Size Is Indicative Of Importance
‘He Took Out Wood to Cook an Egg…’
The Ramban and the Rashba, both Rishonim, were in fact mentor and student. In the chapters of Meseches Shabbos currently studied, the Gemara describes at great length the minimum size requirements of dozens of different objects for which a person would be liable if he carried them on Shabbos. Specks of dust, breadcrumbs and the like, are all negligible; therefore, carrying them does not constitute meleches hotza’ah.
Solids And Liquids
The Pnei Yehoshua (Shabbos 76b) notes an interesting contrast between the minimum requirements of liquids and foods. In regard to liquids, the Gemara dictates different measurements for each liquid. In regard to animal foods, the Gemara distinguishes between different foods according to the requirements of the animals that generally eat each type of food. In regard to human foods, however, the Gemara dictates one standard measurement for them all – k’grogeres, the size of a dried fig.
Halacha l’Moshe Mi’Sinai
The Pnei Yehoshua explains, based on a Gemara in Meseches Eruvin (4b), that the size requirement for human food – k’grogeres – was transmitted to Moshe Rabbeinu on Har Sinai. Hence, we do not apply our own reasoning to determine what size of each different type of food makes one liable for carrying on Shabbos. However, Heaven did not inform Moshe what measurement would make one liable for carrying various types of liquids, animal foods, or other articles. Rather, Heaven gave Moshe, and the Sages who would succeed him, the authority to determine the minimum requirement of each item based on their own understanding of each item’s relative importance.
The Gemara rules that if a piece of food smaller than a dried fig expands to that size, one would be liable for carrying it outside. The Ramban notes an apparent contradiction in Meseches Menachos (54a). The minimum size concerning most mitzvos and aveiros is the size of an olive. If a piece of food is smaller than an olive and then expands to that size, it does not acquire the legal significance of an olive – neither in regard to mitzvos (such as eating matzah) nor in regard to aveiros (such as eating non-kosher meat). Why is the dried fig measurement treated differently than the olive measurement?
The Ramban leaves his question unanswered, confessing that he is unable to find a distinction between hilchos Shabbos (which requires the dried fig measurement) and the other mitzvos and aveiros mentioned in Menachos (which require the olive measurement).
Two Contrasting Measures
In answer to his own rebbe’s question, the Rashba suggests that whereas other mitzvos and aveiros are measured by size, matters concerning hilchos Shabbos are measured by importance. Size is merely an indicator of importance. Thus, if a food item is less than the size of an olive but then is inflated by air pockets inside it, the actual size of the food has not increased. Thus, there is no legal significance to this expansion. It still is unimportant. However, in regard to hilchos Shabbos, we must concede that people view a larger piece of food as more important, even if its increased size is only due to the air pockets inside it.
Perhaps we might explain that the Ramban rejected this answer, based on the Gemara in Eruvin cited above by the Pnei Yehoshua. True, in regard to hotza’ah, most objects are measured by their importance. However, the dried fig measurement for human food is not based on each item’s relative importance. It is rather a fixed measurement which Heaven transmitted to Moshe on Har Sinai. Therefore, there should be no distinction between the olive and dried fig measurements. That’s why the Ramban couldn’t answer his question.