“And it is incomplete”
The Koren notes:
“The following expression: It is incomplete, is essentially an exegetical tool, i.e. added words to clarify the statements of a mishna or a baraita. It should be readas if the added words appear in parentheses. No matter how the mishna is explained, in its present form it remains problematic…”
It is a curious phrase which seeks to correct the text to make it ‘work’. One interesting approach, is that of David Weiss Halivni in his challenging book Revelation Restored. He uses it to prove that the texts, even though they are divine, have changed over the course of history.
I found this interesting discussion on the dafyomi.co.il website on this topic. I have edited it and added to it slightly.
“(a) In order to answer a question posed from a mishnah or baraita, the Talmud will sometimes explain that we have not understood the mishnah or baraita correctly. The Talmud will say “Chisurei Mechsera v’Hachi ka’Tani” — “Words are missing, and it should be read as follows” — and then add words to the mishnah or baraita which allow it to be read differently, thereby answering the question.
(b) The Yad Malachi (Kelalei ha’Ches, #284) writes that the Talmud will sometimes use “Chisurei Mechsera” to change the original understanding of the mishnah or baraita to one that expresses the opposite ruling. He then quotes the Halichot Olam (2:2) as stating that the Talmud will not go that far, but will rather add to or adjust the original explanation of the mishnah. The Yad Malachi cites the Talmud in Sanhedrin (12b), however, as proof of his opinion.
(c) How are we to understand that the Tana seemingly forgot to include such integral information? The Vilna Ga’on (end of Divrei Eliyahu, section entitled “Kelalim”) explains that the use of “Chisurei Mechsera” does not reject the original reading of the baraita. The original reading may be read to mean what the Gemara understands in its final explanation, or it may be teaching a different point altogether (Rabbeinu Bachya writes similarly in his commentary to Shmot 34:27). The Beit Yosef (in “Kelalei d’Gemara”, Halichot Olam 2:41) explains that these teachings were originally given over in this fashion. Rebbi, who edited much of the mishnah, recorded them in the mishnah as they were, expecting those who learned them to fill in the “blanks” on their own. The TIFERES YISRAEL (Boaz to Erchin 4:1) explains that a special tune was utilized when learning mishnayot and baraita to help one commit them to memory (a method used even today in some schools in Israel). The Tana would therefore use wording that fit with the tune even if it rendered the meaning less clear. The Tiferet Yisrael explains that the Tana knew that the true explanation would be apparent to anyone who studied the topic well, as evidenced by that which the Talmud is able to arrive at the proper understanding. (This explanation would appear to be at odds with the explanation of the Vilna Ga’on above)
This may also reflect the fact that the redactor of the mishna was resisting writing down the oral tradition and wanted to keep some aspect of the oral learning by writing certain mishnayot in this form. (Apparently this was the view of Rav Hutner but I do not have a source for this)
(d) The Talmud will sometimes correct the wording of a mishnah or baraita with the word “Teni …” (“teach”) or “Eima …” (“say”). Many Rishonim (e.g., Ran to Nedarim 46a) explain that these terms are used to explain the Tana’s statement, as opposed to amending it. Similarly, the Talmud will sometimes answer a question by insisting that the mishnah or baraita taught its ruling wherein the person involved verbally expressed a certain qualification. In such situations the Talmud will explain, “b’Omer …” (“in a case where he said …”). Here too, many Rishonim explain that the Talmud means that even if he did not actually express such a qualification, it is as if he did (e.g., Tosfot to Yevamot 25b DH b’Omer).