Wednesday, March 20, 2013

Zalman Shmotkin is not a Mathematician

I just got the following email from Rabbi Zalman Shmotkin
Dear Friend,

Real quick:

What do 191 people in Mozambique, 334 in Bahrain and 4,719 in Japan have in common?


They all joined more than one million unique individuals, each of whom who gleaned advice or received inspiration, meaning, community and much more, during this past week at…!

Were he a mathematician, he would have referred to the "more than one million distinct individuals." In mathematics, when you say there is a unique object having a certain property, it means there is only one object with that property. Obviously, there is not a unique person having the property of having visited If you want to assert that n objects have a certain property, and you want to make clear that you didn't count any of those objects twice, you'd say "there are n distinct...."

Consider the statment, "There is one person responsible for cleaning the house for Pesach, the housewife." This statement does not exclude the possibility that the housewife shares the responsibility with someone else. A better way to say it would be "There is a unique person...."

Consider the statement, "There are two people who are responsible for cleaning the house for Pesach: the housewife and the cleaning lady." This statement does not (explicitly) exclude the possibility that the housewife and the cleaning lady are the same person. A better way to say this would be "There are two distinct people...."

Monday, September 24, 2012

כפרות טויגט אויף כפרות

Can you imagine a ritual that would stimulate repentance less effectively than kappores? I suppose I could--if I expended great effort.

Saturday, September 1, 2012

Atheist by De Morgan's Law

There are different versions of De Morgan's law, but the basic idea is as follows:

Suppose A, B, and C stand for propositions. If it's not the case that A is true and B is true and C is true, then it is the case that either A is false, or B is false, or C is false.

To believe in standard Orthodox Judaism, you need to believe in a whole bunch of propositions: god exists, created the world, and spoke to the Israelites on Mt. Sinai; the Talmud reflects what god told Moses; etc.

By De Morgan's law, standard Orthodox Judaism would be false if only one of those propositions were false. So it's much easier for me to be right than y'all to be right.

Wednesday, August 1, 2012

What is Modern Chabad?

I have recently had the opportunity to observe Modern Lubavitchers in their natural habitat. At first I was appalled by their flagrant disregard of traditional Lubavitcher scruples. The men touch their beards and wear jeans. On Shabbos they're all in cuff links and ties (although they all wear white shirts). The women show much too much elbow, knee, and tichel. Why, even the rabbi's own daughter wears short sleeves, despite her old age of four!

But then I started thinking, af dem hut men gehorevet in Tomchei Temimim? Are clothes and hair all that distinguishes these creatures from their forebears? Here are some more subtle irregularities I have found:

ML men rarely pray with a minyan.
ML men are comfortable praying hatless, jacketless, and in pajamas.
ML families might use the same countertops and tables for both milchigs and fleishigs.
ML households buy whatever meat the kosher store sells.
ML couples vacation in Los Vegas.
When MLs invite friends for Shabbos meals, they use cloth napkins, napkin rings, chargers, and would never serve gefilte fish.
At said Shabbos meals, topics of conversation may include sports, movies, TV (presumably watched on computer screens), and prostate exams.
Many MLs use a non-Alter-Rebbe's eruv on Shabbos.

(Note: These conclusions are based on studying an extremely small sample of the ML population.)

Clearly, among the local population an insidious rot has crept into even the most deeply held of our sacred principles. On the other hand I have noticed that at the kindergarden graduation of a school at which many ML children are educated, the Rebbeim dramatically eclipsed God. So maybe these people can still claim to be Lubavitchers.

Oh yeah, there's also the small issue of stealing a rich synagogue. But that's neither here nor there.

Sunday, May 13, 2012

Searching for Truth

Today I visited the following six Crown-Heights stores looking for frozen 6-inch pie shells: Kahan's Superette, Benz's, Albany Bake Shoppe, Koshertown, Empire Kosher, and Kol Tov. Two of the stores did not carry this item. The other four all carried the same brand, namely Unger's (in packages of four). Yet, they each charged different amounts. The respective prices were, $4.19, $4.09, $3.99, and $2.99.

Can you guess which stores carried it and at which prices?

The prize for the correct guesser is a six-inch sweet-potato pie.

Sunday, April 29, 2012

Formerly Frum Peeps: Know Your Limits

Those who think they're going to save the world by attending The internet is NOT your problem to protest the big anti-Internet asifa, should first read the wisdom of Shulem Deen and Ushi Katz.

Have the OTD rabble rousers forgotten how frum people think? Sure, the secular press will love to write about them and their I-grew-up-in-a-cult horror stories, but the frummies they're trying to enlighten will never in a million years listen to them.

Tuesday, April 17, 2012

I wish I knew how to use a slide rule

From Wikipedia:

Compared to the portable electronic digital calculators that were introduced in the early 1970s, slide rules had various advantages and disadvantages.


  • The spatial, manual operation of slide rules cultivates in the user an intuition for numerical relationships and scale that people who have used only digital calculators often lack.[21] Since users must explicitly note the order of magnitude at each step in order to interpret the results, they are less likely to make extreme calculation errors; users are forced to use common sense and an understanding of the subject as they calculate. Since order of magnitude gets the greatest prominence when using a slide rule, and precision is limited only to the few digits that are normally useful, users are less likely to make errors of false precision.
  • When performing a sequence of multiplications or divisions by the same number, the answer can often be determined by merely glancing at the slide rule without any manipulation. This can be especially useful when calculating percentages (e.g. for test scores) or when comparing prices (e.g. in dollars per kilogram). Multiple speed-time-distance calculations can be performed hands-free at a glance with a slide rule.
  • Other useful constants such as pounds to kilograms can be easily marked on the rule and used directly in calculations.
  • A slide rule does not depend on electricity or batteries.
  • The principle of operation of a slide rule can be demonstrated with a pair of hand-made paper scales.
  • A slide rule displays all the terms of a calculation along with the result. This eliminates uncertainty about what calculation was actually performed.
  • A slide rule is physically more durable than an electronic calculator and is impervious to moisture and immersion in water.

The professor who taught me physics was from the slide-rule generation. He could do calculations like sin(4)/1.76 in his head.