Uktzin, Chapter 3, Mishnah 6. This mishnah takes up a question that runs through much of our masechta: what qualifies as ochel, food, for the purposes of halachah? Here the question is asked about a whole family of items that nobody would sit down and eat by themselves, yet which are constantly present on the table: spices.
The mishnah lists them one by one. "Hakosht" is costus, one of the spices that was used in the ketores of the Beis Hamikdash. "Vehachamas" is identified by some as amomum, while others explain it as ginger. "Veroshei besomim" refers to the roots and heads of various fragrant spice plants. "Hatiav vehachiltis" are two more powerfully sharp spices. "Vehapilpelin" are peppers, and "vechalos charia" are pressed cakes formed out of saffron.
What all of these share is a single feature: they exist in order to improve something else. A person does not eat costus or chiltis or a saffron cake as a meal. He adds them to his food so that the food should taste better. So do they carry the halachic status of food, or are they merely an accessory to food?
The position of Rebbi Akiva
The Tanna Kamma, who is Rebbi Akiva, rules "nilkachin bechesef ma'aser", that these spices may be purchased with maaser sheini money.
To appreciate this ruling, recall the halachah of maaser sheini. A person is obligated to bring his maaser sheini produce up to Yerushalayim and consume it there. If transporting the produce itself is too burdensome for him, the Torah allows him to redeem it onto money, and then to take that money with him to Yerushalayim. There the Torah instructs him, "venasata hakesef bechol asher te'aveh nafshecha", that he may spend the money on whatever he desires, and the pasuk goes on to spell out the categories: "babakar uvatzon", cattle and sheep, animals meant for eating, "uvayayin uvashechar", wine and other drink. From this listing Chazal derive that only items of eating and drinking may be bought with maaser sheini money.
Rebbi Akiva therefore is telling us something significant. Even though these spices are never eaten in their own right, and serve only to enhance other foods, they nevertheless possess the halachic status of ochel, and one may spend maaser sheini money on them.
But Rebbi Akiva does not carry that status all the way. He continues, "ve'einan mitam'in tumas ochlin", that these spices are not susceptible to the tumah of foods. Since they are not, in the end, a food that stands on its own, they remain outside the framework of tumas ochlin. So concludes the mishnah, "divrei Rebbi Akiva".
The challenge of Rebbi Yochanan ben Nuri
Rebbi Yochanan ben Nuri objects to this two sided ruling, and he frames his objection as a "mah nafshach", a challenge from either side of the question.
His first thrust runs as follows. "Im nilkachin bechesef ma'aser": granted that a man may redeem his maaser sheini onto these spices, we have thereby classified them as food. If so, asks Rebbi Yochanan ben Nuri, "mipnei mah", on what grounds do we shut them out of the halachos of tumah that attach to foods?
And if you wish to answer from the other direction, "ve'im einan mitam'in tumas ochlin", that they are indeed not real food and therefore stand outside the laws of tumas ochlin, then the conclusion should follow consistently: "af hein lo yilakchu bechesef ma'aser", they should equally not be purchasable with maaser sheini money.
Rebbi Yochanan ben Nuri demands a single definition. Either these spices are food or they are not, and whichever way we decide, both halachos should follow together. Rebbi Akiva, for his part, holds that the two halachos can be measured by different yardsticks: an item that only enhances other foods is enough of a food to absorb maaser sheini money, and yet not enough of a food to enter the world of tumas ochlin.