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Thought for the Day: Nine Lines of Gemara, Three Powerful Lessons in Thinking, Learning, and Teaching

There is a standard line of reasoning in logic known as reductio ad absurdum. It is usually employed when a direct proof would be difficult/impossible and it works as follows: You want to prove that some proposition is true; say, for example, that the there is no smallest, positive, non-zero, rational number. The first step is to consider the opposite; in this case, suppose that there is, in fact, a  smallest, positive, non-zero, rational number; call it x. Next, we formulate some logical implications of our supposition; in our case, divide that smallest, positive, non-zero, rational number by two; call that y. We have posited that x is the smallest, positive, non-zero, rational number, which implies that any other positive, non-zero, rational number -- including y -- is bigger than x. So by assuming that there is, in fact, a smallest, positive, non-zero, rational number, we have shown by logical inference that would mean there is a number that is both half the size and larger than th…

Thought for the Day: So... Just What *Is* The Difference Between a Miracle and Nature?

Here's the question: Just What Is The Difference Between a Miracle and Nature?

Before you start rolling your eyes (what? too late? oh well...) and thinking.... "Good grief. Miracles are supernatural; you know, abovenature! Got it, Mikey?"

Are you finished? Good; then we can proceed.
So here's one problem with that definition. If you one is not religious and/or simply an apologist, it is very easy to assert that the miracles of yore were simply the romanitification and fanitizisation of events that happened at a propitious time and were perhaps somewhat out of the ordinary that have grown into the stuff of legends. Of course, they just assert things like that without any proof or data; their argument being, "Well, obviously it didn't happen as reported. Things like that can't happen." To which I generally respond (if it seems like it might be worth my time or if I am just in a contrary mood): "Why, yes... that's why they call it a miracle. I…

Thought for the Day: When מחלוקת הפוסקים Hits the Shabbos Table

I don't think I am overstating the case to say that one cannot live a proper Jewish life without having a rav. (Some people are their own rav... the doctor who treats himself has a fool for a patient.) There are many, many, many halachic issues the depend on weighting and balancing several factors. For example: using a tea bag to make tea on Shabbos, opening soda bottles on Shabbos, carrying in a public thoroughfare on Shabbos, keeping an ice pop in the (previously unopened) plastic wrapper while eating it on Shabbos, on Shabbos. Given that there are sensitive to weighting and balancing, and given that a violation of Shabbos is so serious, and given that enjoyment of Shabbos is a cornerstone of Jewish life... you very often have a מחלוקת הפוסקים in how to actually conduct oneself. Given "two Jews, three opinions", it is right on impossible to avoid differences in opinions at the Shabbos table.

So, as my small contribution to Tikun Olam, I herewith discuss some of the im…

Thought for the Day: Why It Is So Darn Important to Emphasize the Start Date of חנוכה

With out a doubt, the best part of giving a shiur is how much I learn in preparation. (The worst part, but the way, is agonizing and panic in the weeks leading up to giving the shiur making sure I have something to say that is worth the attendees time to hear.) Moreover, I find that while actually giving the shiur, ideas and thoughts that were still a bit murky come into sharp focus. Then there are questions that come up after the shiur. This TftD is in response to one of those questions.

So regarding the reason that חנוכה is the name of the holiday that commemorates our victory over the Greeks and the miracle of the one-day-supply-of-oil-that-lasted-eight-whole-days: it's because our enemies stopped bugging us on the 25th of Kislev -- חנו כ''ה/they rested ("parked" according to Google translate) on the 25th. (See Mishna Brura 670, sk 1.) I know that's not what I learned in Sunday school... shocking.

But hang on... besides that fact that the commemoration of …

Thought for the Day: The Excluded Middle of Cooking (Or Not) in a כלי שלישי

The "Law of the Excluded Middle" is one of the basic laws of logic. It means that for any proposition A, either "A" or "not A" is true. For example, let's take as our proposition that bumble bees cannot fly. The law of the excluded middle says that either it is true that bumble bees cannot fly (A), or it is true that bumble bees can, indeed, fly (not A); there is no third possibility. That principle is the foundation of many logical proofs, because it is often easier to prove (or disprove) "not A" than "A"; after which one simply invokes the law of excluded middle to claim a victory.

Understandably, the strict laws of classical logic do not apply to apply to all situations (as any man who has been married for more than an hour or two can surely testify). It doesn't mean there is anything illogical about the situation, it simply means that the over strict laws of classical logic have been applied incorrectly to the situation (a…

Thought for the Day: The License to Make Tea On Shabbos in a Vessel Thrice Removed from the Heat

The title is not entirely accurate, but: (1) if I said "twice removed", I fear many would think כלי שני/second vessel; (2) c'mon... how cool is it to be able to use the word thrice?

Besides the opportunity to use the word thrice (thrice, in you include the title and not this one, or just not including this one) in one TftD, I have a more serious reason to write about this. Namely, my rush to incorrectly tell someone that, "Of course the Mishna Brura says you can make tea in a כלי שלישי! It's in that long paragraph where he describes how to make tea on Shabbos." I, in my arrogance did not bother to double check. My friend (still even after this), though, did. Thank goodness.

So... the Mishna Brura has a long paragraph (Siman 318, end of s.k. 39) starting by declaring as obvious to the poskim that making tea is a cooking process, for which one would transgress a capital offence if done on purpose and with intention. The Mishna Brura then decries the lax attit…

Thought for the Day: Earliest Time to Light Chanuka Candles is Probably Later Than You Think

This is yet another reason why you need a rav.

A close chaver directed my attention to the third Mishna Brura to siman 672. The Shulchan Aruch there says that if you are really busy/preoccupied and need to light Chanuka candles early, then you can light from פלג המנחה. The Mishna Brura notes that the hour and a quarter is measured in שעות זמניות/hours adjusted for the day length. I looked back to my friend wondering what he wanted so show me. He directed me to look again (Baruch HaShem, my friends are patient with me). Sure... The Mishna Brura notes that פלג המנחה is one and a quarter hours before צאת הכוכבים/night fall and the hours are determined by the length or shortness of the day; that is, שעות זמניות. Wait... backup... before צאת הכוכבים/night fall?! We nearly always means before שקיע/sundown; not צאת הכוכבים/night fall! Right, replied my friend; what do you make of that?

The Mishna Brura is not at all shy about mentioning the different ways of calculating פלג המנחה, so that fa…

Thought for the Day: Our Attitude Toward Evil Doers

In parashas תולדות, we are told of one of the most difficult tests for our illustrious patriarch, Yaakov Avinu. Yaakov is the ultimate איש אמת/man of Truth, and he is given the task of subverting his father's plan to give the brachos to the evil Esav. Why Yitzchak Avinu wanted to give the brachos -- which would have been a horrific disaster, and why HaShem wanted him to be put in a position where he needed to be tricked by Yaakov Avinu to do the right thing -- and for which Yitzchak Avinu was very thankful, and how Rivka Imeinu knew that and what to do are all very, very interesting topics. All very, very far outside the scope of this TftD.

I want to focus on a single point. When Esav learns of the subterfuge he was devastated; וַיִּצְעַ֣ק צְעָקָ֔ה גְּדֹלָ֥ה וּמָרָ֖ה עַד־מְאֹ֑ד/he howled a very, very great and bitter cry (B'reishis 27:32). (Why it meant so much to him is also outside the scope of this TftD.) The medrash says that Klal Yisrael were punished for causing Esav to …

Thought for the Day: You are Always Allowed to Daven for Yourself... Even for a Fly

I have, Baruch Hashem, bli ayin hara, puh-puh-puh, several very bright and adorable grandsons. I have one in particular who has an incredible eye for details. He recently told me that he had a question on Chumash, parshas Lech L'cha; the battle of the four kings vs the five kings. I told him to get a chumash and show me. As he was headed to the Mikra'os HaG'dolos, I redirected him to a regular chumash. (I mean, he's only seven. How complicated could this be?) He showed that in 14:2 and 14:8 the verses tell me that one of the kings was from Bela, which is now called Tzo'ar. Verse 14:3 says that they engaged in the battle in the valley of Siddim, which is the Dead Sea. Verse 14:8 also mentions that the battle was in the valley of Siddim... but does not mention that the valley of Siddim is the Dead Sea in that second verse. In all innocence, he asked why the new name was repeated for one place but not for the other.  I sent him back for the Mikra'os HaG'dolos.…

Thought for the Day: The Power of the Community, Even in Hypotheticals

When I was younger and would express "but if" questions, my father would usually answer, "If a frog had six shooters and a ten gallon hat, then he would be a Texas ranger." As I got older, my "but if" questions got more sophisticated, and my father's response got more colorful. I am going to stick with the frog/Texas ranger response; thank you very much.

The truth is, though, that hypothetical situations can be used to reveal insights about real situations. Physicists use thought experiments (the real physicists use "gedanken" experiments; "frummer than thou" permeates all walks of life) to explore the consequences of physical theory. Recently, to my extreme delight, I learned of a situation where the hypothetical is used to drive practical halacha.

The pre-setup: We do not daven a regular weekday שמונה עשרה on Shabbos and Yom Tov. This is not because we have no need of such things as health, livelihood, in-gathering of the exiles …

Thought for the Day: Rabbinic Injunctions -- A Labor of Love

Nearly 30 years ago, when I first encountered Orthodox Judaism as a serious life style choice that threatened to seriously undermine my complacency with my Jewish identity, I approached the anticipated debacle with the many extremely cogent arguments for my point of view based on the Torah itself. I confidently met with the rabbi and was ready to do battle. Then I discovered the תורה שבעל פה/The Oral Torah. That was the first blow to my world view, but I was not out of the fight yet. Then I learned of the Rabbinic injunctions and the מסורה/the careful and meticulous transmission of the entire Torah -- Written with Oral, packaged in Rabbinic wisdom. Sigh... that was the knock out punch and here I am today.

In he Maharal's essay on Chanuka, נר מצוה, he explains the necessity and function of Rabbinic injunctions. More than that, the Maharal addresses one of (for me) the most difficult facets of Rabbinic injunctions; חמורים דברי סופרים יותר מדברי תורה/Chazal were often more jealously …

Thought for the Day: The Torah Demands and Commands That Do Not Unnecessarily Inflict Suffering on Any Living Creature

There is what people think of when the hear the word "work" and there is what the word "work" means in the context of physics. For example, suppose you picked up a bowling ball in the morning, carried it with you all day, then put it down that evening precisely in the place from which you picked it up. You might feel like you've been through the wringer, but -- according to the definition of work in the context of physics -- you have done zero work. While that may sound surprising, it is not difficult to explain why the word "work" is appropriate in both of these contexts. It is, however, outside the context of this TftD.

I bring this up, because I'd like to discuss the Torah prohibition of צער בעלי חיים. Now, if you paste that into Google Translate, you'll get: Cruelty to animals. Not a bad translation of those words from Modern Hebrew into American English, but not a great rendition of what the Torah prohibition of צער בעלי חיים really means…

Thought for the Day: Any Financial Obligation is a Loan in Halacha

Mathematics is the language that we use to express physical law. As a graduate student in the physics department, therefore, it was important to know a fair amount of mathematics. We (the physics department) and they (the math department) each had a series of classes called "Mathematics for Physicists". I, of course, feeling that taking such a class was beneath my dignity, took the same topics in math classes designed for mathematicians. After all, I reasoned, I'd rather get the fundamentals straight than some watered down elixir. I worked harder in those classes than any of my physics classes. Not that the material was intrinsically more difficult, but that mathematicians just think differently that physicists.

I publicly admit that my filing of a prozbul every seven years before Rosh HaShannah is largely pro forma; my heart isn't really in it. I mean, after all, I do not own a bank; nor am I someone that anyone would come to for a loan. I think for the same reason,…

Thought for the Day: More vs Deeper/Sharper/Beautifuler

First, a lesson in modern physics. There are many measurables that we use to characterize a physical object and its motion through space-time. Among these are mass, position, velocity, energy, charge, etc... etc... etc. Among these are groupings known as canonically conjugate variables: location/momentum (mass times velocity), time interval/energy transition, and more. The cool thing that was discovered with the age of modern physics in early 1900s was that the more precisely you measure one member of the pair, the more uncertainty you create in measuring the other member. Suppose, for example, you measure very precisely the position of a proton at one moment. You won't be able to predict where it is the next moment because you created an inherent uncertainty in its momentum (and therefore velocity). The universe just puts hard limits on what it will allow us to know about it.

"They" (you know who they are... the same ones who call it dope) say something like that about …

Thought for the Day: Consensus By Greater Majority Beats Consensus By Sharper Majority

I closed my Facebook account yesterday. I had very little reason for it in the first place, mostly as a venue to distribute TftD sort of passively-aggressively. However, two things tilted the scales in favor of breaking off relations; both regarding the reaction I saw to the horrifying events in Pittsburgh this last Shabbos, May HaShem extract vengeance for the innocent victims. One reaction was people barely referencing the event itself, but using the opportunity of a juicy news story to further their political agenda. Folks from all ends of the political spectrum (unfortunately, in America today politics only has "ends" with no meeting ground for meaningful discussion) used the event that way. I was sickened by that. I also, though, saw that a rav had posted a video of another rav commenting on the event. The posting rav strongly disagreed with the message in the video, which he stated while still keeping a respectful and professional demeanor. A comment on the post, thoug…

Thought for the Day: Magnifying vs Beautifying a Mitzvah

Shabbos candles and Chanuka candles are both נר מצוה/mitzvah candles. Being a נר מצוה, one is not allowed to use it to light an ordinary candle; nor even a match with the intent to light another נר מצוה. What about lighting one נר מצוה directly from another? Of course there are opinions all over the place. However, when the halachic dust has settled we are left with the following: You are allowed to light one Shabbos candle from another, but one may not light one Chanuka candle from another.

The correct response to that p'sak halacha is: Huh!? I know that is the correct response, as the Biur Halacha (263:1, d.h. שתי פתילות) asks the question in a surprised tone of writing. (Albeit more eloquently than simply, "huh!?")

Of course on Chanuka, we have a halachic basis for how many candles we light each night: The number of candles one lights corresponds to the number of days we are into the Chanuka celebration; one candle on the first night, two on the second, three on the t…

Thought for the Day: Torah and Rabbinic Law/Nature and Nurture

In 1889, a natural philosopher by the name of August Weismann performed the paradigm stupid and wasteful experiment in an era and stupid and wasteful experiments. I say an "era and stupid and wasteful experiments" because the scientific method was only beginning to be developed. Most of those experiments did not record enough about the procedure to render them reproducible even by themselves, let alone another experimenter. Their data was therefore useless as a basis for drawing any meaningful conclusions. August Weismann, though, stands above the crowd and designing and executing a particularly stupid and wasteful experiment. What did he do? He cut the tails off five generations of mice in an attempt to disprove Lamarckism -- a notion (I refuse to give it the title "theory", "hypothesis", or even "conjecture") that acquired traits can be inherited.

In Weismann's own words: "901 young were produced by five generations of artificially mu…

Thought for the Day: Halacha and Medrash/Using Metal Knives for Circumcision

I was talking to a cardiac/thoracic surgeon recently. I mentioned that I had worked in a radiation oncology department as a physicist doing treatment planning. I wanted to be empathetic to the stress he must feel and said I had woken up a few times at night worried that I had made a mistake. He gave me sort of a blank stare and said, "I don't make mistakes."
Ah. Well, I do make mistakes. I know that other people also make mistakes. How do I know? There is a whole body of Jewish law on what to do when one has omitted a necessary insertion. For example, forgetting "r'tzei" in bentching on Shabbos. The truth is, though, I know people who need the opposite. They so rarely eat bread during the week that "r'tzei" seems like an integral part of bentching. For those people, I offer another halacha: when bentching during the week, you should first take all knives off the table. (Yes, even butter/table knives.) On Shabbos, though, those can remain on t…

Thought for the Day: Teaching Emuna to Generations

The parasha of Noach start by telling us (B'reishis 6:9): These are the generations of Noach; Noach was perfectly righteous in his generation. Rashi chooses to explain the simple meaning of the verse by taking some of the words out of context and fooling with the punctuation (Rashi is quoting a Chazal, so he is on solid ground, of course): "These are the generations of Noach: Noach." -- to tell us the main generations/progeny of a person is his good deeds.

Without doubt an important and insightful exegesis by our Sages, of blessed memory. However, Rashi (as the rav himself says several times) is to explain the simple/apparent meaning of the verses. How does this qualify for "simple/apparent" meaning? I know that is a good question, because the Gur Aryeh asks it. I know the Gur Aryeh asks the question because a friend made that the cornerstone of his speech at sheva brachos for a mutual friend of ours last night. I was really looking forward to hearing the answe…

Thought for the Day: Is Free Will Entangled?

Catchy title, no? If you were a physicist, you'd be deeply amused by my wittiness. If you are not, you can at least be amused at how witty I think I am being.

Here is the core issue: We humans are the unique beings in Creation who have unencumbered free will. That is, in fact, what the Torah means when it says that man was created in the image of his Creator. (I am oversimplifying a bit; but really just a bit.) The question is whether we can each make our own decisions independently, or do they need to mesh together?
I should note at this point that free will is not anarchy; if I decide to jump up, I am going to follow a relatively ballistic trajectory until I land. I can't decide at the apex of my trajectory to change directions or just hover; my trajectory is a consequence of -- and therefore an integral part of -- my initial decision. The most dramatic way to phrase this question is: If Bob murders George, has Bob's free will choice of murder just interfered with George…

Thought for the Day: Making Instant Coffee on Shabbos is an Outstanding Lesson in Halachic Reasoning

I know this may come as somewhat of a shock, but the singing ("nigun", for my FFT [frum from Tuesday] friends) part of the worship service is not really my "thing". Baruch HaShem, the Aguda accommodates even recalcitrant misnagdim such as I and provides a plethora of divrei Torah -- in English, Hebrew, and even Yiddiush available to be studied during permissible intervals. Such as extended chazanus for Lecha Dodi. (One might argue that I seem to consider any singing -- especially responsive -- as extended chazanus. One might be correct.)

I usually read something from the Business Halacha Institute, which has a nice story to go along with an interesting monetary issue. I learn something and I also have a ready discussion for the Friday night table. This Friday night, though, a young man walked around distributing copies of the CRC Kosher Consumer, Sukkos Edition. As this has never happened before, I figured that HaShem was sending me a message and so I better read t…

Thought for the Day: Yom Kippur is Annual Spiritual Inventory and Training

I scheduled by annual physical for the morning of Erev Yom Kippur. I certainly wish that I had thought to do that because I wanted to take care of my physical judgement day to parallel my my spiritual one, but it just happened to fit into my schedule. Ah well; maybe next time I'll have better kavanos.

There are two questions that arise every year; one on the front end of Yom Kippur, and one on that back. On the morning before Yom Kippur -- after almost two weeks of סליחות/extra prayers specifically targeted at arousing the Creator's trait of mercy (as opposed to strict justice) -- we end with just a whimper of a prayer; abbreviated service and not even a token תחנון. On the back end -- after 25 hours of prayer, supplication, and fasting; raising ourselves to the level of completely spiritual beings -- we drop immediately into our weekday evening prayers, which includes a plea for forgiveness of our sins; hang on.... didn't we just achieve complete forgiveness and atonement…

Thought for the Day: Do תשובה One Day Before You Die

Here's some physics humor for you: What do you do if you are in a falling elevator? Wait till you are one foot from impact, then jump as hard as you can! [It's physics humor because: (a) it isn't funny. (b) we physicists would never tire of discussing why that wouldn't actually work. (c) That "not working" is more of a biology, material science, and engineering question; not real science.]

Here's something, though, that does work: Do תשובה -- real, complete תשובה -- even up to an including the very last moment of your life. A person who does real, complete תשובה in that last moment of his life merits עולם הבא, enjoying for eternity the sublime pleasure of basking in the radiance of the Divine Presence along with the entire community of the righteous.

That being the case... why should I do תשובה before the last moment of my life? Leave aside (for the moment) the practical question of how you would manage to know when that time is. Leave aside (for the mome…