Weekly Torah portion

Vectors, Spins, and Gender

Vectors, Spins, and Gender Speak to the children of Israel, and have them take for Me an offering; from every person whose heart inspires him to generosity, you shall take My offering. (Ex. 25:2) Every physics professor teaching physics 101 to freshmen spends the first lecture teaching vector algebra. Why vectors are so important? Because most quantities in mechanics (a branch of physics dealing with motion and forces) are vectors. A vector is a mathematical object that has a magnitude and a direction. For example, velocity is a vector – it shows not only how fast the object is moving, but also in what direction it is moving (it is different from “speed” which is an average velocity and is just a number). Similarly, acceleration is a vector, force is a vector, angular [...]

Jacob Meets Esau and his 400 men

And the messengers returned to Jacob, saying: “We came to thy brother Esau, and moreover he cometh to meet thee, and four hundred men with him.” (Gen. 32:7) Why does the Torah take pains to tells us the exact number of men accompanying Esau? Servants of Esau are of no particular significance. It is apparent that, by specifying the number of men in Esau's entourage, the Torah is trying to tell us something about Esau. It seems to me that Jacob understood the significance of the number 400. This number is a sum of the powers of 7 from 0 to 3: 70+71+72+73=400. This four powers of 7 hint at the lunar month that has, approximately, 28 days (4×7). The significance of this will become apparent later. 400 is a repdigit in base [...]

The Meaning of Life as Taught by Bayesian Angels

And he [Jacob] dreamed, and behold! a ladder set up on the ground and its top reached to heaven; and behold, angels of God were ascending and descending upon it. (Gen. 28:12) Rabbi Shneur Zalman of Liadi (a.k.a Baal HaTanya, or the Alter Rebbe) once remarked in Yiddish, “lieben mit di tzait” – live with the time, meaning one should live with Torah portion of the week.  Last week I was taught a lesson on how the current Torah portion affects my thinking, whether I know it or not. Last week I shared with my wife, who is a biophysicist, that while thinking about system biology, I realized that all organisms – from a single cell to multicellular organisms – are Bayesian systems. I knew that the brain is a Bayesian engine, but [...]

Second Derivative – Secrets of the Double Cave

And he [Avraham] spoke with them, saying, “…Listen to me and entreat for me to Ephron the son of Zohar. That he may give me the Machpelah (Double) Cave, which belongs to him, which is at the end of his field…" (Gen. 23:8-9) double: A house with an upper story over it. Another interpretation: because it was doubled with couples (Er. 53a) (Rashi on Gen. 23:9) In the Torah portion Chayei Sarah, Avraham purchases a Double Cave, Machpelah, as the ancestral burial plot. Almost all Biblical commentators interpret Machpelah-double to mean a cave with two chambers. Rashi takes an entirely different approach and states that the cave was known for a two-story house built on top of it. So, the word “Machpelah” (lit. “double”) refers not to the cave itself, but to the house [...]

Biblical Relativity

And the life of Sarah was one hundred years and twenty years and seven years... (Gen. 23:1) Why did Esther merit to rule over 127 countries? Said God: “Let Esther, the descendant of Sarah who lived 127 years, come and rule over 127 lands. (Esther Rabbah 1:8) The Midrash Ester Rabbah compares 127 years of Sarah’s life with 127 provinces that Esther ruled. How can one compare time with space? When the Midrash says that Adam gifted 70 years of his life to his descendant, King David, it’s understandable – a year for a year. But a year for a province? What’s the connection? Hermann Minkowski When, in 1905, Albert Einstein published his Special Theory of Relativity, it was nothing short of a scientific revolution. For the first time, Einstein showed [...]

Wellsprings from Above and Wellsprings from Below

In the six hundredth year of Noah's life, in the second month, on the seventeenth day of the month… all the fountains of the great deep were broken up, and the windows of heaven were opened. (Gen. 7:11)   In calculating the time of the dawn of Messianic revelation, the Zohar writes, And after six hundred years of the sixth thousand there will be opened the gates of wisdom above and the fountains of wisdom below, and the world will make preparations to enter on the seventh thousand as man makes preparation on the sixth day of the week, when the sun is about to set. (Zohar I, 117a) The Zohar calculates this based on the letters of the Tetragrammaton, but brings the verse from this parshah as the mnemonic: “In the six [...]

Day Six – the State of Superposition

And God saw all that He had made, and behold it was very good, and it was evening and it was morning, the sixth day. (Gen. 1:31)   The Biblical narrative of creation concludes with the above verse. Rabbi Shlomo Yitzchaki (a.k.a. Rashi) comments on this verse: the sixth day: Scripture added a “hey” on the sixth [day], at the completion of the Creation, to tell us that He stipulated with them, [“you were created] on the condition that Israel accept the Five Books of the Torah.” [The numerical value of the “hey” is five.] (Tanchuma Bereishith 1). Another explanation for “the sixth day”: They [the works of creation] were all suspended until the “sixth day,” referring to the sixth day of Sivan, which was prepared for the giving of the Torah (Shab. 88a). [...]

Shabbat Bereshit – Past, Present, and Future

In the last post, Tishrei—Past, Present, and Future, we discussed how all Tishrei holidays – Rosh HaShanah, Yom Kippur, Sukkot, and Simchat Torah – are connected by the same thread of time and, more specifically, the unification of past, present, and future. This cluster of Tishrei holidays is culminated and concluded with Shabbat Bereshit, when we start the new annual cycle of reading the Torah. Not surprisingly, Shabbat Bereshit follows the same pattern of unification of past, present, and future. The Torah starts with the creation of the world. The story of Creation, obviously, relates to the past. The word “bereshit,” means, in the beginning. The root of “bereshit" is “reshit” – beginning. Beginning, however, points into the future – to something that will follow the beginning in the future. The Lubavitcher [...]

Scientists are Clarifying Witnesses

Listen, O heavens, and I will speak! And let the earth hear the words of my mouth! (Deut. 32:1) In this Torah portion Haazinu, Moses appeals to heavens and earth as witnesses. However, a few verses later, he extorts the Jewish people: “Ask your father, and he will tell you; your elders, and they will inform you” (Deut. 32:7) as if to confirm the testimony of heavens and earth. Why wasn’t the testimony of heavens and earth enough? Why did their testimony need to be corroborated by “your father” and “your elders”? The Lubavitcher Rebbe The Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, in one of his talks (see R’ Schneerson, M.M. Likute Sihot (Brooklyn, NY: Vaad L’Hafotzas Sichos, 1998) v. XIX, Devorim, pp. 188-196) discusses the Talmudic concept of two types of witnesses: [...]

The Beard of the Long Face is Found

The previous Lubavitcher Rebbe, the Rebbe Rayatz (a.k.a. the Fridriker Rebbe) told the story about his father, the Rebbe Rashab. Once the brother of Rebbe Rashab, Rabbi Menachem Mendel (a.k.a. the RM”M) told him that he read in a magazine an article that stated that scientists found a nerve in the brain regulating the cognitive function so that when a person needed to remember something he would tilt his head looking up, whereas when the person needed to concentrate, he’d tilt his head down. The Rebbe Rashab took his brother to his study, took from the shelf a book by the Second Lubavitcher Rebbe, the Mittler Rebbe, in which it stated the same thing. The Rebbe Rashab said to his brother, “You’d think he was a doctor, but he wasn’t. He saw Adam [...]



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