Towards the end of Parashat Shoftim, the Torah presents the prohibition known as bal tashchit, which forbids destroying edible food. This prohibition is introduced in the context of the Torah’s discussion of warfare, where it addresses the case of a siege against an enemy city. The Torah forbids cutting down fruit trees during the siege to obtain wood, and allows cutting down only “a tree that you know not to be a tree of food” (20:20).
A number of Acharonim noted that this verse appears, at first glance, to call into question the position famously taken by the Rambam concerning the status of sefeikot – halakhic uncertainties. The well-established halakhic principle of “safeik de-Orayta le-chumra” requires assuming the stringent possibility when an uncertainty arises regarding a Torah law (as opposed to a law enacted by the Sages). For example, if there is a question as to the status of a morsel of food, and a potential Torah violation is at stake, one must refrain from the food to avoid the risk of a Biblical transgression. However, the Rambam, in Hilkhot Tum’at Meit (15:12), writes that this principle was itself enacted by the Sages. As far as Torah law is concerned, according to the Rambam, one may act leniently in a situation of halakhic doubt, as it was Chazal who instituted that one must act stringently. The Rashba, both in a published responsum (401) and in his Torat Ha-bayit (4:1), famously disputed the Rambam’s position, and maintained that Torah law itself demands assuming the stringent possibility in situations of doubt. Some questioned the Rambam’s view in light of the Torah’s allowing cutting down only trees “which you know not to be a fruit of food” – indicating that a tree whose status is in doubt may not be cut. The fact that the Torah permits cutting only trees which are definitively known not to bear fruit seems to suggest that Torah law forbids following the lenient possibility in situations of doubt – in direct contradistinction to the Rambam’s position.
Various answers have been proposed in defense of the Rambam’s view. The simplest answer, perhaps, is that the context of bal tashchit marks an exception to the rule. The Yad David commentary (by Rav Yosef David Sinzheim of Strasbourg) to Masekhet Bava Kama (91b) writes that to the contrary, the fact that the Torah specified the need for definitive knowledge of the tree’s status in this context actually proves the Rambam’s view, that generally, we may be lenient in situations of doubt. The Torah had to specifically forbid cutting trees until they are definitively determined not to bear fruit because in other contexts, Torah prohibitions do not apply when there is uncertainty. This context marks an exceptional instance where the Torah does not allow relying on the lenient possibility, and instead applies a prohibition even when the status of the item in question is uncertain.
Rav Chaim Kanievsky, in his Ta’ama Di-kra, suggests a different answer, explaining that the verse’s intent is to emphasize that even fruit trees that do not currently bear fruit may not be cut. The phrase “which you know not to be a tree of food” should be understood as excluding not trees whose status is uncertain, but rather trees which at the present have no fruit but are capable of producing fruit. A tree may be cut only if it is a type that does not produce fruit; if it can produce fruit, then it may not be cut even if it currently has no fruit. According to this reading of this verse, it has nothing at all to do with the topic of sefeikot, and thus poses no difficulty with regard to the Rambam’s controversial position.
Others suggest that the Torah refers here to a tree which at one point bore fruit, but is no longer capable of producing fruit (as Seforno explains), such that even the Rambam would concede that definitive knowledge of its incapacity is necessary to permit cutting it down. The background to this answer is the theory advanced by several Acharonim that in a case of “ikba issura” – where it is known that a forbidden substance was at one time present – the Rambam agrees that Torah law forbids relying on the lenient possibility. After all, the Torah requires offering a special sacrifice (“asham talui”) in the case of an uncertain violation (if the prohibition carries the punishment of kareit), which should, at first glance, prove that Torah law requires acting stringently in situations of uncertainty. The common answer given to defend the Rambam’s view is that this sacrifice is required only if the forbidden item was definitely involved – such as in the case where one had forbidden food and permissible food, but he does not know which food he ate (see Rambam, Hilkhot Shegagot 8:3). In such a case, where forbidden food was definitely present, and it is uncertain which portion of food is the forbidden piece, the Rambam agrees that one must abstain from both pieces on the level of Torah law – as evidenced by the obligation to bring an atonement sacrifice if a person ate one of the pieces. Accordingly, some have suggested that when the Torah permits eating only “a tree which you know not to be a tree of food,” it refers to a fruit tree which has been determined to be no longer capable of producing fruit. Such a tree may be cut only if it is certain that it cannot produce more fruit, since this is a case of “ikba issura,” where the prohibition was definitely applicable at one point. In such situations, even the Rambam agrees that one must assume the prohibition is applicable until he can be certain that it isn’t. (This answer was suggested by the Ma’ayan Ha-chokhma, cited by Chatam Sofer, Y.D. 102 and Bava Batra 26; and by Rav Yosef Shaul Nathanson, Shoel U-meishiv – Mahadura Kama 2:146.)