Targum Pseudo-Jonathan in Rabbinic Literature

Question

The Gemara Megillah (3a) implies that Onkelos translated just the Chumash, whereas Yonattan ben Uzziel translated just Nevi'im:

וא''ר ירמיה ואיתימא רבי חייא בר אבא תרגום של תורה אונקלוס הגר אמרו מפי ר' אליעזר ור' יהושע תרגום של נביאים יונתן בן עוזיאל אמרו מפי חגי זכריה ומלאכי

This would seem to be a decent source for suggesting that the commentary commonly attributed to YbU on the Chumash is mis-attributed.

Do any rabbinic sources state that this work was not authored by YbU?

Do they note the aforementioned inference from Megillah?

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Note: I am not asking about the Targum on Ketuvim (See Ritva in Megillah there who addresses this). Nor am I asking about the authenticity of the work. Nor am I seeking sources that assume that he was the author. I am specifically looking for sources that say he is not the author.

Answer 1

The preface to the Oz Vehadar Mikraos Gedolos brings a few more sources besides the ones @Rish brings. I also found a couple on my own.

Rav Binyomin Musfia in his work מוסף הערוך, in ערך אשן ב, and ערך פתרן and ערך צם says Yonasan Ben Uziel didn't write a Targum on Chumash. He also brings a proof that he didn't, in that Numbers 24:24 says וצים מיד כתים, Targum Yonasan says its קוסטנטיני (Constantinople), which wasn't a city that was build in his time, rather much later.

Rav Menachem Mendel Kasher in Torah Sheleimah Volume 17 (Mishpatim) Miluim 23 in footnote 12 writes it's already become clear that the Tanna Yonasan didn't write the Targum Yonasan, and it's really a version of Targum Yerushalmi. He brings the acronym idea mentioned by Mendelssohn below.

You asked if authorities used the gemarra in Megillah as a basis for rejecting the assumption the Tanna Yonasan authored this Targum. The following three make that very point.

Rav Yaakov Emden in his commentary on the Mishnah called Lechem Shamayim, at the end of Megillah.

The Maharatz Chiyos in his work אמרי בינה, Simman 4 brings a suggestion by Mendelssohn in Nesivos HaShalom, that Chumashim used to write ת"י for Targum Yerushalmi, but became messed up as Targum Yonasan. The text is as follows:

תרגום על התורה אשר נתיחס ליונתן, אינו ממנו כאשר התעוררו החכמים כבר כי ממקומו הוא מוכרע, כי בא מזמן אחרון הרבה מאות שנה, אחר מיתת יונתן, עוד הרי אמרו (מגילה ג ' ע"א) תרגום על התורה אונקלוס הגר אמרו, תרגום נביאים יונתן בן עוזיאל אמרו, ומוכח מזה דדוקא על נביאים בא התרגום מיונתן ולא על התורה, ועיין מהרש"א...וע' מ"ש הרב החכם בעל נתיבות השלם, שהחליט דבע"כ דבכל הדפוסים נפל טעות, שהיה כתוב ת"י בראשי תיבות, וטעו המדפיסים שהוא ר"ת תרגום יונתן

(Edit: I now realize @Rish already mentioned the Maharatz Chiyos, but it's still helpful to know where he writes it and why)

Rav Asher Weiss in Minchas Asher Bamidbar Simman 44 also brings the opinion of the Chida. He writes it's for sure the work of one of the קדמונים and any words he writes that are difficult, צריך ליישבם. In Minchas Asher Vayikra Simman 43 he writes more. He brings the gemarra in Megillah that sounds like Yonasan ben Uziel didn't write a Targum on Torah, but then says it's not necessarily a proof he didn't. He ends up saying like the Ri Chagiz that he didn't author it, and it's really a version of Targum Yerushalmi.

Rav Kasher in Torah Sheleimah Volume 24, his essays on the targumim, in the preface lists a bunch of other sources that all say Targum Yonasan is really a version of Targum Yerushalmi. They are:

Rav Avigdor Kara in his work Sefer Hakaneh 59b (the earliest Rav Kasher found)

Azariah dei Rossi in Meor Einayim Imrei Binah Chapter 9

Rav Yeshaya Pick in his work Minei Targumah, Parshas Kedoshim

Rav Dovid Luria in his preface to Pirkei DeRabbi Eliezer

Answer 2

The Maharsha on your Gemara states that he believes Yonatan ben Uziel did not translate the Torah.

אלא שלא היה יונתן חש לפרש התורה אז מטעמא דלקמן דמפרש' מלתא ולא היה מפרש רק נביאים דאיכא מילי דמסתמן עד שבא אונקלוס ופירש לדורו גם התורה

The Chida (שם הגדולים: תרגומים, pg 33-34 here) discusses the question of the origin of Targum Yonatan, bringing various sources including the aforementioned Maharsha on your Gemara, and determines that the Targum attributed to Yonatan ben Uziel was probably not written by him, based on those sources as well as a claim that there are differences in language between the Aramaic of the Torah Targum attributed to Yonatan ben Uziel and that of his Navi Targum.

וגם שמעתי באמרים להוכיח כן דלשון תרגום מיוחס ליונתן שעל התורה מוכיח שאינו מיונתן ב"ע. דלשונו משונה מתרגום יונתן נביאים.

The Chida there mentions that R' Yaakov Chagiz (in the Korban Mincha, סימן נ"ד) is among those who believe it is incorrectly attributed:

ראיתי בס' קרבן מנחה למהר"י חאגיז סי' נ"ד שכתב דתרגום זה שבידנו על התורה מיונתן אינו ליונתן בן עוזיאל אלא הוא תרגום ירושלמי

According to this book (my source for the locations of the previous quotations), R' Z.H. Chajes also did not believe Yonatan ben Uziel was the author of this Targum.