4/28/202320 min read

Philosophic Differences between Rambam & Ramban


Rabbi David Bassous

Congregation Etz Ahaim

Highland Park NJ

1. ‘Korbanot’, Sacrifices.

2. The Holiness of Hebrew, Lashon Hakodesh.

3. Astrology and Black Magic.

4. Lessons from a nazir.

5. Going to a doctor.

6. Use of ‘occult’ medicine.

7. ‘Sefeika de-oraitta le-humra’.

1. ‘Korbanot’, Sacrifices

Rambam in his ‘Moreh Nevukhim,’1 The Guide for the Perplexed, discusses the philosophy of the korbanot (temple sacrifices) and the choice of the different species of animals. He states that the types of sacrificial animals to be used in the holy temple (Bet Hamikdash) were chosen specifically because they were considered to be gods by the pagan religions that abounded at that time and some that are still existent. We were told to sacrifice these ‘gods’ to the One and only true G-d to inculcate within us a firm belief in their impotence.

This is the reason why we were commanded to kill a lamb on Passover, and to sprinkle its blood on the doorposts. We had to free ourselves of evil doctrines and to proclaim the opposite, then the very act which was then considered the cause of death would be the cause of deliverance from death. “And the L-rd will pass over your door, and will not allow the destroyer to come into your houses to smite you.”2 They were rewarded for performing openly a service that was objected to by the idolaters.

According to Rambam one of the objectives of G-d through the Torah is to wean the Jewish people away from idolatrous practices. One of the missions of the Torah is to destroy the idolatrous taboos and superstitions that are rooted in idolatry. This goal is to be achieved by advocating the very opposite of that demanded by the surrounding idolatrous cults.3

Ramban in his commentary on the Torah4 disagrees and states that if the whole purpose of the sacrifices was to inculcate within us a revulsion of these ‘gods’ it would have been better if we were to eat [these animal-deities] to our full, which would be considered by idolaters forbidden and repugnant, and something they would never do. He brings proofs from the Torah that G-d desires korbanot, the most explicit in the cases of Abel and Noah.

He advances two reasons why korbanot are required and even desirable:

The sacrifices are basically atonement for our sins All these acts are performed in order that when they are done, a person should realize that he has sinned against G-d with his body and soul, and that ‘his’ blood should really be spilled and ‘his’ body burned, were it not for the loving-kindness of the Creator, Who took from him a substitute and a ransom, namely this offering, so that its blood should be in place of his blood, its life in place of his life, and that the chief limbs of the offering should be in place of the chief parts of his body. The portions [given from the sin-offering to the priests] are in order to support the teachers of the Torah, so that they pray on his behalf. The reason for the daily public offerings (Temidim) is that it is impossible for the public [as a whole] to continually avoid sin.

The second reason he advances is kabbalistic in nature and unexplained.

2. The Holiness of Hebrew, Lashon Hakodesh

Rambam is of the opinion that there is no intrinsic sanctity in ‘Lashon Hakodesh’ but rather its sanctity is derived from its lack of vulgar and coarse language. Though he speaks of the “kedushah” of Hebrew (Kedushat Halashon),5 Rambam does not mean that there is a sacred quality in the language. He uses “kedushah” in the sense of moral restraint, pointing out that Hebrew has avoided coining words for the reproductive organs nor for semen, nor for urination or excretion, excepting in indirect language or for the act of intercourse.6

Ramban however states that Hebrew is a holy language because it was the vehicle used by G-d to create the world and communicate with man, through the Torah. He states that according to Rambam Hebrew should have been only been called the ‘modest language’ not a Holy Language.7 Ramban discusses the idea of the holiness of the Hebrew language in his commentary on the Torah8 while explaining the phrase “half a shekel ‘beshekel hakodesh’ - of the shekel of holiness.”

“Since the standard shekel of valuation and the redemption of the firstborn,9 which are holy matters, were given in that coin, as also all shekels mentioned in connection with the tabernacle, and all moneys the amount of which is specified in the Torah,10 therefore the Torah calls it the ‘shekel of holiness’.

I am of the opinion that this is the same reason why our Rabbis call the language of the Torah “The Sacred Language,” because the words of the Torah, and the prophecies, and all words of holiness were all expressed in that language. It is thus the language in which the Holy One, blessed be He, spoke with His prophets, and with His people.11 In this tongue He is called by His sacred names. In that tongue He created His world, and called the names shamayim (heavens), eretz (earth) and all that is in them, His angels and all His hosts - he called them all by name.12 In that language He called the names of the holy ones that are in the earth: Abraham, Isaac, Jacob, Solomon, and others.

3. Astrology and Black Magic

In his famous Letter on Astrology,13 Rambam vigorously denounced belief in any astrological influence over human life. He described the philosophical opposition to astrology as a thoroughly naturalistic one, which did not allow for the influence of the stars. The correct Jewish belief, in his view, agreed with this and also accepted the notion of G-d’s Providence, thereby utterly rejecting any astrological influences. Rambam declared that he had read all the extant astrological books, and decried the fact that people naturally give credence to any doctrine that is recorded in a text, even if it is nonsense. Yet most medieval philosophers, including Rabbi Abraham Ibn Ezra,14 believed in astrological influences and even went so far as to claim that empirical evidence supported this belief. No less a radical thinker than Rabbi Levi ben Gershon (Ralbag), was a firm believer in the effects of the stars upon human life, and based his position on empirical evidence.15

Rambam’s view on astrology is diametrically opposed to Ramban’s view that part of G-d’s plan was that higher celestial objects do have some control over human affairs. While Rambam superimposed his view of Divine Providence upon a naturalistic order that excluded any possibility of astrological influences, Ramban built his doctrine of “hidden miracles” upon an infrastructure of a world governed by the stars. “Nature,” according to this view, included astrological influences.

Ramban’s View

A far cry from the rational view espoused by the Rambam16 that astrology, sorcery and witchcraft: “are all imaginary and foolishness which attract only those that are deficient in knowledge” is the view of Ramban.

In his commentary on the Torah17 he discusses the prohibitions of sorcery and divination and concludes that there is some truth to them, they have a basis in nature and are part of G-d’s design of the universe.

Know and understand concerning the subject of sorcery, that when the Creator, blessed be He, created everything from nothing; He made the higher powers guides for those below them. Thus He placed the earth and all things that are thereon in the power of the stars and constellations, depending on their rotation and position as proven by the study of astrology. Over the stars and constellations He further appointed guides, angels, and “lords” which are the souls [of the stars and constellations]. Their behavior from the time they come into existence for eternal duration, is according to the pattern the Most High decreed for them. However, it was one of His mighty wonders that within the power of these higher forces, he put configurations and capacities to alter the behavior of those under them. Thus if the direction of the stars towards the earth be good or bad to a certain country, people, or individual, the higher dominions can reverse it of their own volition, as they have said, “The opposite of the word oneg (pleasure) is nega (plague).” G-d ordained it because He, blessed be His Name, changes the times and the seasons;18 He calls for the waters of the sea to do with them at His Will, and brings on the shadow of death in the morning without changing the natural order of the world, and it is He Who made the stars and constellations move about in their order. Therefore, the author of the Book of the Moon, the expert in [the field of] necromancy, said, “when the moon, termed ‘the sphere of the world’ is, for example, at the head of Aries (the Ram) and the constellation thus appears in a certain form, you should make a drawing of that grouping, engraving on it the particular time [when this relative position appears] and the name of the angel - one of the names mentioned in that book - appointed over it. Then perform a certain burning [of incense] in a certain specified manner, and the result of the influence [of the relative position of the stars] will be for evil, to root out and to pull down, and to destroy and to overthrow. And when the moon will be in a position relative to some other constellation you should make the drawing and the burning in a certain other manner and the result will be for good, to bud and to plant.” Now this, too, is the influence of the moon as determined by the power of its [heavenly] guide. But the basic manner of its movement is by the wish of the Creator, blessed be He, Who endowed it so in time past, while this particular action is contrary thereto.

This then is the secret of [all forms of] sorcery and their power concerning which the rabbis have said19 that “they contradict the power of the Divine agency,” meaning that they are contrary to the simple powers [with which the agencies have been endowed] and thus diminish a certain aspect of them. Therefore, it is proper that the Torah prohibit these activities in order to let the world rest in its customary way, which is the desire of its Creator. This is also one of the reasons for the prohibition of kilayim (mixing seeds), for the plants resulting from such grafting are strange, giving rise to changes in the ordered course of the world for bad or good, aside from the fact that they themselves constitute a change in Creation, as I have already explained.20

According to Ramban the Torah does not consider all the practices mentioned in these verses to be abominations. He singles out ‘meonein’ and ‘menahesh’ as not included among the abominations and although the Torah restricts their practice by Jews it would seem according to his view that there is no prohibition for gentiles to engage in these practices:

The Torah states, For ‘all’ that do these things are an abomination unto the Eternal, but it does not say “for those that do ‘all’ these things…” because the Torah [in calling the practitioner an abomination] refers to most [but not all] of these practices. For the ‘meonein’ who divines by observing the clouds and the ‘menahesh’ who divines by means of the wings or chirping of birds are not abominable, and G-d did not dispossess the Canaanites on their account, because all human beings desire to know things that are not come upon them, and engage in what they consider to be pursuits of wisdom.

In fact ‘meonein’ and ‘menahesh’ were considered by Ramban to be praiseworthy sciences for the pagans to delve into, and even a wisdom.

Now all this is not considered abominable for the nations, instead it is considered wisdom for them. Thus the Rabbis said:21 “And Solomon’s wisdom excelled the wisdom of all the children of the east. What was the wisdom of the children of the east? They were wise and astute in divination of birds.”... And Solomon learned all this as part of his wisdom. Now, the knowledge [referred to by the Midrash] is the understanding of the chirping of birds, and the ingenuity to explain a matter through spreading wings.

However, these activities, though allowed to be studied by Jews are prohibited to be acted on only because we are to have more direct access, through prophecy and the Urim Ve Tumim, to the Creator Himself.

Now, when the Torah included the diviner by clouds and the [other] diviners with the abominations mentioned, it explained that, these nations, that you are to dispossess, hearken to diviners [by clouds], and unto [other] diviners for their wisdom is to know future events, but as for you, the Eternal your G-d has not suffered you to do so. The Torah is thus stating, “G-d has prohibited you these specified practices [such as passing a child through the fire] because they are abominations before Him and because of them He drove these nations out from before you. He further forbade the enchanters and the diviners to you, because He gave you great eminence in setting you on high above all the nations of the earth, in that He will raise up a prophet in the midst of you and place His words in his mouth and you will hear from him what G-d will do. To know the future it will be unnecessary for you to resort to a diviner or soothsayer who receives [the knowledge] from the stars or from the lower powers among the lords of above, whose words are not all true and who do not provide all necessary information. But prophecy informs us of G-d’s desire and not one of its words will fall to the earth.” It is this, that the Torah explains [that if ever an ostensible prophecy does not come to pass], the Eternal has not spoken. Thus you are His portion and His treasure, hearing His counsel form His mouth, while theirs is the portion of the constellations which they follow, this being the sense of the verse, but as for you, the Eternal your G-d has not suffered you so to do. This is the meaning of, which the Eternal your G-d has allotted unto all the people, as I have explained. And in the Sifre the Rabbis have said: They listen to diviners [by the clouds] and [other] diviners. Perhaps you will say, “They have a source from which to inquire.” The Torah therefore states, but as for you, the Eternal your G-d has not suffered you to do so. This is proof to all what we have explained that with respect to the diviners some root of the matter is found in them, and therefore Israel had a [legitimate] complaint in being enjoined from making use of them [i.e. the diviners].

And on the next verse22 Ramban continues this theme:

‘You shall be whole-hearted with the eternal your G-d.’ The meaning of this is that we are to direct our hearts to Him only, and believe that He alone does everything. It is He Who knows the truth about all future events, and from His prophets, or from His pious ones, in other words the Urim and Tumim we are to inquire about future events. We are not to inquire of the astrologers or from anyone else, or by any means to trust that their words will be fulfilled. Instead, if we hear any prediction [of the diviners] we should say, “Everything is in the hands of Heaven, for He is the G-d of gods Who is supreme above all, the Omnipotent One over everything, Who changes the set order of the stars and constellations at His Will, Who frustrates the tokens of the impostors, and makes diviners mad” and we are to believe that future events will occur according to man’s drawing closer to His service. Therefore after the warning against inquiring about future events from diviners, and of seeking on behalf of the living from the dead, he stated that you are to be whole-hearted with G-d in all these matters and not be afraid of those who tell of things to come. Rather, you should inquire of His prophet and to him shall you hearken. And this is the opinion of Onkelos who translated, “You shall be whole-hearted in the fear of the Eternal your G-d,” meaning that you should not be deficient in the fear of Him, for tamim (whole) indicates perfection in a thing, just as “seh tamim” (a lamb that is perfect) means one that is without blemish and any deficiency. This verse [before us] constitutes a positive commandment. I have already mentioned this in connection with the verse, and be you whole-hearted.

Ramban himself in his commentary quotes the contrary opinion of the Rambam and dismisses it, basing himself on what appears to be firsthand witness accounts of bird divination that were successful and on various Talmudic and other rabbinic statements:

Now many scholars dispose themselves to be liberal with regard to these enchantments by saying that there is no truth in them whatsoever,23 for who tells the raven or the crane what will happen? But we cannot deny matters publicly demonstrated before the eyes of witnesses. Our Rabbis also, acknowledged their existence, as they have said in Midrash Rabbah: “For a bird of the air shall carry the voice”24 - this refers to the raven and the craft of tiarin. Birds in Arabic are called tiar and those versed in the divination of birds are called tiarin. This subject is also mentioned in the Talmud.25

But there is a secret to this matter. We have already made known26 that the constellations have lords that lead them, these being “the souls” of the circuits of the spheres, and the lords of the tail and [head of] Aries (the Ram) are near the earth, these being termed “the princes of the quiver,” that make the future known. It is through them that the signs in the birds indicate things to come, not for long duration or distant future do they tell, but only of events that are about to happen. Some make them known by utterance of bitter sounds [resembling wailing] over the dead, and some by spreading their wings. This is what has been said, for a bird of the air shall carry the voice - a reference to those who suggest by their wings.

According to Ramban there is some truth in Divination, sooth-saying and astrology but we Jews are only to believe in G-d alone and inquire through prophecy and the Urim VeTummim of the Supreme being who is in control over the whole system and not through His celestial deputies who he appointed under Him. Ramban utilized the idea that the Jews are directly under G-d’s Providence and are therefore not subject to the celestial constellations as are other nations to explain a large variety of biblical verses and laws. Yet, he maintained that this idea also assumed a universe determined by the stars.

4. Nazir

Generally a sin offering is brought for atonement of a sin committed in error. But the Nazirite has fulfilled his vow so why did the Torah obligate him to bring a sin offering. Ramban27 states that the reason why a Nazirite must bring a sin offering has not been explained and he offers the following explanation:

This man sins on completing his vow, for until now he was separated in sanctity and the service of G-d, and he should therefore have remained separated forever, continuing all his life consecrated and sanctified to G-d...instead of going back to be defiled by desires of this world.

According to Ramban’s philosophical perspective being a Nazir is an ideal and spiritually elevated situation. A person should aspire to be one and at least after having tasted the holy lifestyle should desire for it to continue instead of lowering him or herself to the ‘normal’ more mundane and material lifestyle of ‘common man’.

Rambam addresses this issue in two places. In ‘Shemonah Perakim’ his introduction to Pirke Avot Chapter 4 he discusses the virtue of charting a medium course in life and the danger involved in asceticism. Rambam explains that, at certain times, many of the pious adopted ascetic practices as a safeguard against excessive involvement in materialism. However, they never regarded such practices as a goal in their own right. Others observed their behavior and mistook asceticism for an end rather than a means to achieve the middle path.

From his statements, it would appear that there are two drawbacks to asceticism:

a) It might lead a person to poor health, illness, and a lack of strength, which would prevent him from serving God as the Rambam states in Halachah 3.

b) A person might err and feel that he has fulfilled his obligation to serve God through these ascetic practices. As a result, he may never feel the need to dedicate himself to the service of God as He prescribed in the Torah.

There is a third disadvantage hinted at by Rambam’s statements in Hilkhot Deot that it defeats G-d’s purpose in Creation.

He states:

A person engaged in asceticism will surely become ill. Similarly, such people will become spiritually ill from using remedies while they are healthy. Our perfect Torah leads to our fulfillment, as one who knew it states,28 G-d’s Torah is perfect, granting wisdom to the foolish, restoring the soul. [It] does not command us to follow any of these paths. Rather it desires that man should live naturally, following the middle path, eating a moderate portion of food that he is permitted to eat, drinking a moderate portion of what he is permitted to drink, engaging in permitted sexual relations in a moderate way, and creating a society [based on] righteousness and justice.

He need not live in caves or on mountains, nor wear sackcloth and (coarse] wool. There is no need to weary the body, or to drain it or oppress it. Our oral tradition29 has warned us against [such an approach in its interpretation of the Torah’s indictment of] a Nazirite as one who “sinned against [his] soul.”30 Our Sages ask: ‘How did the person “sin against his soul?” They explain: “He held himself back from [drinking) wine.” Can we not extrapolate from this? If a person who refrains from drinking wine needs atonement, surely this would apply to one who holds himself back from involvement in other worldly things.

Similarly in Hilkhot Deot Chapter 3 Rambam elucidates this point as follows:

A person might say, “Since[the pursuit] of envy, desire, and the like, are a wrong path and drive a person from the world I shall separate from them to a very great degree and move away from them to the opposite extreme.” For example, he will not eat meat, nor drink wine, nor live in a pleasant home, nor wear fine clothing, but, rather, [wear] sackcloth and coarse wool and the like - just as the pagan priests do.

This, too, is a bad path and it is forbidden to walk upon it. Whoever follows this path is called a sinner [as implied by Numbers 6:11] concerning a nazarite: “and he [the priest] shall make an atonement for him, for his having sinned because of the dead.”31 Our sages declared: “If the nazarite who abstained only from wine requires atonement, how much more so does one who abstains from everything.”32

Therefore, our Sages directed man to abstain only from those things that the Torah denies him and not to forbid unto himself permitted things by vows and oaths [of abstention]. Thus, our sages stated:33 “Are not those things that the Torah has prohibited sufficient for you must you forbid additional things to yourself?”

This general statement also refers to those who fast constantly are not following a good path, [for] our sages have forbidden one to mortify himself by fasting. Of all the above, and their like, they directed and said: “Do not be overly righteous and clever; why make yourself desolate?” (Ecclesiastes 7:16).

5. Going to a doctor

Ramban in his commentary to the Torah in Parashat Behukotai offers his view on a person turning to doctors for healing.

Ramban discussed the halakhic imperative for a physician to heal. He understood the Talmudic statement ‘she’ain darchai benai adam berephuot’ - it is not in the manner of people to use medicines (Berakhot 60a) to mean that the pursuit of medicinal aids was once a deviation from the norm. The ideal procedure that was followed in Israel during prophetic times was for a sick man to realize that his illness was a punishment from G-d (one of his manifold “hidden miracles”) and to respond by consulting a prophet. Eventually, however, the deviation became the norm, and the populace in general began to consult doctors. Responding in kind, G-d left the Jewish people to the vicissitudes of the elements. The responsibility of a doctor to heal came, therefore, only as a result of lack of faith to seek prophets.

6. Use of ‘occult’ medicine

While Rambam is unconditionally negative to assorted magical practices he is positive in certain of their application toward medical practice. For example, the Mishnah in Pesahim mentions a “book of cures” that was hidden by King Hezekiah.34 Rambam argued strongly against the view that Hezekiah hid the book because people were putting their faith in medical books and not in G-d as the ultimate Healer. He maintained that the book that Hezekiah hid contained magical cures based upon the use of amulets. The author of the book had intended only that readers of his work study the phenomena described in it and not apply the procedures suggested therein to real situations. However, when people began to make practical use of the text, Hezekiah decided to hide it. Rambam’s refusal to countenance, the thought that the Rabbis would ever restrict the scope of beneficial remedies, and his declaration that the Torah is interested in the well being of the human body supplement his disavowal of sham magical cures.

Rambam did concede the validity of empirical medicine, i.e., cures that “worked” even though their causes remained unknown, and did not advocate the position of the Dogmatic physicians of antiquity who exclusively based their cures upon “principles” (i.e., treatments whose causes were fully understood in light of contemporary science) alone. In Moreh Nevukhim (3:37) he stated:

You must not consider as a difficulty certain things that they [the Rabbis] have permitted, as for instance the nail of one who is crucified and a fox’s tooth.35 For in those times these things were considered to derive from experience and accordingly pertained to medicine and entered into the same class as the hanging of a peony upon an epileptic and the giving of a dog’s excrement in cases of the swelling of the throat and fumigation with vinegar in cases of hard swelling of the tendons. For it is allowed to use all remedies similar to those that experience has shown to be valid even if reasoning does not require them. For they pertain to medicine and their efficacy may be ranged together with the purgative action of medicines.

Three categories of cures exist according to Rambam:

1. Effective ones based upon the laws of natural science.

2. Sham cures of occult virtue.

3. Cures of “empirical medicine,” a category which itself exists only due to our current imperfect knowledge concerning the science of medicine.

Any cure that is part of the third category which truly “works” would be permitted, and ultimately, with advancement of scientific thought, will also be classified with cures of natural science. If a supposed cure would be shown in reality not to work, it would immediately fall into the second category above and, from a halakhic perspective, would be subsumed under the prohibited rubric of darkhei Emori (Emorite usage). Thus, the general rule that “anything which pertains to medicine does not pertain to Emorite usage” remains constant, even as the class of specific cures may not. Hence, Rambam could state that the fox’s tooth, which the talmudic Rabbis assumed “worked”, in fact did not.36

In light of Rambam’s categories of cures and in view of his attack in Moreh Nevukhim against the use of amulets his codification in Mishneh Torah37 of the law that permits one to wear an amulet on Shabbat poses a difficult problem. One may only wear an amulet, according to the Mishnah, which has been proven effective; since it has a legitimate purpose, the wearer would not violate the prohibition of carrying on Shabbat. In this sense, an amulet may be compared to apparel. Yet Rambam himself forcefully de-legitimized all use of amulets, as he claimed that they did not cause any effect. How, then, could he allow one to be worn on Shabbat?

Writing in Provence in the beginning of the fourteenth century, Rabbi Menahem ha-Meiri states that amulets “work,” not because of any intrinsic property they possess, but because people believe that they can cure. In his view, amulets are, in effect, placebos effecting psychosomatic cures. Although the amulets are not intrinsically effective, and only objectively work because one subjectively thinks that they do, this is irrelevant with regard to the law of carrying on Shabbat. If one’s subjective point of view is that he is wearing a “tried and true” amulet, this fact, which itself generates the objective efficacy of the charm, suffices to place the amulet into the category of apparel and other objects that may be worn on Shabbat. If one assumes that Meiri’s view was Rambam’s unarticulated assumption as well, the problem in Hilkhot Shabbat is solved. In any event, this issue does not alter Rambam’s general perspective upon the matter.

Ramban on Healing

Ramban discussed the halakhic imperative for a physician to heal in his commentary on Parashat Behukotai. He understood the Talmudic statement ‘she’ain darchai benai adam be rephuot’ (it is not in the manner of people to use medicines (Berakhot 60a) to mean that the pursuit of medicinal aids was once a deviation from the norm. The ideal procedure that was followed in Israel during prophetic times was for a sick man to realize that his illness was a punishment from G-d (one of his manifold “hidden miracles”) and to respond by consulting a prophet. Eventually, however, the deviation became the norm, and the populace in general began to consult doctors. Responding in kind, G-d left the Jewish people to the vicissitudes of the elements. The responsibility of a doctor to heal came, therefore, only as a result of lack of faith to seek prophets.

Hence, when Ramban discussed whether or not one could receive medical assistance from demons, he operated with assumptions that were vastly different from those held by Rambam. Can a potent supernatural agent with whom the Torah has forbidden consultation be used in the context of medicine, a pursuit itself advocated only as a concession to human nature? In Torat ha-Adam he permitted such activity, as long as the sorcerer did not invoke the names of other gods.

Rashba recorded that Ramban personally used the lion-amulet, an example of an astrologically based talisman. Ramban’s action dovetailed with his position that as long as no idolatrous practice takes place, one may employ means of divination or sorcery to effect a cure, even in a case where one’s life is not threatened.

7. ‘Sefeika de-oraitta le-humra’

If one is in doubt as to the application of a Torah law one has to adopt the stricter view. However, if one is in doubt as to the application of a rabbinical law one has to adopt the lenient view.

What is the mechanism by which ‘sefeika de-oraitta le-humra’ operates ?

We have a fascinating debate between Rambam and Ramban as follows:

Rambam’s view is that ‘sefeika de-oraitta le-humra’ is a rabbinical law. According to Torah law any doubts should be resolved leniently. This is also the opinion of Ra’avad.

Ramban however, states that ‘sefeika de-oraitta le-humra’ is itself a Torah law