Nazir having his hair removed through an indirect manner

Question

The Mishnah in Nazir 6:3 states:

סְתָם נְזִירוּת שְׁלשִׁים יוֹם. גִּלַּח אוֹ שֶׁגִּלְּחוּהוּ לִסְטִים, סוֹתֵר שְׁלשִׁים יוֹם. נָזִיר שֶׁגִּלַּח בֵּין בְּזוּג בֵּין בְּתַעַר אוֹ שֶׁסִּפְסֵף כָּל שֶׁהוּא, חַיָּב. נָזִיר חוֹפֵף וּמְפַסְפֵּס, אֲבָל לֹא סוֹרֵק. רַבִּי יִשְׁמָעֵאל אוֹמֵר, לֹא יָחוֹף בַּאֲדָמָה, מִפְּנֵי שֶׁמַּשֶּׁרֶת אֶת הַשֵּׂעָר:‏

A basic nazir [vow] is [for] thirty days. If he shaved or bandits shaved him it voids the thirty days. A nazir who shaved, whether with scissors, with a razor, or if he trimmed at all, is liable. A nazir can rub and trim but not comb. Rabbi Yishmael says: "He should not rub with earth, since it tears out the hair."

Suppose a Nazir does an action that indirectly causes his hair to be removed (for example, he undergoes chemotherapy and his hair falls out). Does doing that action void his Nezirus counting? Does the Issur of a Nazir shaving his head apply to indirect manners of hair removal?

On the one hand, the Mishnah seems to say that both Oneis (unavoidable action) and Psik Reisha (guaranteed outcome) are forbidden. That would seem to correlate accrately to this scenario.

On the other hand, perhaps other factors such as Davar She'eino Miskavein (unintentional result), not removing the hairs in a 'normal' manner, etc. would make this case not a violation of Nezirus.

Answer 1

The berayta and gemarot (Nazir 46b, Yuma 61b) regarding Nazir Memurat seem address a case in which hair loss is not a case of shaving, Gemara doesn't ask if the situation is induced. Similarly for a metsora without behonot, there is no distinction between accident and self mutilation.

All the cases of hairs cutting in gemara are active cutting, including Sach Nacha (Nazir 41a) are active cutting.

So for indirect way of hair loss there is no proof for stira. In every cases there is a lav with maasse, there is even a lav if someone else cut the hairs we have a lav lo yaavor ~ lo yaavir (עשה המגלח כמתגלח) (Nazir 44a). For lake of hairs. There are a couple of opinions in Gemara. Some tanaym think that he cannot finish the nezirut, Some else, and Rambam follows them, he can finish nezirut without hairs

Does the Issur of a Nazir shaving his head apply to indirect manners of hair removal?

The issur is found as directed manners only, there is a shita, Rabbi Yonatan's shita in berayta, that counts razor cutting only. The verse uses an active verb, "yaavor". But, issur or not, if the result is a loss of the majority of hairs, the nezirut's count is cancelled for 30 days. Rabbi Shimon Ben Yehouda un name of Rabbi Shimon is machmir for the loss of 2 hairs only.

the Mishnah seems to say that both Oneis (unavoidable action) and ...are forbidden.

Not forbidden for the mitgaleach, by oness he only needs to count again 30 days to reach a situation of "gadel pera".

Psik Reisha (guaranteed outcome) are forbidden.

Psik resha here is an active doing, with entire consciousness, but not entirely intentional.

davar sheeyno mitcaven

This is a range below psik resha but is also a full action.

would make this case not a violation of Nezirus?

I don't see any similar case in Gemara. Lo raiti is not a proof I know, but the verse points a mechanical action on the head.