*The question of shaving in general and using an electric shaver in particular is a problematic issue, both with respect to the underlying halakhic principles and with respect to the application of those principles to the technological reality of our day.
THE PARAMETERS OF THE PROHIBITION OF SHAVING
First of all, we must distinguish between the prohibition of "rounding the corners of the head" [hakafat ha-rosh], which we shall not discuss in this lecture, and the prohibition of "destroying the corners of the beard" [haschatat ha-zakan].
SHAVING WITH A RAZOR
The prohibition of shaving the corners of the beard appears in two places in the Torah: in Parashat Kedoshim directed to all of Israel and in Parashat Emor directed to the priests:
Neither shall you destroy the corners of your beard. (Vayikra 19:27)
Neither shall they shave off the corners of their beard. (Vayikra 21:5)
The commandments given to the priests and to all of Israel are assumed to be identical, and the Gemara applies what it learns from one to the other. Regarding all of Israel, the prohibition is formulated as one of "destroying," whereas regarding the priests, it is formulated in terms of "shaving." Therefore, the Mishna in Makkot 3:5 states:
One who makes a bald spot on his head, or rounds the corners of his head, or destroys the corners of his beard, or inflicts [upon himself] a single scratch over someone who died, is liable [to lashes]...
And he is not liable unless he removes [the beard] with a razor. Rabbi Eliezer says: Even if he removed it with a melaket or a rahitni [various types of tweezers], he is liable.
The reason that a person is only liable if he shaves with a razor is that the Torah only prohibited "shaving" that involves "destroying," as is stated in the prohibition directed to all of Israel in Parashat Kedoshim.
The prohibition of shaving applies to five parts of the face. It is difficult to identify the exact location of these five places. We are, therefore, stringent about the matter and relate to the entire beard as "corners of the beard" that may not be removed with a razor, with the exception of the mustache, which is definitely not a corner of the beard.
As we have seen in the Mishna, Rabbi Eliezer maintains that a person is liable even if he removes his facial hair with a melaket or a rahitni. These are instruments used to pluck the hair. The Gemara on this Mishna states (Makkot 21a):
Our Rabbis taught a Baraita: "[The priests] shall not shave the corners of their beard" (Vayikra 21:5). You might think that even if he shaves [his beard] with scissors, he would be liable. Therefore, the Torah teaches: "You shall not destroy [the corners of your beard]" (ibid. 19:27). And if [it said]: "You shall not destroy," you might think that even if he removed it with a melaket or a rehitni, he would be liable. Therefore, the Torah teaches: "They shall not shave." How so? Shaving that involves destruction. Say then that this means [shaving] with a razor.
The Gemara's basic definition of the biblically prohibited action is shaving that involves destruction.
SHAVING WITH A MELAKET OR A RAHITNI
The Gemara continues with a discussion of the position of Rabbi Eliezer:
Whatever you wish. If Rabbi Eliezer received the gezeira shava as a tradition, he should require a razor. If he did not receive that gezeira shava, scissors should also not be permitted.
In fact, he received the gezeira shava as a tradition, but he maintains that these too achieve shaving.
The Rishonim explain that according to Rabbi Eliezer the concept of shaving is not a technical characterization, but rather one is forbidden to shave with any instrument that is used for shaving. Since people do at times remove their facial hair with a melaket or a rahitni, shaving with such instruments is forbidden.
What is the difference between a razor and scissors? Why are scissors permissible even according to Rabbi Eliezer? The commentary to Makkot attributed to Rashi (s.v. talmud lomar gilu'ach) explains:
Scissors do not destroy, because they do not cut at the root like a razor.
Shaving that involves destruction - A razor is ordinarily used for shaving and [also] destroys. However, a rahitni destroys, but is not ordinarily used for shaving. And scissors are used for shaving, but do not destroy.
"Destroying" involves the removal of facial hair together with the roots, and scissors do not remove the roots.
To sum up, then, an instrument that removes facial hair including the roots and is ordinarily used for shaving (like a razor) is forbidden; an instrument that does not remove the roots (like scissors) is permissible; and an instrument that removes the roots, but is not the ordinary way of shaving (like a melaket or a rahitni) is the subject of a Tannaitic dispute.
SCISSORS SIMILAR TO A RAZOR
What length of hair is subject to the prohibition of shaving? As we shall see below, this is a key question regarding today's electric shavers.
A Nazirite is forbidden to shave throughout the period of his Naziriteship. At the end of his Naziriteship, however, he is obligated to shave his entire body. Thus the Mishna states in Nazir 39a:
A Naziriteship of unspecified duration lasts thirty days. Should [the Nazirite] shave himself or be shaved by bandits, thirty days are rendered void. A Nazirite who shaved, whether with scissors or with a razor, or who picked [his hair by hand], [even] a minute amount, is liable [to lashes].
A Nazirite is forbidden to shave, whether with a razor or with scissors. Even if he was shaved against his will, he forfeits his Nazariteship of up to thirty days and must start his count from the beginning.
Regarding this law, the Gemara (ibid. 39b) brings a Baraita that states:
A Nazirite whom bandits shaved, but left on him [hair long] enough to bend its tip to its root, does not forfeit [any days of his Naziriteship].
If a certain length of hair remains - "enough to bend [the hair's] tip to its root" - the shaving is not regarded as shaving, and the Nazirite does not forfeit his Naziriteship. The Gemara in the continuation writes that the Rabbis knew that this length represents seven days of growth. The Acharonim note that there is nothing "holy" about this length, for we see with our very own eyes that the rate of beard growth varies from one person to the next.
The Gemara in the continuation (40a) brings the following discussion:
Rav Chisda said: Regarding lashes, one hair; regarding impeding fulfillment [of the concluding head-shaving], two hairs; regarding forfeiting [his days of Naziriteship], he only forfeits [days] for most [of the hair on] his head. And [only] with a razor.
With a razor yes, but not with other things? But it was taught in a Baraita: From where do we know to include all things that remove [hair]? Say rather [anything] similar to a razor.
And the Tosafot (ibid. 40a, s.v. ubeta'ar) explain:
Which plucks the hair and destroys it at the root.
A razor, then, is characterized by plucking very close to the root of the hair. Therefore, if a Nazirite trims his beard, but leaves a certain minimum length of hair, he is not liable, nor does he not forfeit his Nazariteship.
Practically speaking, as we shall see below, the critical factor is "similar to a razor." The Shulchan Arukh rules:
A person is only liable for destroying the corners of his beard [if he shaves] with a razor. But scissors are permitted, even if they are similar to a razor.
The Rema appears not to disagree with the Shulchan Arukh's ruling:
Nevertheless, one must be careful, when shaving [with scissors] that it is the upper blade that moves, and not the lower one [= the blade that touches the skin], lest he cut only with the lower blade, it [effectively working] as a razor.
This law is not mentioned by the Rambam (Hilkhot Avoda Zara 12:7):
He is only liable if he shaves with a razor. As it is said: "You shall not destroy the corners of your beard" - shaving that involves destruction. Therefore, if he shaved his beard with scissors, he is not liable.
Commentators to the Rambam explain that when the Rambam says "he is exempt," he does not mean to imply that the practice is nevertheless forbidden, but rather he is exempt and the practice is permitted.
Another Mishna relating to the length of hair that is shaved is found in tractate Nida (52b):
The two hairs spoken of in regard to the red heifer and in regard to leprosy, as well as those spoken of anywhere else must be long enough for their tips to be bent to their roots; these are the words of Rabbi Yishmael. Rabbi Eliezer says: Long enough to be grasped by a fingernail. Rabbi Akiva says: Long enough to be taken off with scissors.
The Gemara on this Mishna states:
Rav Chisda said in the name of Mar Ukva: The law is in accordance with the views of all of them with respect to stringency.
It seems that the longest hair mentioned in the Mishna is that which is "long enough for their tips to be bent to their roots." As for the shortest hair, this is disputed by Rashi and the Rambam. According to the Rambam, the shortest hair is that which is "long enough to be taken off with scissors"; whereas Rashi understands that it is the hair which is "long enough to be grasped by a fingernail." In any event, the Gemara concludes that one must follow the stringency of all three opinions.
The main question arising from this passage is whether these lengths apply to other matters, in addition to the applications mentioned in the beginning of the Mishna. Does this Mishna have any ramifications regarding a Nazirite, or with respect to the prohibition of shaving, or the like? If we answer in the affirmative, we must practice stringency regarding the prohibition of shaving and a Nazirite. Due to the Mishna's heading, however, many commentators argue that the Mishna applies only to those realms mentioned in the heading, the common denominator being that they each require two hairs, which is not the case regarding a Nazirite or the prohibition of shaving.
THE DISCUSSION IN THE ACHARONIM
Thus far, we have dealt with the Mishnaic and Talmudic sources dealing with our issue. The main discussion found in the Acharonim revolves around a number of responsa relating to the topic. The primary discussion is between the Noda Biyehuda and the Chatam Sofer.
The Noda Biyehuda was asked (Yore De'a, mahadura tinyana, no. 80) whether it is permissible to shave in two stages: first, to remove the bulk of one's beard with scissors so that the remaining stubble is too short to be classified as hair, and then afterwards remove that stubble with a razor, for the stubble that remains is not called hair. The Noda Biyehuda writes that this question was already raised in Responsa Besamim Rosh, and the conclusion there is that the practice is allowed: The first stage was performed with scissors, and the second stage is not considered shaving (because the hair is not long enough to be considered hair). The Noda Biyehuda himself disagrees with the Besamim Rosh, but for a side reason. According to him, there is no minimum length for hair with respect to the prohibition of shaving, so that there is no such thing as hair "that is not called hair" with regard to shaving. The Noda Biyehuda has his doubts about this assertion. He writes that he does not wish to treat the matter at great length, for the allowance is liable to lead to all kinds of violations.
Over and beyond what the Noda Biyehuda says, there seems to be a practical difficulty with what the questioner had proposed, for it is exceedingly difficult for a person to remove all his facial hair with scissors, in such a way that there remains not a single hair long enough to be classified as hair.
The Chatam Sofer vigorously attacked the Noda Biyehuda. It was clear to him that the proposed practice was absolutely forbidden, and not merely for side reasons. In effect, the Chatam Sofer disagrees with the Shulchan Arukh, and says that the scissors similar to a razor are forbidden. When the Gemara says that scissors are permitted, it is referring to scissors that do not "destroy" the hair at all. According to him, therefore, already at the first stage of the proposed practice, when the person trims his beard with scissors leaving hair of extremely short length, he violates the prohibition. The Tzemach Tzedek also discusses the issue at length, saying that the Shulchan Arukh's ruling is subject to disagreement.
SHAVING ON CHOL HA-MO'ED
What drove the Chatam Sofer to deal with this question was the issue of shaving on Chol ha-Mo'ed. In another responsum, the Noda Biyehuda permitted shaving on Chol ha-Mo'ed for those who have a great need to shave, for example, a person who must appear before non-Jewish officials, or the like. He permitted shaving on Chol ha-Mo'ed by way of a poor person who has nothing to eat, provided that the person receiving the shave did not enter the holiday unshaven. Some have explained the Noda Biyehuda's allowance with the fact that the people who had dealings with the non-Jewish officials were accustomed to shave with a razor. The Noda Biyehuda, therefore, permitted them to shave every day - even on Chol ha-Mo'ed - in order to prevent them from violating a Torah prohibition: If they shave every day, they never violate a Torah prohibition, because the hair never grows long enough to be subject to the prohibition of shaving with a razor. The Chatam Sofer absolutely disagrees, arguing that even in such a case they violate a Torah prohibition.
Rabbi Tzvi David Hoffman, author of Responsa Melamed Leho'il, was asked about a sick person who was told by his doctors that he must shave every day with a razor. Is he permitted to use the allowance found in Responsa Besamim Rosh? Rejecting what the Chatam Sofer had said about the Besamim Rosh, Rabbi Hoffman inclined to allow the ailing patient to rely on the latter's position.
Let us summarize by saying that according to the Chatam Sofer and his camp, shaving one's beard is forbidden, even with scissors. Obviously, then, any type of electric shaver is forbidden, and the use of such a machine may well involve the violation of a Torah prohibition.
The Jewish community at large has not accepted this ruling. Hungarian Jews who accepted the rulings of the Chatam Sofer were accustomed to leave a short, bristly growth of beard on their faces and not to give themselves a clean shave. Most people, however, follow the Shulchan Arukh, with whom the Chatam Sofer disagrees, and allow shaving with scissors that are similar to a razor. Therefore, the main question that we must deal with concerns the definition of "scissors similar to a razor" that are permitted. How are such scissors different from a razor that is forbidden?
It may be argued that practically speaking all electric shavers are permitted, because there is something that intervenes between the blade and the skin. Rabbi Tzvi Pessach Frank, in his Responsa Har Tzvi, put forward such an argument in passing. He was asked whether using an electric shaver is regarded like cutting with one's hands. He answered in the affirmative, despite the fact that it is the electric motor that performs the action. In the course of his discussion, he mentions the principle mentioned above. This, however, cannot be considered a clear halakhic statement on the part of Rabbi Frank; the responsum does not deal directly with the permissibility of shaving with an electric razor.
Rabbi Nachum Rabinowitz, Rosh Yeshiva of Yeshivat Ma'ale Adumim, in his book, Melumadei Milchama, deals with this issue. He allows all electric shavers, arguing that they should be treated like a melaket and a rahitni. According to him, these instruments are characterized by the fact that that they cut each hair separately, as does an electric shaver. This stands in contrast to a razor that cuts off many hairs at the same time.
It is difficult, however, to rely on this argument with respect to biblical prohibitions, for the Rishonim understood that a melaket and a rahitni are permitted because they are not designed for shaving, and not because they cut each hair separately. It goes without saying that it is difficult to argue that an electric shaver should not be regarded as an instrument designed and intended for shaving.
Another possible distinction between a razor and scissors is based on the fact that scissors cut the hair using two blades, whereas a razor cuts it with a single blade. If this is the distinction between scissors and a razor, we must then deal with a practical issue: Does an electric shaver cut with a single blade or with two blades (i.e., the blade and the protective metal screen).
One might have expected that since an electric shaver cuts the hair through the protective screen, it should leave stubble in the length of the screen's thickness. The fact, however, is that no hair remains. The biological explanation is that hair is flexible, and that in the course of shaving, it is pulled into the machine and then afterwards the remaining hair sinks back into the skin. This phenomenon raises a question: Do we follow the physical results that a small length of hair is left uncut, or do we follow the visible results that no unshaven hair remains?
Furthermore, we must consider two additional factors which may be relevant to the decision-making process:
1) Does the blade touch the skin? If the machine pulls in the hair, perhaps the skin is also pulled through the openings in the screen.
2) Does the machine cut the hair solely with the blade like a lawn mower, or with a scissors-like action, the protective screen functioning as a second blade?
These technical issues must be clarified, and only then can the Halakha be decided.
Rabbi Shabtai Rappaport, in Techumin 13, maintains that the main issue is the second question: Does an electric shaver remove the hair solely with the cutting action of the blade, or with the combined scissors-like action of the blade and the screen. He argues that a simple test may be performed to determine whether a shaver is "kosher" or not: does the shaver work without the screen? If the blade cannot cut the hair without the screen, then the shaver is permitted. Even if the blade can cut without the screen, the shaver may still be "kosher," for it is possible that when the screen is in place, the blade cuts together with the screen. It is also necessary to discuss the first question raised above.
Another question must also be addressed: What is the law if most of the hairs are cut through the combined action of the blade and the screen, but some of the hairs are cut by the blade alone?
In the past, Machon Tzomet would test different types and brands of shavers, and publish its conclusions regarding which of them were permitted for use, following the criteria proposed by Rabbi Rappaport. If the shaver was unable to cut the hair without the screen in place, it was permitted. In recent years, Machon Tzomet has ceased dealing with this issue, because close-up photographs taken by the Phillips Company have revealed that even with respect to shavers that had been declared "kosher," the blade usually cuts the hair even before it touches the screen. Thus, we are once again faced with the basic question: Either all shavers are kosher or they are all forbidden. Rabbi Rappaport, however, remains firm in his position, and continues to test shavers, just as he had done prior to the publication of the photographs.
Let us conclude by saying that the posekim of our generation accept the fact that the community at large is inclined to be lenient on the issue, but they have difficulty finding clear justification for such leniency.
(Translated by David Strauss)
*This lecture was delivered in the Yeshiva in Shevat 2002
 Responsa Besamim Rosh is attributed to the Rosh (Rabbenu Asher ben Yechiel), but there is widespread disagreement whether the work is authentic or a forgery. The Chatam Sofer (cited below), who disagrees with the Noda Biyehuda, referred to it as Kizvei ha-Rosh (Lies of the Rosh). Indeed, it is very strange that the Rosh should permit a circumvention of the law that is liable to lead to forbidden shaving.