In the first post I quoted Shut Maharshag & Shaivet Halevi, that in this case we are not concerned what a tinok may read, because we know for sure what the letters are.
I would like to pose an argument.
A. The criteria of "the reading of a tinok" is not only a measure in cases of doubt, in order to determine kashrus of a letter b'dieved, but also a positive criteria in כתיבה תמה [special and unique script] demanded m'lechatchila.
IE, the argument is; is shaylas tinok a tool limited to our need in specific cases, or a clear criteria demanded always as part of csiva tama.
Rambam Hilchos Tefilin 1:19: וצריך להיזהר בכתיבתן, כדי שלא תדבק אות לאות, שכל אות שאין העור מקיף לה מארבע רוחותיה, פסולה, וכל אות שאין התינוק שאינו לא חכם ולא סכל יכול לקרותה פסולה. לפיכך צריך להזהר בצורת האותיות, שלא תדמה היוד לואו, ולא ואו ליוד, ולא כף לבית, ולא בית לכף, עד שירוץ כל הקורא בהן
The Rambam is implicating that the script must be unique, each letter separate (mukaf gvil) not mixed with other letters, and clearly readable without stumbling in its reading. This is his interpretation of כתיבה תמה, similar to what he wrote in Peirush Hamishna Yadaim 4:5 that the script is called Ashuris because it is special that its letters are clearly distinct and not mixable.
The Rambam doesn’t explain that if (bdieved) a question arose that a tinok should be summoned, rather this was the criteria in the first place – "any letter that a tinok may not read it is pasul .. [the script must be obvious] so the reader [a tinok] can swiftly proceed".
Would we accept (as kosher) a formation of letters that the normal reader could not read? No! The objective reader for csiva tama is the tinok.
This case may resemble a known problem in the word פן that the nun by itself is definitly kosher, but standing next to the pai causes a problem, it looks a bit short. (see Avnei Nezer Orach Chaim 11, Gidule Hekdesh 32:17, Maharsham 3:253) the problem is not in the nun – but the combination, there is a problem reading this word.
These poskim maintain since each letter has its tzuras ois, it may be fixed, and there is no problem of shlo csidran – but it must be fixed.
Dovid [last week] in "Question and Havchonos Tinok topic" pointed to 2 tshuvos in Shavet Halevy. In vol. 5, 6:2 he quotes a rule that we never posul a letter based on judging it next to the other letter if it is kosher mitzad atzmo. However in vol. 6:152 he writes, that a doubtful letter (because of length) can be effected by other letters.
In general, the Shaivet Halevi follows his opinion in regard toבכור mentioned, but it would seem from the accepted position in regard to פן that at least we have a problem that should be fixed. (The problem in בכור is may we scrape away to fix or not because chok tochos).
But in truth, the case of בכור may be worse. (In the case of פן the problem is the coordination of the word, not any specific letter itself, the judgement of the nun is affected by the pai. But) in בכור the coordination of the letters causes a problem in reading the letters themselve, the caf is not for sure a caf maybe it’s the base of the mem. This resembles what I quoted from Rambam above the letters should be distinct each by itself, teaching us the law of mukaf gvil & reading of the tinok – the common issue, the simplicity of the reading – in בכור the caf and vav are not csiva tama, because they aren't distinct.
Another proof to this problem, is, from the law of correct spacing between the words that in extreme situations is me'akev. It is obvious that although each letter is perfect, the coordination of the words (and letters in each word) must also be readable.
B. One may argue, that the interpretation of csiva tama of the Rambam, is not accepted by all. It isn't quoted in Tur & Shulhan Aruch. Note the Tur OC begining ch. 32 explaining csiva tama – not mentioning what the Rambam wrote, in regard to the reading of a tinok. It seems from the later poskim, that a tinok is a bdieved measure, only if we have a specific doubt on a letter.
But note the Alfa Beisa's introduction (p. 198) ואל תדמה בנפשך כאשר התינוק דלא חכים ולא טיפש יכול לקרות שיצאת ידי חובתך [don’t mistake yourself, since the tinok may read it, you have done your obligation (in writing the letters correctly)]. This seems to accept the Rambams position, that the tinoks capability to read the script is obligatory.
See SA Harav 36 letter mem in the parentheses, (ועוד כי האותיות צריכים להיות נכרות מיד כשרואין אותן בראיה קלה ולא עד שיסתכל בהן קצת) – the letters must be obvious so the reader can easily proceed, and not that he have to hesitate to read. This sentence echos the Rambam above, and is the SA Harav's interpratation of the BY (Alfa Beisa) on mem – fitting with the assumption above that the AB accepts the Rambams position.
Definitly one may argue the SA Harav only meant here l'chatchila! But, that is in a case that after looking close the letter is readable, if it isn't readable even after looking close – the Rambams point seems to come into practicality.
C. The assumption that one letter adjacent to another doesn’t cause any problem, and each letter may be judged totaly separate, is questionable:
A known hallachic issue is, the head of a lamed entering the space of dalet, reish, caf sofit, causing them to resemble a hai. See SA Harav 32:41, MB 32:132.
The poskim debate what exactly is the problem. The Ramban explains that the lamed is violating the area of another letter, and this is considered שאינו מוקף גויל. Each letter should be separated by parchment from another letter, the parchment around the letter includes its space, so no letter touches anothers ink or space.
Other poskim hold that this isn't a problem of שאינו מוקף גויל, which only applies if the ink of the 2 letters touch, but a problem of shinui tzuras haois, is involved. This is the accepted position by the acharonim. There is a minority opinion (Shut Stam & Rav P'ealim; see reference in Oisiyos Harav p. 214) that a lamed entering the challal of a dalet, is in truth no problem, only because of mar'is ha'ayin must be taken care of.
It seems to me correct to equate these 2 cases, the caf&vav close to each other, and lamed entering a dalet. The majority acharonim that hold that the lamed may cause a shinuy tzura to the dalet, although not touching it but since it is to close to the dalet causing it to change (and in case of doubt demand a shaylas tinok), would equaly say so in the word בכור at question. The minority opinion (Shut Stam & Rav P'ealim) will hold as Shavet Halevi, that in both cases one letter isn't affected by another.
Further support for the (majority opinion in lamed, and equality to the case of בכור) I find in Kol Ya'acov 32:120 - if foreign letters entered the nun, may cause a shinuy tzura to the nun.
Obviously one will argue that the issues are different, because in the lamed/dalet or nun case there is a violation of the letters territory. But since we don’t pasken the Rambans interpretation, it seems the problem is shinuy tzura.
Although in the case of dalet, many will argue – it isn't like the case of בכור because a hai is unique that it is made of 2 pieces that are forbidden to touch, so the lamed entering the dalet made it a complete hai –
But that is exactly my point, we don’t face what the sofer meant or what the learned reader knows the truth is, or even a tinok if shown the whole picture would understand from the guf of the lamed. The MB says we cover the guf of the lamed to allow the illusion. According to Shavet Halevi since we know the truth, why do we have to test the tinoks illusion.
In any case the Kol Yaacov in regard to another ois entering a nun fits with my conception.
D. Another nafka-mina according to our argument is, a dalet that there is a nekev in the klaf covering the area of a nekuda of the hai – is this dalet kosher?
The Shavet Halevi definitly would machshir, since it is supposed to be a dalet and looks like a dalet – who cares about the nekev that isn't touching the letter!
But according to the poskim in lamed entering a dalet, I dare say this case also is questionable if it is csiva tama, who can tell in truth that this is a dalet and not a hai that his regel was consumed by a nekev – the letter is not obvious to a regular reader! (maybe it may be fixed by adding a patch under the nekev? Or this is chok tochos? )
E. Till now it sounds like I am machmir, but now I will examplify the argument in an opposite case, to show that I am equaly meikel.
What is the law if 2 letters touch causing a possible shinuy tzura – maybe turning them into another letter. For example a caf & vav touching, but don’t look at all like a mem, a nun & zayin touching, but don’t look at all like a tes, a caf & reish touching but don’t look at all like a mem – these are not far-fetched, but actualy do happen.
Many Rabbis will say it is clear that there is a shinuy tzura, there is no question to ask a tinok, because hallachicaly it has changed to the form of another letter, we don’t ask a tinok when we know for sure what [pasul] letter it is.
I think this isn't correct according the acharonim (SA Harav & MB) that when there is a hefsek (sh'aino nikar l'hedya) between the zadi's yud from its nun, a tinok may read and machshir (see my post "Hefsek Nikar le'hedya" – and we don’t claim since hallachicaly we have a nun and yud, so what does it matter what a tinok says,) we do follow the tinok – the same should be done in these cases!
They are the exact opposite cases of the zadi mentioned.