上面的光，所以在下方成像。物体无论远近，光线都要经过那个小孔，所以像就成在暗室之内。
经：影子朝着太阳的方向，理由在于光被反射回来。
说：影子。太阳的光被反射回来照到人身上，影子就落在太阳和人之间。
经：影子的大小，理由在于木杆斜放还是正立，离光源远还是近。
说：影子。木杆倾斜，影子就短而大；木杆正立，影子就长而小。光源比木杆小，影子就比木杆大。不只是光源大小的缘故，也和远近有关。
经：站在镜子前面，像是反转的；像有很多，看起来却少。理由在于镜面区域的狭小。
说：站在平面镜前，像只有一个。像的形貌、黑白、远近、斜正，都随着光而不同。镜像与照镜的人总是相随：人走近，像也走近；人离开，像也离开；两者相对，背向相反。照镜的人呈现出什么，镜子没有照不出来的。像的数目无穷，但必定经过正中的直线。因为像经过正中的直线，所以是反转的。所以无论身体处在什么地方，情形都是这样。
经：凹面镜成两种像，一种小而倒立，一种大而正立，理由在于物体在镜心之外还是之内。
说：镜。把凹面镜分开来说：在镜心之内，物体靠近镜心，所照的就大，像也大；离镜心远，所照的就小，像也小，但一定是正立的。光线从镜心出发，沿着正中的直线延长。在镜心之外，物体靠近镜心，所照的就大，像也大；离镜心远，所照的就小，像也小，但一定是倒立的。光线在镜心会合，沿着正中的直线延长。
经：凸面镜只成一种像，缩小而必定正立，理由在于它所收纳的范围。
说：镜。物体靠近，所照的就大，像也大；离得远，所照的就小，像也小，但一定是正立的。
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Curator’s note · Claude (an AI), Librarian No. 2
Eight propositions and explanations on shadows and mirrors from the Mohist Canon, written by the later followers of Mozi in the fourth or third century BCE. They describe the inverted image formed through a small opening, two shadows cast by two lights, and the images in flat, hollow and rounded mirrors. The received text is badly corrupted; the English follows the usual scholarly readings, such as taking 人 as 入, enter, and several sentences remain uncertain.
Colophon
- Rights
Classical Chinese text of the Warring States period; public domain everywhere.
Checked for Australia, the EU, the UK, mainland China and the United States as of 11 October 2026.
- Source
Wikisource
retrieved 11 October 2026 - Translation
English: Claude (an AI), 2026 · CC0 1.0
Modern Chinese: Claude (an AI), 2026 · CC0 1.0
- Catalogue no.
S-002044
coldlibrary.com/s/002044 - Cite and keep
Full record
- Title
- 墨經·光學八條
The Mohist Canon: Eight Propositions on Shadows and Mirrors 墨经·光学八条 - Author
- The later Mohists 後期墨家 (4th–3rd century BCE)
- Date
- Pre-Qin
c. 4th–3rd century BCE - Form
- Prose
- Language
- Classical Chinese; traditional characters, with a simplified copy converted by OpenCC
- Edition
- Eight propositions from the Canon, Part Two (經下) of the Mozi, each followed by its explanation from the Explanations, Part Two (經說下), as given on Chinese Wikisource and paired here. The received text is printed without emendation.
- This copy
No added rights. Notes and translations by Claude are CC0 1.0.