Saturday, 30 November 2019

Leaving Eretz Yisrael


In the global society that we live in, for many it is hard to come to terms with a prohibition which may 'imprison' us in one country. Even among those who were born in Eretz Yisrael, there are few who have never left.

In addition, for most of the last 2,000 years, for most of Jewry there was little practical ramification to this prohibition, and as a result the halachic literature on the topic was limited. Here I will try to clarify what exactly is included and why. There are apparent contradictions in this regard between at least three different passages in the gemara, which will need to be resolved.

1) Making a Living – Bava Basra 91a

The gemara quotes a Beraisa which says that we may not leave Eretz Yisrael unless there is a famine so bad that two se'ah (roughly 16 litres) of flour costs a sela (a silver coin weighing roughly 19g). R' Shimon argues that if one is able to buy, he must not leave even under these circumstances. Elimelech, Machlon and Chilyon all were punished for not heeding this requirement.

Later on, the gemara qualifies that those who are not able to earn money may leave, however cheap food may be. This 'leniency' is possibly the primary justification for living outside Eretz Yisrael to this day, as many of those who were educated outside of Israel would find it difficult to find a job here.[1]

Most of the rishonim assume that the halacha is not in accordance with the strict view of R' Shimon, and in times of severe famine it is permitted to leave, if strongly discouraged.[2] However, even according to this, from this gemara, the only dispensation that appears to be given is for those in some kind of financial difficulty.

2) Mitzvos versus Impurity – Avoda Zara 13a

Elsewhere it seems clear that there are some other reasons for which it is permitted to leave the country. Kohanim have an additional problem with being outside Eretz Yisrael – Chazal decreed that all of Chutz La'aretz is impure.[3] This would normally mean that kohanim cannot leave Eretz Yisrael,[4] although a beraisa gives 3 reasons for which a kohen is allowed to become 'contaminated' with this kind of impurity:

  • To retrieve one's money or property in court.
  • To learn Torah.[5]
  • To get married.

It seems rather strange that these reasons are not mentioned at all by the first gemara quoted. Furthermore, the implication here is that these special circumstances are only necessary in order to allow a kohen to leave Eretz Yisrael. The impression given is that a regular Jew could leave even without such a pressing need.

3) Deserving of Death – Kesuvos 111a

A person once asked R' Chanina if he should leave Eretz Yisrael in order to perform the mitzvah of yibum, after his brother died there leaving a widow and no children. R' Chanina answered rhetorically in the third person: "His brother married a Kuthean[6] and died, Baruch Hashem who killed him! Now he (the questioner) should follow him?!"[7]

Here R' Chanina warns someone (not specifically identified as a kohen) not to leave Eretz Yisrael even for the purpose of marrying and performing the extra mitzvah of yibum.

To summarise, the different impressions one gets from the 3 sections of the gemara are:

1) It is permitted to leave only out of financial necessity.
2) One may leave in order to perform one of various important mitzvos, including getting married.
3) One may not leave in order to get married.

Gemara 2) seems to be contradicted by both 1) and 3).


Tosfos[8] raise the issue of the contradiction between 2) and 3), and are forced to explain that the dispensation to leave Eretz Yisrael to marry in 2) is only temporary – the plan must be to return after the mitzvah is done. In 3), the enquiry was about leaving permanently.

This explanation appears rather difficult, as in neither 2) nor 3) does the gemara specify whether the intention was to return or not. As in both places the gemara is dealing with someone wanting to leave in order to perform a specific task, I believe it is fair to assume that in both instances the leniency is only regarding leaving temporarily. Furthermore, getting married would not appear to justify leaving Eretz Yisrael permanently, as the halacha entitles either spouse to insist on moving to Eretz Yisrael.[9]

The Rambam makes the same distinction as Tosfos, although he seems to do this based on 1) and 2) above as opposed to 2) and 3). He writes that while it is permitted to leave Eretz Yisrael temporarily in order to learn, marry etc., (2), leaving permanently can only be justified out of severe financial need (1).[10] The grounding for this approach in the gemara is clearer to me – the global conditions such as famine and economy described in gemara 1) have no clear endpoint and one who leaves for this reason cannot usually make clear plans to return.

If my thesis is correct, the Rambam does not accept the explanation of Tosfos regarding gemara 3). Here it was wrong to leave Eretz Yisrael even temporarily, even in order to perform yibum. I believe that in 3) there was a special reason – the late brother originally left Eretz Yisrael without any justification and bore the consequences. To honour the memory of such a person by following in his footsteps, even temporarily, is not recommended. The surviving brother may have already had a wife, and even if he didn't he would do better finding one in Eretz Yisrael.[11]

Business Trips

The remaining difficulty is the implication from 2) that a non-kohen may leave Eretz Yisrael (albeit temporarily) for reasons other than the 3 listed. The Rambam resolves this difficulty by adding a fourth reason that a non-kohen may leave Eretz Yisrael temporarily – in order to do business.9

The probable source for this leniency is a fourth gemara, dealing with the prohibition of shaving during Chol HaMo'ed. This prohibition is waived for various people who were not able to shave before Yom Tov; the tana'im dispute whether one who returns from abroad is included in this leniency. The gemara explains that all agree that for one who went on a pleasure trip there is no leniency and all agree that one who goes in order to obtain sustenance may shave on his return. The dispute is regarding one left in order to 'make a profit,' with R' Yehuda ruling stringently and the Chachamim permitting.[12] The halacha follows the Chachamim.[13]

The dispensation given for one who returns from a business trip is a clear indication that such trips are permitted. The Rambam uses the same language (לסחורה) to describe such trips, both in reference to the prohibition of leaving Eretz Yisrael and when quoting the leniency during Chol HaMo'ed.[14]

Equivalent Reasons

The rishonim dispute whether the circumstances listed by the gemara allowing one to leave are exhaustive. Tosfos quote the view of Rav Achai Ga'on, that the 3 reasons listed in the gemara are relatively weak.[15] It goes without saying that it is permitted to leave in order to fulfil other mitzvos. Tosfos disagree, showing that elsewhere these mitzvos are given a higher priority than other mitzvos.[16]

The Rambam writes that the reasons listed above allowing a kohen to leave Eretz Yisrael are examples, and the same applies for similar reasons.[17] Regarding a regular Jew, the Rambam gives the four exceptions (litigation, learning, marrying and business) and does not state explicitly that these are mere examples. However, this is presumably because the leniency of leaving in order to do business is by definition wide-ranging. It would be inconceivable to suggest that leaving Eretz Yisrael temporarily is permitted for business, but not in order to perform mitzvos.

The conclusion is that for a non-kohen, leaving Eretz Yisrael temporarily is permitted for any mitzvah purpose or for anything akin to 'business.'[18] Leaving for pleasure alone would appear to be forbidden.


Rashbam writes that the reason that Chazal forbade leaving Eretz Yisrael is because leaving absolves a person of the mitzvos connected to the land.[19] Ramban explains differently, that all the hyperbole used by Chazal in relation to Eretz Yisrael is part of the mitzvah of taking possession and living in Eretz Yisrael.[20]

Following either approach, it is hard to understand why it would be forbidden to take a short trip to see some of the wonders of creation (or even the wonders of different societies) outside of Eretz Yisrael while intending to return. It is likely that the original reason that Chazal were so stringent was because in the past, plans to return even after a short period of time would often not materialise. Nowadays this seems far less relevant.

Some poskim are indeed more lenient nowadays based on this difference.[21] However, without a Sanhedrin to rescind or alter the prohibition, this is far from straightforward.[22] It is quite clear from cases in the gemara that the prohibition applies even when stepping over the border for a minute.[23]

My conclusion therefore is that one thinking about travelling out of Eretz Yisrael for pleasure should consider carefully whether this is really necessary, and whether he could not make alternative plans at one of the many potential locations inside the country. Those who are uncomfortable with the perhaps anachronistic nature of the prohibition could find comfort in the fact that nowadays there is a new reason to limit travel – doing our bit for preserving the planet by reducing carbon emissions.

[1] It is very difficult to define what level of effort a person must put in in order to overcome this problem, although for those who do not currently live in Eretz Yisrael it makes sense to be fairly leninent.
[2] Rambam, Hilchos Melachim 5:9; Yad Rama. See also Meiri.
[3] See Shabbos 15a-b for details of the various decrees. The main reason for this enactment seems to have been practical – there were many unidentified graves in Chutz La'aretz which a kohen may come in contact with unintentionally. However, see Tosfos in Nazir 54b (ד"ה ארץ העמים) who give an additional purpose – Chazal wanted to discourage us from leaving.
[4] The poskim discuss whether this applies nowadays, the Maharshal claiming that now Eretz Yisrael is no less pure than the rest of the world (commentary on the Tur, Yoreh Deah 369). See Shach, Taz and Pischei Teshuva to Yoreh Deah 369:1.
[5] The tana'im dispute whether this applies when there are rabbis in Eretz Yisrael from whom a person could learn. The halacha follows R' Yossi, who allows one to go to learn outside Eretz Yisrael even in these circumstances. The reasoning is that a person is not necessary capable of learning successfully from anyone.
[6] See Maharsha in Chidushei Agados who explains why this term was used here.
[7] Kesuvos 111a
[8] Avoda Zara 13a (ד"ה ללמוד)
[9] See Mishna and gemara, Kesuvos 110b.
[10] Hilchos Melachim 5:9
[11] See Chidushei Maharit on the gemara there, who explains similarly. The mitzvah of yibum does not obligate him to travel – it is incumbent on the widow to come to the place of the brother-in-law for yibum or chalitza (Sanhedrin 31b).
[12] Mo'ed Katan 14a
[13] See Shulchan Aruch, Orach Chaim 531:4
[14] Hilchos Yom Tov 7:18
[15] See Yad P'shuta, Hilchos Avel 3:14 who explains that this is not because learning and marrying are less important than other mitzvos, just that it is far from certain that these objectives will be met by leaving.
[16] Avoda Zara 13a (ד"ה ללמוד). The proof is from the prohibition of selling a Sefer Torah, which is only waived if the purpose is to learn or marry. However, according to the Yad P'shuta this can be resolved. Selling a Sefer Torah can raise the funds needed immediately, whereas undertaking a long journey in order to do these mitzvos is far less assured of being successful.
[17] Hilchos Avel 3:14
[18] As R' Shaul Yisraeli points out in Eretz Chemda 1:1:10, even Tosfos only limited the leniencies given to a kohen and did not discuss the law of a non-kohen. The conclusion of the gemara in Kidushin 31b also seems to be that it is permitted to leave Eretz Yisrael in order to honour ones parents.
[19] Bava Basra 91a (ד"ה אין יוצאין). This reason requires further explanation, as one is not usually obligated to ensure that he becomes liable to perform mitzvos. Furthermore, Hashem decided that these mitzvos should not apply outside Eretz Yisrael for a reason. Assuming that the reason was to highlight the importance of Eretz Yisrael, it would appear that the Rashbam has paradoxically made the means (the mitzvos) dependent on the end purpose (living in Eretz Yisrael).
[20] Sefer HaMitzvos, 'forgotten' positive mitzvah 4
[21] See Peninei Halacha, "The People and the Land," 3:9
[22] I discussed this at length in Eternal or Obsolete.
[23] See for example Gitin 76b.

Friday, 8 November 2019

Killing to save - the law of the rodef

I am sure that most readers will be aware that the Torah encourages the prevention of murder by virtually all means, including taking the life of the would-be murderer (or rodef, pursuer) when absolutely necessary.[1] Here I would like to examine the application of this 'leniency' in a variety of cases, after the following disclaimer:

The misuse of these halachos by a certain individual in recent history has led some to make discussion of the entire subject a taboo. I, however, believe that intelligent analysis of any topic is not to be silenced in any way. For those who are exceptionally sensitive to these issues at this time of year, read on at your own risk. For those who are not, don't be disappointed if what I write does not appear particularly controversial.

The unwitting pursuer

The first point to clarify is the status of a person endangering someone else's life unintentionally. The gemara tells us that if a child is about to kill someone, the child's life can (and should) be taken, without any warning (obviously, this is again only if this is the only way of saving the 'pursued').[2]

From here the acharonim infer that the main purpose of killing the pursuer is in order to save the pursued, rather than being a punishment.[3] However, even after this explanation, I have a great difficulty understanding why we are supposed to prioritise the life of the pursued over the pursuer when both are innocent. Wouldn't it be better to be passive, in the same way that we would normally kill one person in order to save another?

I have not seen anyone who addresses this question, and the only answer I have come up with myself is that in fact the gemara is not talking about a completely innocent pursuer. Although children are not usually held responsible for their actions, if a child is attempting murder we have a legitimate reason for deciding that "the blood of the victim is redder."

A corollary of this would be that if it is clear beyond doubt that the child is completely innocent, for example the 'pursuer' is a baby playing with a pistol, we have no right to terminate his life to save another.[4] The same would apply to an adult who is about to kill someone inadvertently, at least if it is clear that there is no negligence whatsoever involved.[5]

Foetal pursuers

The problem with this theory is that the gemara continues by comparing to a case where the life of a woman in childbirth is in danger, and could be saved by terminating the life of the foetus. The halacha is that as long as the baby's head has not emerged, the mother's life takes precedence. Once the baby is born, we do not "push off one life for another."

The gemara asks why isn't the newborn baby considered a 'rodef,' and therefore be killed to save the mother. This question clearly assumes that the status of a rodef can apply even to someone who is at no fault whatsoever.

The gemara answers that the usual law of a rodef does not apply in the case of the mother and baby, as "the pursual is from Heaven." Could the reasoning behind this cryptic answer be the hypothesis suggested above – as the baby has no responsibility whatsoever, his actions are not considered his own rather those of Heaven?

To my disappointment, I have not managed to find a single commentary that explains in this manner. The Rambam writes that once the baby has emerged he cannot be considered a rodef as "this is the nature of the world."[6] Apparently, the Rambam understands that a person cannot be deemed a rodef when acting in the normal way of the world.[7] One acting abnormally could be a rodef, even if they could not be expected to act with any degree of responsibility.

The Rid (Rabbeinu Yeshaya d'Trani, 1180-1260, Italy) writes that the baby is not a rodef as he is not acting on his own accord.[8] This is slightly closer to the way I would like to explain, although I believe that there is a difference. I understand that the Rid sees the baby during birth (even after the head has emerged) as akin to a stone being thrown, as his role in endangering the mother is entirely passive. If a baby was actively endangering someone, he would be considered a rodef despite not being at any fault.[9]

Indirect causes of danger

The next question is over the status of one who is not going to be the killer, but will facilitate the acts of the real murderer. If a witness to this cannot directly stop the murderer directly, should he foil his plans by eliminating the accomplice?

The answer to this would appear to be a simple yes. The gemara says that a moser (informant) is to be put to death, and quotes cases where this was indeed implemented. The reasoning is that once a person falls into the hands of an evil regime, even over monetary issues, his life will likely be in danger (this clearly does not apply to civilised governments nowadays).[10]

It is important to point out that this equation between a murderer and a facilitator of murder only applies before the murder has been committed (or if there is a danger of further murders taking place). After the fact, although a murderer may be liable to the death penalty,[11] an accomplice or even one who murdered indirectly alone (e.g. by stealing someone's life saving medicine) is not.[12] What is the reason for this distinction?

I once heard from R' Zalman Nechemia Goldberg (shlit"a) that the reason why the Torah does not obligate a person for damage caused indirectly is entirely practical. While an indirect damager (or killer) may be just as guilty as a direct one, if we had to punish indirect offenders it would be very difficult to define who exactly is considered a cause. In the end, we may have punished those with only spurious connections to the damage.[13]

This concern also exists when it comes to prevention of potential murder. However, when a human life is potentially in immediate danger, we do not have the option of simply remaining passive out of concern for what might happen in other situations. We must be decisive, and if it is clear beyond reasonable doubt that we can prevent murder, we must act. Equally, we must not make rash decisions to act without thinking it through properly.

Self-confidence and overconfidence

What happens when a person has thought out the issue properly and arrived at the conclusion that there is a rodef who must be disposed of, but no-one else seems to agree? He consults with others, hears their views but finds fault with their arguments that they are unable to address to his satisfaction. Is he supposed to defer to the majority opinion, or follow his own logic?

If we were dealing with a more 'run of the mill' halachic question, as long as there is no Sanhedrin I have written before that each person indeed has the right to 'go it alone.'[14] The same would seem to apply here, the only difference being that the severity of the issue would require more thorough consideration.

However, for technical reasons there will likely be a further difference here. Based on what we have already written, in order to classify someone as an indirect rodef and to kill him, the 'saviour' would need to be convinced that the following are all true:

1) The 'rodef' is definitely (beyond reasonable doubt) putting others in danger.
2) Nothing other than killing the 'rodef' will prevent this danger.
3) Killing the 'rodef' will stop this danger.[15]

The third condition will be much harder to fulfil if the 'saviour' is not recognised by others as preventing a real danger. As long as the 'rodef' has significant support, and even his opposition do not see him as a 'rodef,' it will likely be impossible for the one 'enlightened' individual to remove the danger alone. While one should not be scared of expressing unique opinions, one who does so should be well aware of the limits of his ability to draw others with him.

For those of us more inclined to fly in the face of public consensus, this last point is important to remember even with matters that are not an issue of life and death (or appear not to be). Individuals who act alone should usually do so only when others are not affected. Likewise, those in positions of power should respect the will of those they are representing when making far-reaching and irreversible decisions. Failure to do so often brings results that are unwanted by all.

[1] If the victim can be saved while also sparing the life of the rodef, such as by shooting him in the foot, this must be done (see Sanhedrin 57a).
[2] Sanhedrin 72b
[3] See for example Aruch LaNer, Sanhedrin 73a.
[4] See Chashukei Chemed, Sanhedrin 72b, who questions whether the baby is considered a 'rodef' here for other reasons.
[5] This may even be the implication of the language that the gemara uses, that a rodef can be killed even without warning. If he can be killed even when he is at no fault whatsoever, we would have expected the gemara to say so explicitly.
[6] Hilchos Rotzeach 1:9
[7] Although according to the Rambam there, an unborn foetus is considered a rodef even when merely following natural processes, as it is not yet a 'soul.' See also Igros Moshe, Choshen Mishpat 2:69.
[8] Piskei Rid, Sanhedrin 72b
[9] The Yerushalmi gives a different (and perhaps even more cryptic) reason not to kill the baby as a rodef – "it is not known who is killing who" (Shabbos 14:4, Avoda Zara 2:2). This presumably means that the mother is also endangering the baby as much as the baby is endangering her (although see Igros Moshe ibid. who explains that the Yerushalmi means the same as the Bavli). This also contradicts my hypothesis, stating that both the mother and baby are potential 'pursuers' despite the clear fact that neither have any guilt.
[10] Bava Kama 117a; Berachos 58a. See also Rosh to Bava Kama there, who writes explicitly that a moser is a type of rodef.
[11] If he was warned, verbally acknowledged that he will be liable to death and was witnessed by two kosher witnesses.
[12] There is some discussion about this regarding a moser (see Choshen Mishpat 388:11), although this is because of the concern that the moser may repeat his actions.
[13] He based this on the Rambam, who explains that the Torah does not accept circumstantial evidence for similar reasons (Sefer Hamitzvos, Lo Sa'aseh 290).
[15] It is not clear to me how definite one has to be about this – it would seem reasonable that one who sees someone beating another to death does not have to ensure 100% that it is not too late to save the victim.

Friday, 4 October 2019

Fasting and Affliction


Yom Kippur is unique in many ways. The aspect that I would like to discuss here is the idea of physical self-affliction, something that elsewhere in the Torah we only find in a negative way (as in the prohibitions against self-mutilation and leaving bald patches as a sign of mourning), or as something that a person can voluntarily take upon himself (as in the case of the nazir).

What is the idea behind fasting and other forms of self-deprivation? The prophet Yeshayahu tells us that the ultimate goal of fasting is 'untying the knots of wickedness' and 'releasing the crushed to freedom,' rather than merely 'bending ones head like a fish-hook' and displaying sackcloth.[1] However, the question remains as to what the actual fasting is supposed to achieve. Could we not have days of repentance without fasting, perhaps enabling some to concentrate more effectively on their prayers and self-improvement?

Furthermore, if the only imaginable purpose of fasting is to lead a person to repentance, what exactly did those who 'bent their heads like fish-hooks' think they were achieving? It is hard to believe that all of these actions were only meant as a show for others – if the general population were impressed by pretences like these, taking it as sincere worship, this would at least have meant that the majority were not worthy of the wrath of Yeshayahu.[2]

Thus, to me it is clear that these people believed that there is an inherent value to self-affliction, even without any improvement in their conduct. They were mistaken, but how mistaken is not entirely clear. The question is whether or not there is an inherent value to self-affliction for one who does meet the prerequisite of examining his ways.

Purifying the soul

The Chovos Halvavos writes that there are two levels of abstinence. The basic level is the control of one's physical desires in a manner designed to preserve physical health. Hashem intentionally made man and many animals in this way, 'causing the soul to suffer and be tested' in this world in order to purify it and 'be of the form of the angels.'[3]

There is also a unique level of abstinence, which has the purpose of 'fixing our souls' for Olam Haba. After quoting several opinions as to what this abstinence consists of, his favoured definition is abstinence from all physical relaxation and pleasure, besides what a person cannot naturally live without.[4]

Although this view did not become the mainstream in Spain, where the author of the Chovos Halvavos (Rabbeinu Bachya ibn Pakuda) lived in the 11th century, the Chasidei Ashkenaz of the 12th and 13th centuries did adopt many practices based on a similar philosophy. One example relevant to the days we are in now is the concept of 'Teshuvas HaMishkal' – its proponents say that if one had any forbidden physical pleasure, he should cause himself an equivalent level of pain.[5]

One who learns the Shulchan Aruch and its commentators in depth should see that the Chasidei Ashkenaz had a significant influence on the accepted halacha in Ashkenazi communities.[6] To this day, many say the Tefila Zaka prayer before Kol Nidrei at the start of Yom Kippur.[7] One of the more overlooked sections of this prayer contains the statement that we are 'obligated' to atone for our sins through Teshuvas HaMishkal, however we ask for mercy as we lack the strength to do so.

According to this view, Yom Kippur is the day that all of us rise to the level we would ideally be on the entire year, those unable to repeat this on a regular basis praying that this one day of self-affliction should suffice to purify our souls and prepare them for Olam Haba. It won't work without teshuva, but equally teshuva can only be complete with an element of physical suffering.[8]

The opposing view

This way of life was rejected entirely by R' Saadya Gaon (born 882 in Egypt). He criticises a group of people who distance themselves from the world in an extreme way, detailing how impractical and dangerous this way of life is. He then argues that abstinence should only be practiced in its correct place, which is when something forbidden is presented to a person.[9]

Similar criticism can be found in the words of the Kuzari[10] and the Rambam.[11] In the case of the Rambam, rejection of the idea of purification through physical suffering is fundamental – the physical can never be elevated to a different inherent state and will always have the limitations we know of.[12]

According to this, there is no inherent value to self-affliction and the people Yeshayahu was criticising had missed the point entirely. Why then do we fast on Yom Kippur? The Rambam explains that it is in order to fix our minds on repentance and complete worship of G-d, without being distracted by physical needs. Work is forbidden for the same reason.[13]

Affliction and Cessation

According to both views, it is important to pay attention to the language that the Torah uses when telling us to fast. The usual translation of the term עינוי נפש, 'affliction of the soul,' can be misleading. One thing is certain – at no time is there any mitzvah or praiseworthy practice of actively causing oneself pain.[14] The term עינוי refers to the holding back of something usually wanted, rather than to active affliction.[15] The debate is whether one purpose of this passive affliction is to cause 'active' suffering, or merely to be a preventative measure.

However, Chazal infer that another verb used in reference to Yom Kippur also relates to abstinence. The gemara learns from the extra word 'Shabbaton' that not just food and drink are forbidden – washing, rubbing oil on oneself, wearing shoes and marital relations must also be refrained from.[16]

As 'Shabbaton' means rest, or cessation, this would appear to indicate that the purpose is indeed the avoidance of distraction, rather than any inherent value to suffering. Presumably all would agree that this aspect exists on Yom Kippur, even if it is not the only reason for fasting.

On the other hand, those who deny any inherent value to self-affliction have difficulty explaining what the two different verbs used by the Torah (affliction and cessation) represent. The Rambam uses the two terms interchangeably, and it would appear that he understands that the Torah only described the 'Shabbaton' as an 'affliction' in order to clarify what it is we are supposed to rest from.[17]


Personally, here I have a conflict between the view that appears to be slightly better supported by the sources (that of the Chovos Halvavos and the Chasidei Ashkenaz) and the position that makes more sense to me philosophically (that of the Rambam). As this is ostensibly a non-halachic (or meta-halachic) issue, my aim on Yom Kippur (and the rest of the year where possible) is to achieve the right frame of mind rather than a physical purge from impurity.

Wishing all Klal Yisrael a Yom Kippur used in the appropriate way (whatever that is!) and a Gmar Chasima Tova.

[1] See Yeshaya 58:5-6 (and the rest of that section), read as the Haftarah for Yom Kippur in the morning.
[2] There is a possibility that people fasted in accordance with the practices of their ancestors, without any real thought as to why they were doing so (such a phenomenon exists today as well among the non-religious, traditional community, who tend to fast on Yom Kippur). However, the castigation of Yeshayahu implies that people attached real value to what they were doing, not just sentimental or cultural value.
[3] Chovos Halevavos, Sha'ar HaPerishus, chapter 1.
[4] Ibid. chapter 2. He goes on to explain the details of this at length in the rest of Sha'ar HaPerishus.
[5] See Rokeach (R' Elazar of Worms), Hilchos Teshuva, siman 6 onwards. This idea is one offshoot of the broader philosophy of the Chasidei Ashkenaz - the mitzvos of the Torah that obligate all only consist of the bare minimum of what Hashem expects of us. Thus they wrote extensively about additional recommended practices that are not found in the Torah or even in the words of Chazal.
[6] Although the group ceased to exist after the passing of the Rokeach, many of the talmidim of the Rokeach and their talmidim (e.g. the Or Zarua, Maharam MiRotenburg and the Rosh) were the primary Ashkenazi poskim together with the Ba'alei HaTosfos. This is likely at least one of the reasons that the Rema tends to be more stringent than the Shulchan Aruch in his rulings.
[7] This tefila was authored by R' Avraham Danzig (1748-1820, Eastern Europe), the author of the Chayei Adam, who was not known as a mystic.
[8] A possible precedent to this view in Chazal could be the practice of R' Tzadok, who fasted for 40 years in an attempt to prevent the destruction of Yerushalayim (Gittin 56a).
[9] HaEmunos v'HaDeyos, Ma'amar 10. However, it is not entirely clear from R' Saadya's words whether this rejection is for practical reasons alone, or because of something more fundamental. For similar reasons it is hard to find a concrete proof from the words of Chazal for this view – although there is plenty of criticism of self-affliction, this may be merely for practical reasons.
[10] Kuzari 2:50; 3:1.
[11] Hilchos Deyos 3:1; Introduction to Avos (Shmona Prakim) chapter 4. However, the Rambam does not share R' Saadya's view that abstinence should be only from the forbidden – see Lust - permitted  and forbidden. The common denominator between them is that physical pleasure is only negative insofar as it distracts from constructive pursuits.
[12] See Moreh Nevuchim 3:12. This is also why Olam Haba has to be free from physicality according to the Rambam (Hilchos Teshuva 8:2).
[13] Moreh Nevuchim 3:43. See also Chinuch, mitzvah 313, who adds that it would not be fitting for a servant to come to judgement in front of his master whilst under the effects of food and drink, thinking about physical things. However, against this one could argue that fasting may have the opposite effect, diverting the attention of some to their physical hunger.
[14] On the contrary, active self-harm is forbidden. See Devarim 14:1 (where this is the most explicit in the Torah) and Bava Kama 90b.
[15] Thus the same term is used by the Torah to describe nedarim, personal undertakings to abstain from certain things (Bamidbar 30:14). The same verb is used by Lavan when warning Ya'akov not to mistreat his daughters (Bereishis 31:50), and this is understood by Chazal to be referring to the withholding of marital obligations (Yoma 77a). See also Yoma 74b, where Chazal interpret this term similarly regarding the Egyptians' treatment of Bnei Yisra'el.
[16] Yoma 74a. The rishonim debate whether or not these prohibitions are Biblical or Rabbinic, but even if they are entirely Rabbinic, one can see from the word used what Chazal's intentions were when making these restrictions.
[17] Hilchos Shevisas Asor 1:4-6