Not all scholars in any discipline have equal expertise and not all rabbis have equal authority. Complex or consequential questions must be taken to rabbis with sufficient expertise and experience to answer them properly. This idea is so self-evident that one who ignores it faces potential halakhic ramifications.
R. Meir (Maharam) of Rothenburg, in a responsum published in standard editions of the Mishneh Torah (after Nashim, no. 11), answers the following question. A woman’s husband drowned in a body of water that qualifies as “endless” (mayim she-ein lahem sof). What happens if she remarries?
The law is that since the husband may have survived and resurfaced far away, she may not remarry due to a rabbinic decree. However, if she remarries she need not get divorced (see Shulchan Arukh, Even Ha-Ezer 17:34). In other words, lechatchilah she may not remarry but bedi’eved, after the fact, she may.
Maharam qualifies this. If the rule was really that any such woman who marries may remain married, then this rabbinic decree would be ineffective and meaningless. Rather, the rule must be that if such a woman receives mistaken permission from a rabbi to remarry, she need not divorce her husband. Because they did the right thing by asking a rabbi, they are in a state of bedi’eved. If, however, they failed to ask a rabbi, their intentional disregard places them in a state of lechatchilah and they must divorce. They are not considered accidental sinners in the category of shogeg but intentional sinners in the category of meizid.
Maharam writes that they need to ask a “חכם מורה הוראות בעינן כי רב נחמן ורב שילא בדורם – a scholar who issues rulings like Rav Nachman and Rav Shila in their generations.” In other words, they must ask a rabbi who is sufficiently expert to rule on such a complex question. Anything less renders them negligent, for which they must suffer halakhic consequences.
R. Menachem Mendel Krochmal (Responsa Tzemach Tzedek , no. 44) addresses a similar question. During a time of war and displacement, a widower married his former father-in-law’s widow. Because of the turbulent situation, they could not ask a rabbi but found a learned man who permitted the marriage. R. Krochmal, however, held that such a marriage is lechatchilah forbidden but bedi’eved permitted (see Shulchan Arukh, Even Ha-Ezer 15:24 and commentaries).
Presumably, this couple should be allowed to remain married because they had already entered into their union accidentally, under the category of shogeg. They had even asked a Torah scholar! However, R Krochmal ruled that since they asked a scholar who was not qualified to answer this difficult question, they are considered intentional (meizid) rather than accidental initiators of this situation. If not for the other mitigating factors in this situation, R. Krochmal would have insisted that this couple dissolve their marriage.
The implication of these responsa (quoted in Pischei Teshuvah, Yoreh De’ah 99:5) is both obvious and significant. The title “rabbi” is substantive but does not confer onto its holder unlimited legal authority. Only proficient scholars may rule on any given area. Not only must a rabbi turn away or redirect a question he cannot answer, a questioner must carefully consider whether the rabbi he is asking is sufficiently experienced and expert to respond to his inquiry. Not all rabbis are created equal.