Short Answer: Most poskim rule that a child cannot disagree or contradict a parent, regardless of whether the discussion is about Torah/halachah or other topics. However, there is room to be lenient if the child disagrees with the parent (i) not in the parent’s presence, (ii) with the parent’s permission, or (iii) in a questioning manner instead of a disagreeing or objecting manner.
I. The Source
The Gemara in Kiddushin (31b) lists ways that a child should “fear” a parent, including not contradicting or confirming the words of a parent. This law is codified in the Shulchan Aruch (Yoreh Dei’ah 240:2). From the language of the Gemara and the Shulchan Aruch, it is unclear in what context it is forbidden to contradict the parent.
II. The Context
Rashi (ibid), however, comments on the prohibition of confirming the words of a parent, that the child cannot confirm a parent’s words of when the parent is discussing “halachah” with another person. The sefer Yasher Hori (siman 16) infers from here that the simple understanding is that Rashi limits the prohibition of confirming or contradicting a parent to the context of words of Torah or halachah. Moreover, the sefer L’maan Yaarichun Yamecha (siman 9) cites the Tzafnas Paanei’ach who explains that Yosef was permitted to contradict Yaakov by the brachos to Menashe and Ephraim because this was not in the context of learning Torah/halachah.
Nevertheless, the Chayei Adam (67:8) applies the prohibition to words of Torah/halachah and to any other topic. Similarly, the Aruch HaShulchan (Yoreh Dei’ah 240:13) queries whether this prohibition applies even to other topics, and concludes that if a child cannot contradict a parent for Torah/halachah topics, surely the child is prohibited to contradict a parent for other topics, as well.
Indeed, the sefer Yasher Hori (ibid) cites Rabbeinu Yonah that a child cannot contradict the words of a father or mother, and thus proves that this prohibition must also apply to non-Torah topics that are likely discussed by the mother.
On the other hand, the Be’er Sheva (Sanhedrin 110a) [cited as well in the sefer Yasher Hori] argues on Rashi and the Shulchan Aruch. He notes that the Gemara in Kiddushin praises the case where a father and son learn with intensity as chavrusos with each other that they become “enemies” with each other. This Gemara implies that there is no problem with a child contradicting his father in the context of learning Torah. Thus, the Be’er Sheva understands that it is only prohibited to argue with a parent about non-Torah/halachah topics.
Notably, the sefer Ateres Shmuel (Kiddushin, siman 9) cites the Atzmos Yosef who appears to defend Rashi from the proof of the Be’er Sheva. Surely a child can argue with a parent in order to get to the bottom of the Torah/halachah issue they are debating. However, if a father rules definitively that something is asur or mutar, a child cannot contradict him.
III. Behind a Parent’s Back
Can a child contradict a parent behind the parent’s back? In other words, can a child disagree with a parent’s opinion and express a contrary opinion to other people where the parent is not part of that particular discussion?
The Shulchan Aruch (ibid), when codifying this halachah, writes that a child should not contradict or confirm the words of a parent “in front of him.” This is based on the words of the Rambam, who writes similar language by the law of not contradicting a rebbe. The Taz (Yoreh Dei’ah, ibid) thus infers from this language that it is permitted to contradict a parent behind his back (i.e., not in his presence). Similarly, the Vilna Gaon (ibid) agrees with this inference and proves that it is permitted to contradict a parent not in his presence, because many great Amora’im disagreed with their father in the Gemara, presumably not in the father’s presence.
On the other hand, the Shach (ibid), as well as the Drishah, note that the language of the Tur/Shulchan Aruch appears to imply that specifically with respect to confirming a parent’s words, the prohibition only applies in front of the parent. Indeed, the phrase “in front of the parent” follows directly after the words “confirm the parent’s words.” However, with respect to contradicting a parent, the Tur/Shulchan Aruch do not explicitly limit the prohibition to a case where it is in the parent’s presence.
The Aruch HaShulchan (ibid) appears to rule like the Taz, and allows a child to disagree with a parent, as long as the child does not share this disagreement with the parent. The sefer Yasher Hori (ibid) notes that even though the Ben Ish Chai appears to rule stringently like the Shach, the general ruling is like the Taz. However, the sefer Yasher Hori (ibid) is unsure if the leniency of the Taz extends even to other topics or just to arguing with a parent about Torah/halachah, as the proof that Amora’im argued with their father not in his presence is only in the context of Torah/halachah.
IV. Other Leniencies
The sefer P’sakim U’T’shuvos (240:7) cites the ruling of the Chazon Ish and the Sheivet HaLevi that a child can argue with a parent as long as the child raises his objection as a “suggestion” or “possible thought” and not as an outright objection or disagreement.
Likewise, the Aruch HaShulchan (ibid) writes that if a parent asks a child for his opinion, the child may disagree with the parent, even to the parent’s face and even a complete disagreement.
Next Week’s Topic: Is it ever permitted for a child to say the name of his parent?