There is a tendency in parts of the Torah world to err on the side of caution in all halachik matters and take on the more stringent opinions in all areas of halacha.
On the other hand, there is a tendency amongst other sectors to constantly search for  leniencies, picking and choosing the easier opinion in each area of halacha.
Are either of the above policies legitimate, or is one perhaps required to choose one or more recognized halachik authorities and follow their views in every area of halacha, irrespective of whether they are lenient or stringent?
On the previous daf, we recorded a dispute between Rav and Shmuel regarding how to close off a מבוי מפולש (alley open to the public domain at both ends.)
Rav ruled leniently like the Tana Kama in the beraisa and held that a צורת הפתח (form of an entrance) on one end and a pole or beam on the other end was sufficient.
On the other hand, Shmuel ruled stringently like Beis Hillel according to Chananya, and held that a צורת הפתח was not sufficient on the one side, but doors were required.
We also saw a different dispute, also between Rav and Shmuel, regarding a    מבוי עקום (bent alley.)
Until then, we had been dealing solely with a straight, rectangular מבוי, closed along its lengths and open either on one or two ends.
This dispute, however, centered around an “L” shaped מבוי that makes a right-angled turn in the middle, but is still open at both ends.
As such, the one end is not aligned with the other, and it is unclear whether such a מבוי  is to be treated at each end as if it is only open on that end, making a pole or beam sufficient, or whether it is to be treated like a מבוי open on both ends to a public domain, and thus require one of the more stringent solutions discussed in the Beraisa .
In this case, Rav is stringent, and holds that it is to be regarded as open on both sides (מפולש), whereas Shmuel is lenient and treats it as if it is only open on one side (סתום).
When we combine both disputes, it comes out that such a מבוי does not require doors according to either Rav or Shmuel.
This is because:
1.       Although Rav rules that it is to be treated like a מבוי מפולש (open alley), he also rules like the Tana Kama that a מבוי מפולש (open alley) does not require doors on either side.
2.       Although Shmuel rules that a מבוי מפולש requires doors on one side, he rules that such a מבוי עכום is to be treated like a מבוי סתום (closed alley.)
 
Despite the fact that we have thus not found ANY authority who holds that a מבוי עכום  requires doors, the Gemara tells us that there was such a מבוי  in the city of Neharda, Shmuel’s home town, and the authorities treated it with the stringencies of both Rav and Shmuel, requiring doors on one side!
This means essentially that they “collected” the stringencies of both, treating it like an open מבוי in accordance with Rav, and requiring an open מבוי to have doors in accordance with Shmuel.
The Gemara is extremely bothered with this approach of collecting חומרות (stringencies,) due to a Beraisa that focusses on general principles applying to disputes between בית הלל and בית שמאי.
The Beraisa rules that the law is in accordance with Beis Hillel in all cases. Yet, one is permitted to choose which of them to follow (the Gemara later explains that this was only before the בת קול  (voice from heaven) that proclaimed that the law is always like Beis Hillel, or according to the view of Rabbi Yehoshua who did not accept the authority of voices from heaven, or that this statement refers to similar disputes amongst later sages that have not yet been resolved.)
The Beraisa, however, condemns those who rely on the leniencies of both of them, calling them “wicked,” and mocks those who follow the stringencies of both of them, applying to them the verse הכסיל בחושך הולך (“the fool walks in darkness”- Koheles 2.)
On today’s daf, 2 approaches are given to explain how the authorities in Neharda had not behaved like “fools” by being stringent like both opinions:
1.       Rav Nachman bar Yitchak is of the view that in practise, even Rav would not be lenient and accept only a צורת הפתח, a claim made already by Rav Huna.
2.       Rav Shizvi seeks to explain this even according to the view of Rav Ada bar Ahava that Rav was indeed lenient in practise. He interprets the Beraisa’s application of the term “fools” to those who practise the stringencies of both houses in a far more limited fashion.
He claims that this only applies when the two disputes are inter-connected, with the lenient view in the one case logically requiring a stringent view in the other, and vice versa.
Where the two debates are completely independent of one another, there is no issue with practicing the stringencies of both.
 
To support the second approach, Rav Shizvi brings the case of the “spine and the skull,” discussed in a Mishna (Ohalos 2/3)
This Mishna deals with the bones of a corpse that are considered like the whole corpse itself and cause everything in the same אהל (covered area) to become impure.
In contrast, most bones on their own do not cause such impurity, and only cause impurity to things that touch them.
It is universally accepted that the whole spine and whole skull, being the most essentially bones of the body, are treated with the stringencies of the body itself, and make everything under the same roof of them impure.
If the spine or skull is no longer whole, however, they are treated more leniently like any other bone.
There is a dispute between בית הלל and בית שמאי regarding how much of the spine or skull needs to be missing for it to no longer be considered whole.
Regarding the spine, בית שמאי holds that unless at least 2 vertebrae are missing, it is still considered whole and the more stringent rules of impurity apply. בית הלל, on the other hand, hold that as soon as one vertebrae is missing, the spine is no longer considered whole and the more lenient rules of impurity apply.
Regarding the skull, בית שמאי are once again stringent and hold that it still considered whole unless enough is missing to cause death in a living person.
בית הלל once again are more lenient, and say if the amount normally removed by a doctor’s drill (possibly in therapeutic  surgery) from a live person is missing from the dead man’s skull, it is already considered incomplete.
Rav Shizvi then refers to the ruling of Rav Yehuda in the name of Shmuel that the same criteria apply to the laws of טריפות (terminally injured animals.)
Missing pieces in the spine and skull before slaughter are counted amongst the terminal injuries that render an animal non-kosher even after proper slaughter.
In order for it to be considered “incomplete” and thus non-kosher, בית שמאי use the more stringent criteria they applied to a corpse, essentially making it harder for it to be considered non-kosher. This turns out effectively to be a leniency in the rules of kashrus.
בית הלל in contrast, use the more lenient criteria they use to release the spine and skull from the more stringent laws of impurity, in effect making it easier for the animal to be considered non-kosher, and thus creating a stringency in the laws of kashrus!
This means that in this case, a leniency in one area of halacha, namely impurity, logically requires a corresponding stringency in a different area, namely the laws of kashrus, and vice versa.
Thus being stringent in both areas, and applying the stringent laws of impurity to a spine missing only one bone, but also considering an animal with such a spine to be non-kosher, is logically inconsistent, as is applying the lenient laws of impurity but also considering it to be kosher.
In such cases, says Rav Shizvi, being stringent like both opinions is logically inconsistent and thus foolish.
A generally cautious and stringent approach to halacha in which the stringencies of different authorities are adopted is thus not considered like a “fool walking in the darkness”  according to his interpretation of the Beraisa, unless it leads to logically inconsistency in one’s behaviour.
It is not stringency per se that is the issue, but logically inconsistent behaviour.

A spine missing one vertebra is either considered whole or not, but cannot be both whole and incomplete.

In order to develop a broader approach to this issue, a number of questions need to be raised, among them:
1.       IS Rav Shizvi’s interpretation of the Beraisa only brought in order to reconcile Rav Ada bar Ahava’s view that Rav was lenient in practise regarding a צורת הפתח in a מבוי מפולש, but Rav Nachman bar Yitchak would still prefer the original and  simpler interpretation of the Beraisa that considers collecting stringencies in general to  be a foolish and dark approach?
2.        If this is not so, we would need to explain why Rav Nachman bar Yitchak doesn’t make the obvious distinction that Rav Shizvi makes and instead chooses a view of Rav that is subject to debate.
3.       If Rav Nachman bar Yitchak indeed favors the original and simple approach, do we accept his broader view of the “fool in the dark” or the more limited interpretation of Rav Shizvi?
4.       If Rav Shizvi’s distinction is to be accepted, does this apply only to the Beraisa’s mockery of the chronic מחמיר  (one who is stringent) or does it also apply to the Beraisa’s condemnation of the chronic מקיל   (one who is lenient.) On the one hand, he only makes the distinction regarding stringency, but the need for consistency within the wording of the Beraisa seems to indicate that it applies equally to leniencies. If this is so, he would see no “wickedness” in “collecting” leniencies from different authorities, so long as they are not logically inconsistent with each other.
 
 
Answering these questions requires a thorough study of all parallel and related sugyos  and the Rishonim who comment on them. As this is way out of the scope of this post, we shall have to wait for future opportunities to revisit this topic!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.