When sefaika derabanan lekula doesn’t apply TB Pesakhim 108 part two

 The Gemara comes to the conclusion since we don’t know whether we should recline for either the first 2 cups of wine or the last 2 cups of wine, we take a stringent position and recline for all 4 cups of wine. “Now that it was stated so, and it was stated so, i.e., there are two conflicting opinions and it cannot be proven which two cups require reclining, both these sets of cups and those require reclining.” (Sefaria.org translation)

This is an interesting position to take because it contradicts a general principle. When the case involves an uncertainty with regard to the legal status of an item prohibited by rabbinic law, the ruling is lenient, sefaika derabanan lekula-סְפֵיקָא דְרַבָּנַן לְקוּלָּא. The mitzvah of drinking 4 cups of wine is only according to the rabbis (דרבנן) and not ordained by the Torah. Since drinking 4 cups of wine is only a rabbinic mitzvah, we would have assumed that wine did not need to be imbibed reclining because that is the more lenient ruling.

The Ran proposes two solutions. First of all, he says that reclining for all 4 cups of wine is not such a great stringency. In other words, what’s the big deal between reclining and not reclining in this case?! Secondly, if we were to hold fast to this ruling of sefaika derabanan lekula, we would not fulfill the obligation of reclining for at least 2 cups of wine. When we would drink the first 2 cups of wine, we would think that the last 2 cups of wine need reclining. When we would drink the last 2 cups of wine, we would think that the first 2 cups of wine the reclining. Consequently, no cup of wine would be drunk reclining! Sefaika derabanan lekula is not operative in cases when the whole concept would be negated.