Saturday, September 2, 2017

chanuka - Why do we celebrate Chanukah?


The more I read about Chanukah, the less I understand why we celebrate the holiday. The victory, as I understand it, was costly and very short-lived. Yes, the Temple was restored, but only to be destroyed ~232 years later, perhaps as the result of nationalistic tendencies that developed during the Hasmonean period. So Chanukah to me seems like the beginning of the end of the Second Temple era. It's fun but I struggle to enjoy it for that reason. What am I missing?



Answer



A Chanukah Shiur by Rabbi Joseph B. Soloveitchik, delivered at Moriah Synagogue, circa-1950, transcribed by Rabbi Nisson E. Shulman, explains the meaning of Chanukah and shows that Chanukah itself is basically a "hidden" celebration. We speak of the fight against the Syrian-Greeks, but that was not the main battle. As with many of the trials, tribulations and struggles of our people, the main fight was against our brethren. While the "outside" political victory was short lived (and betrayed by the Hasmoneans themselves), the real victory was permanent and continues today as we celebrate bris milah, shabbos, and rosh chodesh.



The problem of Chanukah was not destruction, but defilement, tum'a; tim'u kol hashemanim [=they defiled all the oil (a quotation from Maoz Tzur)]. Kesheamad malchut Yavan? Lohi, ela kesheamdu hamityavnim... [="When the Greek kingdom rose" (a quotation from liturgy)? No, when the mityavnim, Hellenists, rose]. But our rabbis sought to hide this as much as possible because dibru belashon nekiya [=they spoke with clean language].


Alma deisgalya [=the exposed world] was the war against the Greeks. Alma deiskasya [=the hidden world] was the war against the Hellenists.



So why don't we see this in the texts? We do, but we must lift the cover, since our sages did not want to speak evil about the Jews, even about the wicked ones, and so they hid the real story between the lines.


The whole story of Chanukah was euphemised. This is particularly apparent from the prayer, Biyemey Matityanu... The excessive repetition expresses it very well. "You, in Your great mercy, stood by them in the time of their distress; ravta et rivam - you fought their battle". More explicitly, "danta et dinam - you judged their case." Do you want us to be even more explicit? "You delivered the strong into the hands of the weak". Even more explicitly? "The many into the hands of the few". Still not satisfied? "The pure into the hands of the impure". Do you, then, demand an even more explicit statement?" Very well, but we say it sadly and very reluctantly, reshaim beyad tzadikim, vezeidim beyad oskei Toratecha" [="the wicked into the hands of the righteous and the sinners into the hand of those who involve themselves with Your Torah"].


From the time the Jews re-entered the Heychal [=main room of the Temple], the war against the mityavnim was virtually won, and mityavnim were nevermore in the majority. So this is an eternal miracle. That is why we still celebrate it....



UPDATE Note the rashi in Beshalach about "chamushim" points out that 80% of the Bnai Yisrael died before the Exodus to enable it to occur. This was about a millenium before the Chashmonaim so we see that the problems can recur. However, since the days of the misyavnim, we have not been in as perilous a situation (though it may be since we are in galus and they have never had such political power again). Even in the days of the "Enlightenment" and the attempts by the "secular" to destroy Judaism, they have not been in a position to force the destruction of Judaism (even seeing what has happened on the modern college campuses).


grammar dikduk - כּרְעוּתֵהּ (with a dagesh in the כּ) or כרְעוּתֵהּ (without the dagesh) in Kaddish?


Kaddish starts: יִתְגַּדַּל וְיִתְקַדַּשׁ שְׁמֵהּ רַבָּא. אמן:  בְּעָלְמָא דִּי בְרָא כִרְעוּתֵהּ


The siddur HaGr”a has כּרְעוּתֵהּ (with a dagesh in the כּ) and all my other siddurim have כרְעוּתֵהּ (without the dagesh).


Please explain the difference in meaning.



Answer



The general rule is that letters "בגד כפת" do have a dagesh when they appear in the beginning of a word, unless the word follows a word that ends with one of the vowels (אהוי), and there's a contextual connection between the two words (for example, "אחרי כן").


So here, by saying "כרעותיה" without a dagesh, you are actually saying that the two words "ברא כרעותיה" are connected, which means "[that He has] created according to His will".



This sounds right, but the Vilna Gaon actually says that the "כרעותיה" is not connected to "ברא", but to the beginning of the kadish ("יתגדל ויתקדש... כרעותיה") - i.e. that He will be praised according to His will. So there should be a slight pause between "ברא" and "כרעותיה", and therefore the "כ" has a dagesh.


Notice that a proof for the Gaon's way is the following prayer we say on Shabbat:



עַל הַכּל יִתְגַּדַּל וְיִתְקַדַּשׁ וְיִשְׁתַּבַּח וְיִתְפָּאַר וְיִתְרומַם וְיִתְנַשּא שְׁמו שֶׁל מֶלֶךְ מַלְכֵי הַמְּלָכִים הַקָּדושׁ בָּרוּךְ הוּא. בָּעולָמות שֶׁבָּרָא הָעולָם הַזֶּה וְהָעולָם הַבָּא. כִּרְצונו וְכִרְצון יְרֵאָיו וְכִרְצון כָּל בֵּית יִשרָאֵל.



The source for this prayer is Sofrim 14, 12, where it would seem that it couldn't be that "וכרצון יראיו" is connected to "ברא", but to the first part of "יתגדל" etc.


Sources:



Friday, September 1, 2017

computational chemistry - What is the dataset with the largest number of molecules?


In computational chemistry we often apply techniques to all molecules of a "dataset". Recently it was asked which dataset contains the largest molecules, and a user accidentally misinterpreted this as asking for the dataset with the largest number of molecules: Datasets of Large Molecules


This question now gives that user an opportunity to give their answer here.




acid base - How does one tell if a specific molecule is acidic or basic?


Let's take the $\ce{KOH}$ molecule into account. I know it is a base from literature, but how would one go about determining if a molecule is acidic or basic simply based on the structure of the molecule? How about amphoteric?


Also, I understand that there are two complementary systems - Lewis and Brønsted-Lowry theories. How do they work and how do they fit together?




organic chemistry - Birch Reduction of Benzene


According to my Organic Chemistry Textbook:



Benzene can be reduced to 1,4-cyclohexadiene by treating it with an alkali metal (sodium, lithium, or potassium) in a mixture of liquid ammonia and an alcohol. This reaction is called the Birch reduction.


enter image description here



Why the conjugated 1,3-cyclohexadiene is not formed in this reaction (as conjugated molecules are more stable)?



Answer




According to the article on Birch Reduction on the Organic Chemistry portal:


The question of why the 1,3-diene is not formed, even though it would be more stable through conjugation, can be rationalized with a simple mnemonic. When viewed in valence bond terms, electron-electron repulsions in the radical anion will preferentially have the nonbonding electrons separated as much as possible, in a 1,4-relationship.


http://www.organic-chemistry.org/namedreactions/birch-reduction.shtm


hashkafah philosophy - Does God benefit from our keeping of the Mitzvos?


Does Hashem benefit from mankind doing the commandments of the Torah?



Answer



The Ramban states in Devorim (Perek Kof Beis, Pasuk Vov) that "there is no benefit in our keeping of mitzvos to the Holy One blessed be He." One cannot "benefit Him" or "harm Him" through the keeping or not keeping of mitzvos. He states further that our "words of praise and remembrances of his miracles are considered as nothingness and emptiness to him. All these [mitzvos] are for our benefit alone. This is something agreed upon by all our Rabbis."


Rambam states in the Moreh Nevuchim, Book I, Chapter 55 that no change or emotion can ever be predicated of Hashem. As the Novie states in Malachi Perek Gimmel, Pasuk Vov, "I, G-d, do not change." Rambam states in the Yad, Laws Concerning the Fundamentals of our Faith, Perek Alef, Halacha Yud Alef, "and He does not change, for there is nothing that can cause change in him. There does not exist in him... anger or laughter, happiness or sadness…" It is certainly clear from the Rambam and Ramban that we cannot say of the Creator that he is at one time sad, and at another happy. He, being perfect, does not change ever. We cannot effect him or change him no matter what we do, whether we are righteous or evil, whether we pray or don't pray.



Based on the above two Rishonim, it would seem that we cannot in any way benefit or change God with the performance of the commandments in the Torah.


halacha - Does non mevushal wine make the vessels containing it treif?


As per halacha and many other questions here, non-Jews touching (etc.) non mevushal wine can cause the wine to become non kosher.


Does this have any effect of the vessels holding the wine, kashrut-wise?



For example, say you bring non mevushal wine to the table at a kosher hotel, and then a non Jewish worker touches it. Are you simply prohibited from drinking that wine, or did you cause kashrut problems in the glass, and/or whatever the glass is washed with etc. etc.?


I ask about this kind of wine specifically because I thought it might be different than other non-kosher products, as it seems to me that this is not inherently un-kosher, but rather something that has become unfit for consumption due to external concerns.




periodic trends - Comparing radii in lithium, beryllium, magnesium, aluminium and sodium ions

Apparently the of last four, $\ce{Mg^2+}$ is closest in radius to $\ce{Li+}$. Is this true, and if so, why would a whole larger shell ($\ce{...