📋 Shiur Overview
Summary of the Shiur – Laws of Kiddush HaChodesh Chapter 11
Introduction and Foundation of Chapter 11
Chapter 11 is the beginning of the astronomical calculations in the Laws of Kiddush HaChodesh. The learning begins with the foundation that “Torah is only acquired by one who kills himself over it” — the pain of admitting that one doesn’t yet know is itself part of kinyan haTorah (acquiring Torah).
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Review of the Foundation from Chapter 6 and Chapter 7 — Two Types of Kiddush HaChodesh
The Rambam says “lefi she’amarnu behalachot elu” — he is referring to Chapter 6 where he said “she’bizman hazeh mechashvin bedikduk veyod’im im yera’eh hayare’ach o lo yera’eh”.
Explanation:
The Rambam establishes two periods with two halachot:
1. Bizman sheyesh beit din be’Eretz Yisrael (Sanhedrin) — they sanctify based on sighting. Witnesses come, we learn Masechet Rosh Hashanah, we provide provisions for the witnesses, we sanctify according to what they saw.
2. Bizman she’ein beit din — they sanctify based on calculation, a tradition from Moshe Rabbeinu. This is the calculation of molad hamemutzah (average molad) that the Rambam explained in previous chapters.
Insights and Explanations:
a) The Calculation of Ibur is Only an Approximate Calculation — Rosh Chodesh Can Be “Twice Off”
Our Rosh Chodesh is “twice off” from the actual sighting:
1. Molad hamemutzah vs. molad ha’amiti: The molad that is announced in shul is the molad hamemutzah (29 days, 12 hours, 793 parts for each month), but in truth the months are not always the same length — in winter or summer they are slightly longer or shorter. The average works out very well over a long period (perhaps off by only a few seconds), but for an individual month it can be off.
2. Molad vs. sighting: The molad (zman hakibbutz — when the sun and moon stand in the same place) is not the same as when one can see the moon. At the molad itself one cannot see anything — it takes at least six hours or more until the moon moves far enough from the sun that one can begin to see it. Additionally, there are practical factors like clouds.
3. Chadashim male’im vachaseirim: A month is 29½ days, but Rosh Chodesh cannot be half a day. Therefore we make one month male (30) and one month chaser (29), which leads to another deviation from the true molad or sighting.
The Rambam himself says that Rosh Chodesh can be even two days off from the true molad.
b) Chochmat Ha’ibur vs. Chochmat Astronomia — A Fundamental Distinction
An important distinction:
– Chochmat ha’ibur = the approximate calculation of molad hamemutzah, which is used to make the calendar (Rosh Chodesh, chadashim male’im/chaseirim).
– Chochmat astronomia (= cheshbon tekufot hamazalot) = a precise wisdom that tells us when the moon itself actually is, to the second. This is theoretically one hundred percent accurate.
[Digression: The Pli’ta’s teaching that Hashem made the moon so that people could measure, and the verse “se’u marom eineichem” — the Rambam’s foundation that the beginning of knowledge of God is to look at the heavens.]
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Halacha 1 — The Beit Din of Sighting Had to Know Astronomy
The Rambam says that “beit din mechashvin bedikduk veyod’im im yera’eh yare’ach im lo yera’eh” — the Beit Din that sanctifies based on sighting had to know the true astronomical calculation.
Explanation:
The Beit Din had to be able to calculate precisely whether the moon would be visible or not, in order to be able to judge whether the witnesses are credible.
Insights and Explanations:
a) The Great Chiddush: The Opposite of What One Would Think
One would have thought: in the time of sighting one doesn’t need any calculation — you look outside and you see. In our time one specifically needs a calculation. The Rambam says the opposite: today we go with an approximate calculation (molad hamemutzah). But the Beit Din of sighting had to know the true precise astronomical calculation — in order to be able to judge whether the witnesses are credible.
b) Why Does the Beit Din Need to Know Astronomy? — Examination of Witnesses
Testimony is only accepted on a davar efshari (possible matter), not on a davar bilti efshari (impossible matter). If the Beit Din knows through astronomy that it is impossible to see the moon today, then even if witnesses come — they are false witnesses. The calculation tells when it can be, and when it cannot be.
c) Testimony of the Moon vs. Other Testimony:
With other types of testimony we don’t ask whether what the witness says is “possible” according to natural laws. But with testimony of the month, because it can seem that one sees the moon when one doesn’t actually see it, the Beit Din must know astronomy in order to confirm whether what the witness says is at all possible.
d) Not Only False Witnesses, But Mistakes:
The concern is not only that witnesses will deliberately give false testimony, but also that they will make a mistake — it is very easy for a person to look at the sky and think he sees the moon. Especially when it is cloudy or a difficult day.
e) The Principle That Testimony Must Be Within the Realm of Possibility:
If witnesses come saying something that is a niman (impossible), we don’t believe them — even if they are kosher witnesses. If according to the calculation the moon cannot be visible today, and witnesses come saying they saw it — we don’t believe them, because “miracles” don’t happen with the moon according to the Rambam.
[Digression: The Chacham Tzvi (not Chavot Yair) regarding miracles and testimony — he said that when witnesses come saying a miracle happened (like a chicken without a heart), we believe them, because it is against nature but not impossible. But according to the Rambam, with the moon there are no miracles — the natural laws are fixed.]
f) The Question on the Rambam: If the Beit Din Already Knows Precisely, Why Do We Need Sighting at All?
This is a well-known question. The answer is “not enough” (not fully satisfying as a reason), but the halacha is certain — we need sighting even when we already know the calculation. The Beit Din sits, learns astronomy, knows that today the moon can come — and yet we must wait for witnesses. Even when it is cloudy and one practically cannot see it, we do not make Rosh Chodesh based solely on calculation (bizman shemekadshin al pi re’iya). In the middle of the day we become aware that it is Rosh Chodesh — this creates practical confusion for people, but essentially the calculation of Rosh Chodesh is always from the night before.
g) Another Question: It is “a bit mad” that only because of the situation of examining witnesses should one have to learn entire astronomy. The Rambam must mean that it is more than just a practical reason — it is a wisdom that has value in itself.
[Note: A Ramban is mentioned who said something like “always the thirtieth day was already the molad” — but the exact language is not certain.]
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Halacha 2 — “Lefi Shema’ati… Shebeit Din Mechashvin Bedikduk… Yit’orer Leida Otam Haderachim”
The Rambam’s words: “Lefi shema’ati behalachot elu shebeit din mechashvin bedikduk veyod’im im yera’eh yare’ach im lo yera’eh… yeda’nu shekol mi sherucho nechona velibo ta’ev ledivrei chochmot… yit’orer leida otam haderachim shemechashvin bahem ad sheyeda adam yera’eh aruva.”
Explanation:
Because we have heard that the Beit Din calculates precisely, every person with a proper soul will acquire a desire to know the calculation himself — until he will be able to calculate himself whether today the moon will come.
Insights and Explanations:
a) “Yera’eh” — What Does This Word Mean?
A question: does “yera’eh” mean that the moon exists (has already been born), or that one can see it (no clouds)? The conclusion: “Yera’eh” is already “next level” — when it is relevant that one can see it, it has already “been born.”
b) The Rambam’s Motivation for Learning Astronomy — Not Only for Practical Purposes
The Rambam doesn’t say that one must learn astronomy in order to make kiddush hachodesh. He says that the wisdom itself is important — “divrei chochmot” and “sodot.” A person with a “rucho nechona” will naturally acquire a desire to know the calculation. This is connected to what the Rambam says in Hilchot Yesodei HaTorah regarding knowledge of the greatness of the Creator through astronomy.
c) “Rucho Nechona” — A Sharp Expression
“Rucho nechona” doesn’t mean just a wise person, but a person with proper character traits, an “adam nachon,” a normal person. “Libo ta’ev” is already weaker — that is the desire. But “rucho nechona” is a good character trait, a precondition: if you are a proper person, you will naturally want to know.
d) “Sodot” — What Does the Rambam Mean?
What is the “secret” in astronomical calculations? No clear answer is given, but the point is: when there is a wisdom and a secret, a normal person acquires a natural desire to know it. If the sages had not revealed the calculations, this would have been a secret — and the sage would have emerged every month from his cave and said “Ko amar Hashem, the moon comes at exactly such and such a time” — and people would have served him. This shows how great the wisdom is.
e) Yitron HaDa’at Al HaChushim — The Intellect is Higher Than Seeing
The main chiddush: the expression “ad sheyir’u” doesn’t mean only that one should be able to confirm the calculation through seeing, but the opposite — the intellect can see things more clearly than the eyes. The eyes can be clouded, but a proper calculation is always precise. This is yitron hada’at al hachushim — the intellect is superior to the sense of sight.
f) The Parable of a Ba’al Ruach HaKodesh
Imagine a prophet comes out and says he knows devarim nistarim venifla’im — he can say every month precisely which day, which minute, and from which side of the world one should look to see the moon. People would have been crazy for such a person — they would have said “Hashem Himself speaks with you!” But this is exactly what chochmat hatekufot gives — the same ability to predict, but through calculation instead of through prophecy. The sage is almost like a prophet.
g) Why People Underestimate Wisdom Compared to Prophecy
People think that when Hashem says something it is impressive, but when a person makes a calculation it is “just a calculation.” But in truth the sage who can predict to the minute when something will happen — this is truly from the virtues of man. This is compared to chatzot halailah — Moshe Rabbeinu said “kachatzot” (approximately midnight) because the itztagninim (astrologers) of Pharaoh could not precisely determine midnight, and if they could have, they could have said precisely.
h) The Smile of the Sage
When does the greatest pleasure come? When the moon comes out exactly when the sage calculated — “See, I was right!” — that is the smile. But the main virtue is not the confirmation, but the knowledge itself beforehand — that the sage knows a secret that no one can see with eyes.
[Digression: Aristotle’s Metaphysics and the Rambam — the Rambam’s assumption is based on Aristotle’s famous opening: “Kol bnei adam sho’afim lada’at” (“All men naturally desire knowledge”). The proof of this is that people love their senses (especially sight/seeing) not only for practical purposes, but for the essential pleasure of knowing. Why is the sense of sight especially important? Because sight is “mavchin” (distinguishes) the most distinctions — one sees colors, shapes, very many details. Hearing, smelling, other senses are much less mavchin. (~90% of information comes through sight.) Sight is also the most clear — even when one hears an orchestra, only when one sees it does one get the full clarity. The distinction between sight and intellect: The virtue of eyes is that one doesn’t need to exert oneself — it is easy for everyone. But with deeper wisdoms that require mental work, laziness or weakness enters. But one who doesn’t have these problems (“rucho nechona”), just as one wants to see, he wants to understand. People want to know — but whether they want to pay for it (work through it), that is another question.]
[Digression: Greatness of the Creator through astronomy — the Rambam’s approach in Hilchot Yesodei HaTorah that through learning astronomy one comes to knowledge of the greatness of the Creator and the lowliness of man (“bri’ah shefala va’afela neged Tzur tamim de’ot”). A brief discussion about the moon’s size — it is a third of the earth, but in comparison to the entire system it is small, which gives perspective on the greatness of creation.]
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Continuation of Halacha 2 — “Vedarchei Hacheshbon… Chachmei HaGoyim HaKadmonim”
The Rambam’s words: “Vedarchei hacheshbon shechakru chachmei hagoyim hakadmonim al cheshbon hatekufot vehagimtriot… yesh bahen machlokot gedolot… veha’anashim chachamim gedolim nishtabshu bahem… veta’alem lahem devarim venoda lahem sfeikot… veyesh mi shedikdek harbe velo faga baderech hanechona becheshbon re’iyat hayare’ach ela tzalal bemayim adirim veheela cheres beyado.”
Explanation:
The Rambam relates that among the ancient sages of the nations there were great disputes regarding the calculations, great sages struggled, and some exerted themselves greatly but did not achieve the correct calculation.
Insights and Explanations:
a) “Chachmei HaGoyim” — Why Only Gentiles?
The Rambam says here “chachmei hagoyim” without mentioning Jews, whereas earlier (regarding length of years) he said “chachmei Yisrael vechachmei umot ha’olam.” Perhaps the Rambam wants to hint that Jews knew the correct calculation, and only among gentiles was there the great dispute.
b) “Gimtria” — What Does It Mean Here?
“Gimtriot” means here geometry (chochmat hamidida), which is needed for astronomical calculations. Or perhaps “gimtria” is a general name for mathematics in general, as it was once called. The Rambam himself explains that gimtria = chochmat hamidida. The Gemara’s language “tekufot vegimtriot” (or “pirparot lechochma” in another place) is also mentioned.
c) “Nishtabshu Bahem” — What Does This Mean?
Not only that they struggled between disputes, but in general — when there is a dispute, it means that somewhere clear knowledge is lacking, and one (or both) is wrong.
d) “Tzalal Bemayim Adirim Veheela Cheres Beyado” — The Parable of Diving in Deep Waters
The Rambam uses the language of Rabbi Akiva in Bava Kama (regarding the laws of guardians): “Tzalalti bemayim adirim veheliti cheres beyadi.”
– Mayim = chochma: The Rambam brings in Moreh Nevuchim that sages call Torah “mayim” — water is an image for wisdom.
– Yam = deep secrets: The sea has beneath it entire worlds — on top it looks like black water, but when one dives in, one sees colorful worlds. This means that one must dive in to the wisdom to find the secrets.
– The parable of two learners: One studies a smaller wisdom but brings it out well. The second dives in deep waters — a strong, deep wisdom — but brings up only a cheres (shard). He exerted himself tremendously, but did not achieve the true calculation of re’iyat hayare’ach.
e) “Ulefi Orech HaYamim Verov Bedika VaChakira” — The Long Path to Truth
The Rambam relates that after much time and many generations of investigation, some of the sages finally achieved the correct calculation. There were many people with the proper spirit to want to know, and there was a whole enterprise devoted to it — but it took many generations until they gradually achieved it.
📝 Full Transcript
Laws of Sanctifying the New Month Chapter 11 — The Wisdom of Astronomy and the Difference Between Molad HaMemutzah and Molad HaAmiti
Introduction — Humility and Lowliness in Learning the Calculations
We are now going to learn Laws of Sanctifying the New Month Chapter 11, where the calculations begin. And since we don’t understand the calculations, we’re going to use this as an opportunity to have a bit of humility (shfilus), a bit of lowliness (anavah). Which is actually appropriate for the Three Weeks, the Nine Days one needs to be broken. What is the whole joy of resolving doubts (hatarat hasfekot)? It seems that there is sadness in resolving doubts, and one doesn’t understand, and somehow one feels fearfully broken. Let’s learn what it says here, see what the Rambam says.
Okay, “Since we said in these laws”… This is a problem with people who don’t learn, they don’t have any humility in learning, they want to know everything. “Adam ki yamut ba’ohel, the Torah is only acquired by one who kills himself over it.” The pain of acquiring knowledge, of admitting that I don’t know it yet. Okay.
Chapter 11 — The Rambam’s Introduction to the Astronomical Calculations
In short, practically speaking, Chapter 11, the holy Rambam says, “Since we said in these laws”, as he says, he points out that in Chapter 6 he said, “that in this time they calculate precisely and know whether the moon will be seen or will not be seen”. Right, very important.
This is, how does the Rambam’s understanding come about here? This is what I know to say about this.
Review — Two Laws According to the Times: Sanctification by Sighting and Sanctification by Calculation
That is to say, seemingly, we saw in Chapter 7, and people might think that when they sanctified based on sighting they didn’t need to know any astronomy. We saw in Chapter 7 approximately like this, there was once, there are two laws throughout the times, as the Rambam lays it out.
In the time when there is a Beit Din in the Land of Israel, a Sanhedrin, one must sanctify based on sighting. One waits for witnesses to come, one learns Tractate Rosh Hashanah, one makes provisions for the witnesses, it happens, one sanctifies based on witnesses who saw the new moon.
In the time when there is no Beit Din, the Rambam says, there was also a tradition from Moshe Rabbeinu, that one sanctifies based on calculation. This is the calculation of the molad hamemutzah (average conjunction) that the Rambam taught us in whatever chapter he did.
The Calculation of Molad HaMemutzah — An Approximate Calculation
The Imprecision of the Calculation
It’s not a precise calculation. That calculation is an approximate calculation, it’s easy to calculate, it’s off by a few hours, somewhere there’s a difference. It’s more or less. It’s not just a few hours, it can be that one is off by a whole day. Not every single one, it’s between all of them.
No, the Rambam says that it can be that even Rosh Chodesh should be two days removed from the correct time, from the molad ha’amiti (true conjunction). In any case, it’s an approximate calculation. That is to say, it can be either removed from the molad ha’emtza’i (average conjunction) and also from the molad ha’amiti. Rosh Chodesh.
Discussion — How Much Can Rosh Chodesh Be Off?
Okay, in any case, yes, remember? That’s how it comes out. Okay, no difference.
Yes, you see, when one calculates… It can be that one Rosh Chodesh it should happen, or each one is moved a bit. Yes, it can also happen that everything should be two days.
The Reasons Why the Calculation Is Only Average
There are various reasons why, one, part of the reasons why the calculation is only average is because the months are longer in the winter or in the summer, I don’t remember which. It’s not always, not a whole year is the month the same length. By hours.
Molad HaMemutzah vs. Molad HaAmiti — The Reality in the Synagogue
And one announces the molad, the molad that is called out in the synagogue is the molad ha’emtza’i, not the molad ha’amiti. And you see clearly that it doesn’t come out many times, it can be two days before Rosh Chodesh, two days before Rosh Chodesh, two days before Rosh Chodesh, not always the same time.
In any case, the law is that one goes with this calculation, and according to this calculation one also makes Rosh Chodesh two days and one day, according to the calculation that we learned, the calculation of intercalation (cheshbon ha’ibur). There is a calculation of how much, because there are 29 and a half days, so it works out, one must make it exact. Anyway, this is all a calculation.
Discussion — What Does “Off” Mean? Off From What?
But I want to understand, when you say it’s off, do you mean to say it’s off from when we can see that it comes up in the sky, or it’s off from the calculation?
According to the calculation it’s off. Both, both the calculation is off. It’s twice off. Our Rosh Chodesh is twice off.
Let’s understand why. If I’m not right, you’ll tell me. It looks like it’s twice off.
Our Rosh Chodesh Is “Twice Off” — Three Reasons
First — Molad HaMemutzah Is Not Molad HaAmiti
First of all, the molad that is called out, we have a molad that is called out when it’s Rosh Chodesh. The molad that is called out is the molad ha’emtza’i. That is to say, let’s say the average of twelve months, 12 times 29 days, 12 hours, 793 chalakim that we calculate the molad equal every month, is not truly equal every month. The months are a bit more or a bit less, I don’t know which, perhaps we’ll find out soon.
So naturally they calculate that the molad is only an average molad. Practically speaking, the calculation is quite precise, if I remember, with reality it matches quite well. Perhaps it’s off by a few seconds literally, the 12 days, 29 hours, 793 chalakim of the month. Okay, that’s one thing.
Second — Molad Is Not Sighting
Second, the molad has nothing to do with Rosh Chodesh. The molad, seeing the moon, they’re going to learn this now. Seeing the moon one can only a day or two after the molad.
It depends whether the molad is during the day or at night, because the molad is the time of conjunction (zman hakibbutz), it’s the time when the sun and the moon are in the same place. So then one can’t see anything, it takes at least six hours, or more.
Discussion — The Difference Between Sighting and Molad
The sighting is also carried. The sighting goes with the sighting and with the molad two different things. Sighting is after the molad. Sighting has to do with clouds, with things that don’t have to do with the essence of the molad. Even before the clouds, soon there are the clouds.
First it’s during the conjunction, the definition of the time of molad is when one doesn’t see the moon. When the moon is stuck, it’s completely opposite the sun that one can’t see it at all. It needs to move a bit so one can begin to see it. Now it depends if it’s at night. Just so it takes a bit until one sees it, no? How long the light travels.
From the sun it takes a few minutes, but from the moon it doesn’t take much time. The moon is very close. Because it’s simply there, it’s ten opposite, one can see it then. So that’s one thing.
Okay, but the molad can calculate when one will see the moon. The molad must essentially be before Rosh Chodesh always. So that’s one reason why the molad is… So two things.
Third — Full and Deficient Months (Chadashim Malei’im VaChaserim)
Discussion — Can the Molad Be in the Middle of Rosh Chodesh?
Many times the molad is on the day of Rosh Chodesh. Can it be before the day? As if… One minute, wait, wait.
Let’s say like this, the calculation called molad is not the same calculation as the sighting, number one. Number two, it’s a molad hamemutzah. It’s not the correct molad. The months are not always exactly so. Okay.
Second, our Rosh Chodesh can’t be at the time of sighting or at the time of molad. Why not? Because a month is twenty-nine and a half days, and the moon is twenty-nine and a half days, and Rosh Chodesh can’t be half a day. Therefore one makes one month full and one month deficient, approximately, according to various calculations, so it should come out more or less not too far.
But according to this it comes out that sometimes it’s removed by another day from the molad or from the sighting, okay? It’s interesting, so that it shouldn’t become removed too much on the large scale, and one will further on the specific day precision, as if. There is no specific day precision, as if always…
I remember the Ramban had some sharp word about this, he said something once that always the thirtieth day was already the molad ascent, but something like that, let’s be precise that it’s correct, one saw one erred whether it’s right.
The Wisdom of Intercalation vs. The Wisdom of Astronomy — A Fundamental Difference
In any case, yes, okay. Now, okay, what this is a calculation, okay? A calculation that tells us when Rosh Chodesh is. So one would think that calculation is the opposite of sighting. In the time of sighting one goes, one looks out, sighting, and one doesn’t show in with calculation.
The Ramban comes, one says, no. I’ll tell you something new: the whole calculation is a fake calculation, it’s only an average calculation. And the calculation doesn’t tell us when one will see the moon at all, it tells us at all when the molad is. A completely different thing.
Now, but you should know that there is a true calculation. A true calculation is called astronomy. The wisdom of astronomy is not the same as the wisdom of intercalation. The wisdom of intercalation is an approximate calculation. The wisdom of astronomy is when the moon… it’s like a practical wisdom.
Discussion — What Is the Wisdom of Intercalation?
How? What makes the calendar?
The wisdom of making a calendar. Making a calendar, making the calculation.
Yes, yes, but it’s called about making the calendar.
The Wisdom of Astronomy — The Precise Calculation of the Moon Itself
But there is besides this a wisdom that tells us when was the moon itself, not the calendar. The moon itself also has some wisdom, and this is a calculation called, as it came in, Sod’vei, Overever, the calculation of the cycles of the constellations (tekufat hamazalot). This tells us when the moon itself, this is a precise calculation. To the second of course, one can make mistakes, and perhaps they don’t know precisely, but theoretically, the wisdom is astronomy precisely one hundred percent. It’s also a math, right? It’s also calculating…
Digression — The Almighty Made the Moon So People Could Measure
Now, certainly, the holy Plita said that the Almighty wanted us to be able to measure, so He made the moon. So it also says in the verse, “He made the moon for appointed times, the sun knows its setting.” Not measure, but yes, the planets, this teaches us to measure.
Now, for this it’s very important what one learned, that the beginning of wisdom is to look at the moon, and begin to see that there is a calculation in the world, there is a complication. The Rambam says that the beginning of knowledge of God is to look at the… a part, a verse. Well, Isaiah the prophet said that one must Torah from Shabbat Nachamu. Anyways, I want to say about this here.
The Great Innovation — The Beit Din of Sighting Had to Know the True Astronomical Calculation
When Is the Astronomical Calculation Relevant?
Therefore, now, when does one make this calculation? The calculation is a… the astronomy, when is it relevant. The Rambam comes and says, listen, do you know when it’s relevant? Sanctifying based on sighting. But then the Beit Din will determine when they will accept testimony.
Very good. Exactly.
The Beit Din Must Know Whether the Testimony Is False Testimony
Ah, one goes in the testimony goes, it’s fine, I want also, but the Beit Din can see. Whether the testimony is false testimony. And to refute them. They need to know the true calculation, one can’t go with an average molad, the molad has nothing to do with the witnesses, the witnesses see the reality, they don’t see the calculation of the ascent.
One can’t say that the calculation is when the moon can be, and the witnesses come say when they actually saw it. The calculation is when it can be, when it can’t be it doesn’t concern me that the witnesses come. Not only does it not concern me, even if they come they are false witnesses. Because they are establishing that a witness is only on a possible thing, not on an impossible thing.
The Rambam’s Great Interesting Thing — Opposite of What One Would Think
The Rambam says a great interesting thing, that essentially the Beit Din of sighting had to know the true calculation. We don’t need to know it, we go by sighting. Exactly opposite of what we would think, that today one needs less because one does calculation by average, whereas the Beit Din didn’t need to have any average calculation, because once one goes with witnesses, first of all, yes there is such a thing as half a day Rosh Chodesh.
Discussion — Half Day Rosh Chodesh
No, there’s no such thing as half a day Rosh Chodesh, I don’t hold there is.
Not half a day Rosh Chodesh, but that one becomes aware in the middle of Rosh Chodesh that today is Rosh Chodesh.
Yes, yes, yes, but that’s not the… there’s still gonna be full and deficient months.
That’s not the point. It will come out perhaps a bit different, I don’t know how it worked, that’s the truth. One must ask how it works, I need to think about this. But the Rambam says yes that in the middle of the day one became aware that it’s Rosh Chodesh, and he says what one does with this.
Yes, yes, that’s true. Regarding Rosh Hashanah it’s much more problematic. It becomes problematic, practically people get confused, but essentially the calculation of Rosh Chodesh is always from the night before, that’s no difference. When one only becomes aware in the middle of the day, what happens with this that one must make thirty? It seems it works itself out.
The Question on the Rambam — Why Does One Need Sighting at All?
In any case, there’s a question that people always ask on the Rambam, according to the Rambam, why does one need the sighting at all? If the Beit Din knows precisely when one will, and the answer is not enough. This is the law certainly. Why? The reason for the law is perhaps sharp, but the law is certain according to the Rambam that one must first the Beit Din sit and learn astronomy and know that the moon can come today.
He doesn’t say that it can be cloudy, one can’t always make it, even if it could, and the like. Or there are sometimes other situations that make it practical, and one shouldn’t be able to see it.
Yes, so this is therefore, the holy Rambam says, according to the tradition in these laws,
Continuation: Why Does One Need Testimony on Rosh Chodesh According to the Rambam?
Speaker 1: I don’t know how it worked, that’s the truth. One must ask how it works, I need to think about this. But the Rambam says yes, it’s very clear that in the middle of the day one became aware that it’s Rosh Chodesh, and he says what one does with this.
Yes, yes, that’s true, but it doesn’t make it much more problematic. It becomes problematic, practically people get confused. But essentially, the calculation of Rosh Chodesh is always from the night before, that’s no difference. One only becomes aware in the middle of the day. What happens with this that one must perhaps make thirty?
In any case, there’s a question that people always ask on the Rambam, according to the Rambam, why does one need the sighting? One needs the sighting at all. If the Beit Din knows precisely when one will, the answer is not enough. This is the law certainly.
Why? The reason for the law is perhaps sharp, but the law is certain according to the Rambam, that one must first the Beit Din sit and learn astronomy and know that the moon can come today. Also this, because it can be cloudy, one can’t always make it, even if it could, and the like. Or there are sometimes other situations that make it practical, one shouldn’t be able to see it.
Yes, so this is therefore, the holy Rambam says, according to the tradition, they said, these laws.
The Matter of Examining the Witnesses – Why Must the Beit Din Be Expert in Astronomy?
There’s a special thing, because you’re now making that the judges must be a whole tremendous thing. Why? Because you’re sanctifying the month. It can be that witnesses many times it seems difficult to be, see in the Gemara that it can seem…
But Rebbe, why is it so important? The Rambam, it feels like you found an excuse why the Beit Din can be tremendous. But I don’t know.
One doesn’t say about other types of witnesses. I mean, other types of testimony is usual. One comes to say that person was desecrating Shabbat, I mean to say before this that it can be, that that person, the Beit Din doesn’t say, that person is the type of person that it can be relevant to say about him such a thing. I have two kosher witnesses around saying, they say. Ah, every person is a type of person who can’t be, but if there are things that are not possible, if it’s a thing that can’t be, even kosher ones it can’t be.
I don’t mean, let’s say, perhaps one does need to know. It can certainly be that there are many things. Preconditions for the witnesses to come, that the witnesses are within the realm of things that are relevant. It’s certain that the Rambam will say so, if one knows that something is impossible, witnesses come and say, okay, of course.
Digression: The Chacham Tzvi About Miracles and Testimony
You get the problem with miracles (nissim), and the Chavos Yair that you remember, the Chavos Yair said that if witnesses come to testify about such a miracle, we believe their miracle, because it goes against nature (teva). But regarding the chicken without a heart, however, Chacham Tzvi, not the Chavos Yair, Chacham Tzvi doesn’t.
But in any case, according to the Rambam certainly, he will say that you see in a miracle and the moon didn’t come, there are no miracles with the moon. If witnesses come, and seemingly according to this it’s the same logic of testimony (edus).
I think there are certainly sources in the Rambam that say this, we need to find them. Seemingly also that it’s not necessarily that we’re afraid of false witnesses (edei sheker), but rather we’re more afraid of mistakes. It’s very easy for a person to look at the sky and think… especially when we need more important witnesses, that’s actually when it’s cloudy or a difficult day, which someone caught.
A Question: Why Must One Learn All of Astronomy Just for This Situation?
But it’s a little weird to see that just because of this situation one should need to learn all of astronomy. Now we need to include knowing the greatness of the Creator (gdolos haBoreh), and the lowliness of man (shiflos ha’adam), as he says in Hilchos Yesodei HaTorah.
So the Rambam said, regarding shiflos ha’adam he didn’t say. Oh yes, “beriah shfeilah va’afelah” (lowly and dark creature), “neged tzur tamim deyos” (against the perfect Rock of knowledge), I don’t know, the great Creator.
True, but when the moon looks at the moon, we throw at the moon. Isn’t the moon so small?
Perhaps yes, according to the Rambam yes, because the moon doesn’t… no, but the moon gives further perspective, that the moon is so much smaller than you will see, and yet it is so much greater than us. It’s further the… okay, in any case, it’s not greater than our moon.
If a person goes up to the moon, where will he become, it’s huge. A person can’t walk around the whole moon, it will take weeks, it’s still big, a third of the world. A third of the world is big. Okay. But it can’t give perspective on the greatness of the system (hamaarechet).
The Principle That Testimony Must Be Within the Realm of Possibility
Let’s just understand something else. I think in other laws of testimony (hilchos edus) the law will also be this way. If someone comes and says, I saw someone jump twenty-four feet high. The beis din won’t believe it, it can be testimony. Testimony isn’t a matter of the Almighty’s. Someone will when it can be. They do it like this, yes.
We certainly need to say some language of the Rama, it says this clearly, I don’t know regarding what. We’ll certainly find it. Okay, let’s continue.
Halacha 2 – The Rambam’s Motivation for Learning Astronomy
The Words of the Rambam
Speaker 1: “Lfi shema’ati behalachos elu shebeis din mechashvin bedikduk veyodim im yeira’eh yarei’ach im lo yeira’eh.”
Lfi shema’ati asher ani parshas, lfi shema’ati, already, so we don’t know this. Lfi shema’ati behalachos elu shebeis din, lfi shema’ati behalachos elu shebeis din, they calculate precisely (mechashvin bedikduk). It doesn’t mean approximately. Veyodim im yeira’eh yarei’ach im lo yeira’eh (and they know if the moon will be seen or will not be seen).
What Does “Yeira’eh” Mean?
The interesting thing is, I don’t know if the word is yeira’eh, because yeira’eh means whether there are clouds, whether the moon can be there, whether the moon isn’t there. Clouds also, the clouds mean it’s not there, on this come some of the others, there where there aren’t clouds.
No, but I’m saying yeira’eh isn’t because it’s there, yeira’eh is already the next level. When it’s relevant, when there is a yeira’eh, the yeira’eh has already been born.
The Desire to Know – The Rambam’s Assumption About Human Nature
“Yeda’anu shekol mi sherucho nachon velibo ta’ev ledivrei chachmos velamad al hasodos, yis’orer lada’as osam haderachim shemechashvin bahem. Ad sheyeda, im yeira’eh aruvah.”
He heard a great stretch. The beis din needs to know for a practical reason. It can’t be that he now needs to learn all of astronomy for such a crazy thing, so that the beis din, this isn’t… first read what he says.
What does he say? Shekol yisrucho nachon (that everyone whose spirit is proper). You heard that there is a calculation when we can, when we can, when we can, precisely when the moon is. That’s what he means to say. Therefore, the moment he heard this, certainly, you’re a good person, immediately comes a great longing (hishtokekus) to know the calculation.
The Rambam goes with this that when we see that it’s relevant, we see that a great person (adam gadol) can do it, we must get a desire (ta’avah), I want to be able to do it too. You see that there are some people who can do it, there is the beis din who can do it. There is such wisdom (chochmah), yes.
Discussion: What Does “Yeda’anu” Mean?
Speaker 2: I think so. Yoda’ani is an interesting expression. Yoda’ani means he about himself I know, or he means that we all need to make a calculation from this that it’s possible to know. Therefore, yoda’ani, we know.
Speaker 1: Ah, what do you mean? Who is yoda’ani?
Speaker 2: He means presumably every person should take from this a lesson that we know that it’s possible, therefore that it’s possible.
Discussion: This Is Based on Aristotle’s Approach
Speaker 1: This is based on Aristotle. Aristotle said that everyone wants to know all wisdoms. Remember? So? Everything that one can know?
Speaker 2: Yes.
Speaker 1: Nu, remember? Do you remember the beginning of the Metaphysics?
But this is here, because the Rambam doesn’t say because of all wisdoms. He says that this wisdom is very special. He doesn’t mean we need to know it in order to make kiddush hachodesh (sanctification of the new month), right?
Speaker 2: Right, right, right.
Speaker 1: He says, this wisdom is an important wisdom. I don’t know if he said that because this is important, he doesn’t mean that. It means the opposite. What he means to say is not that we need to know it for practical purposes (letzoreich maaseh) in order to know when it’s Rosh Chodesh. He means, what is there a wisdom and a secret (sod) that everyone wants to know? If there is such a wisdom, immediately you want… and a secret.
Speaker 2: There’s a wisdom, if you have a secret, you want to know. What is there, he on the secret?
Speaker 1: I don’t know what he actually means by the word sod.
Speaker 2: Good question.
Speaker 1: And here you have the… nu, I don’t have an answer.
Discussion: What Does “Rucho Nachon” Mean?
I want to tell you something, “rucho nachon” means that otherwise you’re not a proper person. “Libo ta’ev” is already weaker, is already someone whose libo ta’ev. “Rucho nachon” is simple, if you’re an adam nachon, if you’re a normal person. It’s a sharp expression.
Speaker 2: Yes, yes, it’s a good quality. “Rucho nachon” means that one has proper character traits (midos), right? Ruach is something a topic of midos, the desire for knowledge (teshukos hadaas), the awakening (his’orerus).
Speaker 1: He says “da’ato muchanah,” but seemingly he’s not right. “Rucho nachon velibo ta’ev ledivrei chochmah.” No, he means something like a good person.
Aristotle’s Metaphysics – “All men naturally desire knowledge”
Look what it says: “All men naturally desire knowledge.” A great greatness. He brings this though from a different version. All people naturally have a desire, kol bnei adam, I don’t know the language he said. Sho’afim lada’as (aspire to know).
Speaker 2: Yes, sho’afim lada’as, and they have proof of this.
Speaker 1: Look, “An indication of this is our esteem for the senses.” Did you know that all people love what they can see? Their senses, their senses. “For apart from their use, we esteem them for their own sake.” We have pleasure from what we can see, not just because through this we can travel somewhere. You have pleasure from seeing beautiful things, from seeing things.
And especially from seeing, not just “for the view to action.” He said that it’s not the knowledge, it’s the pleasure, but he says that it’s the knowledge. You want to know, and you want to see because you want to know more. He says that seeing is… and even when we love to see things, even when we aren’t in order to do something about it.
Why Is the Sense of Sight Particularly Important?
Why? Because seeing helps us the most… why does a person most value the sense of sight? There are other senses, a person can’t smell, not dangerous. The sense of sight people tremendously value.
He says, why? Because seeing, this also has to do with the moon, it’s all sight, sight. That is, from seeing one can see the most distinctions. The eyes give you the most information. I once read that something like ninety percent of the information that a person receives comes from his sense of sight.
Why? Simply because seeing distinguishes the most distinctions. Right? You see colors, you see shapes, you see very many things. Hearing, you can hear two, three distinctions: how high it is, what the sound is, how low it is. You don’t hear very many things. The other senses distinguish much less. Sight distinguishes the most.
This is the most intellect (seichel), the seichel means to understand distinctions, this is so, this is different. Sight is also the most clear. That is, even when a person hears a whole orchestra, but when he sees that it’s an orchestra, he will see the full… this is clarity. This is what he calls distinction, the distinctions, distinctions, right?
In short, already. And therefore they love the most order. In short, a story, if we had the senses simply to survive, so that we could know where the bread is to be able to eat. He says that it’s not so. He says that we look much more than we need to. People love the very act of looking, the very act of knowing. It’s built in that a person has a desire for knowing. So he argues in any case. This is the simple assumption of Aristotle.
Discussion: The Advantage of Eyes Is That One Doesn’t Need to Exert Effort
Speaker 2: It’s very interesting, but the eyes, the advantage of the eyes is that you don’t need to exert yourself, therefore it’s easy for everyone. But truly you would want… night, I say, other kinds of knowledge that you can’t see with the eyes, but when you need to use the mind, there comes in laziness or weakness. But someone who doesn’t have these problems, just as one wants to see, he wants to understand.
Speaker 1: Yes?
Speaker 2: He says, a person will want, whether they want to pay money for it, work through it. That’s still a question, but want they will want.
Speaker 1: Yes, already.
The Rambam’s Application: The Desire to Know Astronomy
So, therefore the same thing will be. You hear that there is a calculation, this is the best thing, you can know precisely when the moon will come? Any normal person gets a great desire to know this.
To such an extent, you will know the calculation so well, not “ad sheyeda” with the goal, you will know so well until you will be able to calculate whether today the moon will come. It’s such a tremendous greatness, a normal person needs to look with his eyes to see the moon. When you will just have a calculation, you will know for certain whether the moon comes.
I think that “ad sheyeda ra’uy” is that he wants to know that it’s astronomy until…
Continuation: The Advantage of Knowledge Over the Senses – The Intellect Is Higher Than Seeing
Speaker 1: You hear that there is a calculation? Ah, the best thing, you can know precisely when the moon will come. Any normal person gets a great desire to know this. To such an extent, you will know the calculation so well, not “ad sheyeda’u” is the goal, you will know so well until you will be able to calculate whether today the moon will come. It’s such a tremendous greatness.
A normal person needs to look with his eyes to see the moon. When you will just have a calculation, you will know for certain whether the moon comes.
I think that “ad sheyir’u” is like he wants to know that they have astronomy, not just that the moon needs to come out. This is the advantage of knowledge over the senses (yisron hadaas al hachushim). The sense can’t say precisely. The sense can’t say that not knowing on top, but knowing with clarity.
Yes, yes, I said that, but I’m telling you just that very… this is something that we cry with the eyes that we couldn’t see. We can know according to what we knew from next month, that when two months you will know, today the moon comes.
And there’s also something else, it’s a way how you prove his knowledge if his knowledge is good. Because a person would have made astronomical calculations, and he can’t prove it by seeing the moon.
I don’t mean the proof, I mean the advantage that the intellect can see things that the eyes can’t see, or he can even see clearer than the eyes. You said before that we can’t see the Almighty, it’s a weak problem. It’s clearer. You will test it, you will see that it’s correct, but it’s clearer than the eyes. Sometimes the eyes will be clouded, sometimes the eyes will never be clouded. If the calculation is correct it’s always so.
The Parable of a Person with Divine Inspiration (Ruach HaKodesh)
Speaker 1: And it’s ruach hakodesh, you want to know a secret. You say the word sod? Imagine, imagine what if a prophet comes and he says, speak with the people so that further wise men will understand what I speak.
Imagine what if a prophet comes, a person with ruach hakodesh, and he says, rabbosai, I am a person with ruach hakodesh, I know hidden and wondrous things (devarim nistarim venifla’im). What do you know? Come here. You know that every month the moon comes, people struggle, they travel to the mountains to know when the moon is. I will tell you every month precisely which day, which minute, and which side of the world, precisely where to look there how to see the moon. Wow! The Almighty Himself must speak with you, I don’t want to.
Discussion: The Excitement of Calculation – Proof or Advantage?
Speaker 2: But I think perhaps to say that it’s a bit different, the “ad sheyir’u.”
Speaker 1: No, no, because it’s not a bad interpretation. I’m saying that the excitement is that every month you can prove that you indeed had the good calculation. Because when a person can make calculations, it seems to him very beautiful calculations, but it won’t be proven.
Listen, listen, you think exactly the opposite. You know what you think exactly the opposite? You think exactly the opposite of what the truth is. What we’re saying here is that seeing, that thinking, knowing is better than seeing. Not that we need to arrive from this.
Speaker 2: But a thought that we can prove is much stronger.
Speaker 1: No, it’s not, it’s not. The thought I prove. Because he will see every month in the land, it’s not. “Tzaddik tzaddik atah” (You are righteous) all the time important, like today’s heretics (apikorsim), who think that eyes are better than intellect. No.
Certainly, the way that we find out the calculation that we begin with is from looking. But what I’m telling you, that’s why I said my whole parable with the person with ruach hakodesh.
Why are people so impressed with a person with ruach hakodesh who knows everything? Because he knows things that we can’t see. You need to see, certainly you won’t say that the person with ruach hakodesh’s advantage is that we can check him, certainly you won’t check, he has nonsense, it’s not the point, he needs to know that he has nonsense.
But the advantage is that you don’t have any way with your eyes, you don’t know which side to search, when will the moon come, after you’ve seen you can know that you’ve seen, but before you can’t know. He knows a secret, he as it were, if for example, in other words, let’s say for example, if they hadn’t told us the secrets, the calculations, it was a secret.
The wise men come, he comes out from his chamber there, his cave every month, and he says, rabbosai, ko amar Hashem (thus says God), the moon will come exactly such a time. Every month he’s right precisely to the second, we will look, we will serve this person, true?
And this is what wisdom gives, this is what the wisdom of the constellations (chochmas hamazalos) gives, that you can know every month precisely.
Speaker 2: But you say, the person who knows, when will he know?
Speaker 1: I’m saying that the person will smile. When will he smile? When the moon will come out, exactly then when he calculated. See, I was right.
Why do you read it backwards? Why don’t you look backwards? I’m starting to hear what I’m saying, because I’m telling you much better what you’re saying, because I know what I’m talking about.
No, I want to show you why this is amazing, and people think, for some funny reasons, people have been thinking that if it would say the Almighty told me, ah, if it’s a prophet, I made a calculation, ah, just made a calculation.
I’m telling you better, you’re already saying no prophet who can predict to the minute when something will happen. Like midnight (chatzos halailah). Moshe couldn’t say, because their astronomers didn’t know precisely that they didn’t have good astronomers, and if they had good astronomers, they could have said precisely. When you turn midnight, yes? It’s amazing.
It’s not strange that I say that all human beings strive for this. You see that people would go crazy for someone who knows such a thing, right? You understand? It’s very normal. We have forgotten that this is a wisdom that one can predict.
Certainly you’re right that if he just says calculations that don’t prove themselves to be so, it’s worth nothing. I’m saying, but he’s going to say beforehand, I can say this now until the end of all generations when the moon will come. I am a prophet like me, right?
But also in your wisdom, not something like that, you know small things, you are connected with the great world, with the enormous heavens. Certainly, this is also yours, the heavens are a great thing, the heavens are such a kind of thing that one can only even, it has in it such wisdom, not everything.
In this world, most things, it’s harder to know than this. But this is one thing that one can know with an astounding punctuality. It’s a tremendous thing, it’s truly from the virtues of man, from the… he is truly a god, he cannot be. In Columbus, whatever, yes?
Let’s download it. Okay, I hope it’s good, I have no strength.
You understand it this way, therefore this is the boldest, you understand why boldest? There is a Jew who doesn’t need to look at the moon to know when it will be. Certainly, you will look at the moon to know when it will be. Certainly, you will look to check that you were right. He doesn’t need to. He looks in his book, it’s a magic calculation, he knows when the moon will be. Imagine that. Tremendous. It’s truly a…
Why don’t people understand this? Why don’t more people want to learn astronomy? What happened to us? And they’re not just one after another, they’re somewhat mixed up with us. Okay, let’s go further.
And the Methods of Calculation – The Disputes Among the Ancient Gentile Sages
Speaker 1: In the methods of calculation, already, now. And the methods of calculation, he says, there are great disputes… It’s an awakening why one should learn. Yes, and the methods of calculation, the methods of calculation that he says, what is the calculation of the calculation of the calculation of the calculation of the ancient gentiles who investigated the calculation of the seasons and geometries. Interesting.
Discussion: What Does “Gematria” Mean Here?
Speaker 2: Gematria, relationship.
Speaker 1: He throws in the word gentiles. It means that they weren’t Jews, because earlier he said gentiles and Jews, did he mention something somewhere?
Speaker 2: Yes, in the chapter when he spoke about the length of years of life, he said the sages of Israel and the sages of the nations of the world were divided on it. Here he says, the gentile sages.
Speaker 1: Ah, perhaps he wants to go say that the Jews were able to… Let’s finish. There was a great dispute. Who investigated the calculation of the seasons and geometry. The relationship of gematria I don’t know.
Speaker 2: Gematria, as you say, perhaps he means geometry, but what does it come in here? One needs to know geometry something to calculate on the heavens?
Speaker 1: Let’s say what the Rav means by this. Could be. Okay. Okay. He says the science of measurement. He puts geometry, the science of measurement.
Speaker 2: Geometry means… I know what geometry is, but what is the… Just because it’s such a kind of calculation about this. Okay.
Speaker 1: Perhaps gematria he means to say as a name for mathematics?
Speaker 2: Could be, it could be once upon a time one used to call it generally like this.
Speaker 1: The Gemara says, yes, what does the Gemara say? Tekufot and gematriot? No? Isn’t that the language of the Gemara? The question is what he means. Tekufot and parparaot chochma it says in one place. In any case, okay.
Great Sages Struggled
Speaker 1: And great wise men erred in them. What does erred in them mean?
Speaker 2: Among the disputes, because there are disputes one could struggle.
Speaker 1: No, no, no, in general, there are disputes. Dispute means that somewhere there was lacking clear knowledge. There is one who is wrong. Through both are wrong.
And things were hidden from them, and doubts became known to them. Interesting, he uses there several linguistic devices.
And there is one who was meticulous four in the letter dalet and did not hit upon the correct path in the calculation of the sighting of the moon, but rather dove in mighty waters. Why does he use such an interesting language? Dove in mighty waters, and what do you think he brought up after that? The other leviathan he brought up, poor thing.
Discussion: The Language “Dove in Mighty Waters”
Speaker 2: That’s the language? It’s a language of a Gemara?
Speaker 1: I don’t know, but it’s a metaphor that is a… I remember that the metaphor but… dove, influence and in Bava Kamma.
Speaker 2: Ah, he brings, no? And in Bava Kamma tzedeket kesef, Rabbi Akiva said I dove in mighty waters and brought up pottery in my hand. He says this about the thing? Let’s see about what he says it.
Speaker 1: No, there’s a difference, it’s a sugya there in Bava Kamma. Not the point. The point is, what does he call there “depths upon mighty waters”?
Speaker 2: Nothing, about laws of guardians, righteous. It’s not the point. The word is something else.
Speaker 1: The word is, this goes with the image that the Rambam brings it in the Moreh in a place, I remember, that the sages call Torah water. Water is an image of wisdom, and there is also the image that one swims in it.
I mean to say the sea, not water, but sea specifically, because under the sea there are still whole secrets that you can only know when you go deep in, right?
Speaker 2: I don’t know how it connects. There are two, there is water and there is “this is the great and wide sea, there creep innumerable things”. Two things. There is drinking that one drinks, it quenches the mind, just as there is drinking, there is another thing that you say such a sea, there is a sea of wisdom, like sea of wisdom, sea of Talmud, no matter how deep one swims, one becomes aware of whole worlds.
Speaker 1: Because the water on top looks like it’s some black water. You go in, you see whole colorful worlds. One must also dive, one must dive into the water. And he is a great diver, and he brings up a portion. Interesting such a thing.
Speaker 2: No, you can think of it like two people go to study. One studies a stupid wisdom, but the stupid wisdom he got out tremendously well. The second one went and did a lot, a strong thing, dove in mighty waters, but you don’t have what to show for it.
Speaker 1: Yes, that’s the image. Very good.
And According to the Length of Days – After Much Time One Achieved
Speaker 1: And according to the length of days… already, but… And according to the length of days… later it took a lot of time. And through much investigation and inquiry. It looks here like there were many people who had the correct spirit indeed to want to know, and there was the whole system for it. It became known to some of the sages the methods of this calculation. He says a simple thing, that this is indeed a thing that one must look at the sayings, one must hold one’s head a lot, after much time, gradually one didn’t become accustomed. There were enough generations to…