Established, But Not Sanctified

The Hook

The first sentence of this chapter undoes a great deal of work. The Rambam has spent seventeen chapters building an apparatus that can tell a court, in advance and to the minute, where the moon will stand and whether its crescent can be seen from Jerusalem tonight. He opens chapter eighteen by saying that it is well known and obvious that even when the calculations indicate the moon should be sighted, the sighting is only probable.

Cloud, he says. Or the place where the watchers stood happens to be a valley. Or a tall mountain in the west is blocking them, and then it is as though they were standing in a valley whether they are or not. The instrument is exact and the world is not. What follows from that admission is the strangest ruling in these laws: a court that can compute the month is not permitted to sanctify one.

Clouds, Valleys, and a Mountain in the West

Before anything else the Rambam wants the judges to understand what visibility depends on. A man standing in a low place will not see the moon even when the crescent is large. A man on a high and lofty mountain will see it even when the crescent is very small, and so will a man living on the seashore, and so will a man travelling on a ship in the Mediterranean. Then the seasons. On a clear day in the rainy season the air is clean and the heavens look more brilliant, and the moon shows larger. In the summer the air is like smoke because of the dust, and the same moon looks small.

Now put those two facts together with the numbers. When the arc of sighting and the first longitude are both near their minimum, the crescent will be small and it can be seen only from a great height. When they run long, and degrees have been added past the minimum, the moon appears large and the visibility grows with them. So the court is instructed to keep its attention on two things whenever testimony arrives: the season in which the moon was sighted, and the place where the witnesses were standing. And the Rambam tells the judges to ask that second question out loud. Where were you when you saw the moon.

He works an example. The arc of sighting was nine degrees and five minutes, the first longitude exactly thirteen degrees, both of them barely over the line, and witnesses arrive claiming they saw it. If this happened in the summer, or if the men were standing somewhere low, the court suspects their testimony and subjects them to a great deal of cross examination. If it happened in the rainy season, or in a very high place, then the moon would surely have been sighted unless clouds hid it, and the same testimony sits differently in the room. The identical numbers, the identical claim, and what decides how hard the court presses is the weather and the ground under the witnesses' feet.

The Month You May Establish and May Not Sanctify

Then the problem the chapter exists to solve. Witnesses saw the moon at the proper time, the court sanctified the month, twenty nine days were counted, and on the night of the thirtieth the moon was not seen, either because it could not be seen or because cloud covered it. The court waited out the whole thirtieth day and nobody came, so a day was added and Rosh Chodesh fell on the thirty first. Now it happens again in the second month. And if you say a day should simply be added each time, the Rambam follows the arithmetic to its end: month after month of thirty days, until in the last month of the year the moon would be visible on the night of the twenty fifth or the twenty sixth. There could be no more ludicrous and demeaning situation than this, he writes, and he refuses to treat it as a rare accident. It is very likely, he says, and it happens often in countries with long rainy seasons and cloudy skies.

The remedy is a tradition transmitted from one to another back to Moses. When the moon is not sighted at the beginning of the months, month after month, the court establishes one full month of thirty days and one lacking month of twenty nine, and it calculates its way forward alternating them, and sometimes two full or two lacking in succession as the numbers require. Then comes the clause that ought to be read slowly. They establish these months, and they do not sanctify them. For the sanctification of the months is dependent solely on the sighting of the moon.

Everything downstream follows from that separation. The calculation is aimed at keeping the moon sightable next month at its proper time and not before, never on the night of the twenty eighth. Never fewer than four full months in a year and never more than eight. A month made full by calculation still gets its celebratory feast. The passages in the Talmud where the court appears to rely on computation, and the year in which Rabbi declared nine months lacking, all belong to this same principle and to the same condition, which is that the moon was not seen at its proper time. And when the moon is seen at its proper time, its first shining after conjunction with the sun, it is always sanctified. Always. The arithmetic never overrules an eye.

West, East, and the Only Place That Counts

The chapter closes with geography, and the geography is asymmetrical in a way that catches most readers. If the moon is sighted in Eretz Yisrael, it will be sighted in every land to the west at the same latitude. But if the calculations say it will not be seen in Eretz Yisrael, it may still be seen in those western lands. Therefore, the Rambam concludes, a sighting in a country west of Eretz Yisrael tells you nothing about whether the moon was sighted in Eretz Yisrael. Only the failure carries information westward: if the moon was not sighted on the mountains of those western countries, it certainly was not sighted here.

Turn east and the arrow reverses. If the moon was not seen in Eretz Yisrael, it certainly was not seen in the eastern lands at the same latitude. If it was seen here, the east is uncertain. And so a sighting reported from a country to the east proves that the moon was surely sighted in Eretz Yisrael, while a failure reported from the east proves nothing at all, and it may well have been seen here. Two riders arrive with the same word on the same night, one from the west and one from the east, and one of them has told the court something and the other has not.

And all of it is bounded. These statements hold only where the countries lie at the same latitude as Eretz Yisrael, thirty to thirty five degrees north; further up or further down and the parallels break and the reasoning does not carry. Then the last line, which reframes the entire discussion after the fact. The Rambam says he laid all this out to clarify the laws of sighting and to make the Torah great and glorious, and not because people living east or west should depend on what they themselves can see. Their sighting is of no consequence whatsoever. We rely only on the sanctification performed by the court in Eretz Yisrael.

The Unifying Principle

What holds this chapter together is a distinction between knowing something and being authorized to say it. The court can know, with an accuracy that still impresses astronomers, that the crescent is there tonight. Knowing does not sanctify. Sanctifying requires two men who were standing somewhere, in some weather, who looked up. The Rambam does not treat this as a limitation on the science. He treats it as the definition of what a month is.

The Alter Rebbe teaches that the moon has no light of its own, that everything it shows is received and returned, and that this is why Israel is compared to it. A body that generates nothing and reflects everything is the correct emblem for a people whose calendar depends not on what is true but on what has been witnessed and accepted. And the Rebbe drew out again and again what the verse means when God hands the months over with the word hachodesh hazeh lachem, this month is yours. The power to sanctify was given away. Once it is given, the Owner of the moon does not overrule the court that received it, and the court does not overrule the two men on the ridge.

The Baal Shem Tov taught that nothing a person encounters is accidental and that the place where he happens to be standing is part of what he was sent to do. Chapter eighteen makes that literal and puts it in a courtroom. Where were you when you saw the moon. Not as small talk and not as suspicion, but because the answer changes whether the testimony can be believed, and the testimony changes whether the month exists. And the Sfat Emet, reading the smallness of the moon at the start of every month, finds there the pattern of a beginning that always looks too slight to build on. The court in this chapter has to act on exactly that: a sliver, at the edge of the possible, seen by two men in the wrong season from the wrong altitude.

Modern Application

Most of the arguments people carry around are about the numbers. We are certain we know how the thing looks from where we stand, and we assume everyone at the same latitude is seeing the same crescent. The Rambam takes that assumption apart with two sentences of geography. A report from the west proves nothing here, though it feels like proof. A report from the east proves a great deal, though it comes from further away. Both riders are honest and only one of them is evidence, and the difference is a structural fact about where the light falls, not about anyone's character.

The other transferable ruling is the one about establishing without sanctifying. There are stretches when nothing can be seen, and the honest response is not to keep adding a day and pretending the sighting is still coming. It is to fix the sequence by the best calculation available, keep the structure intact, hold the feast, and be scrupulously clear with yourself that this is an established month and not a sanctified one. The Rambam builds that distinction into the calendar so that no one confuses the two, and so that when the moon finally does appear at its proper time, it is sanctified immediately and without argument.

The Closing

Elul is the month when this chapter reads least like astronomy. A person doing an accounting at the beginning of Elul is in the position of the court in a long rainy season. There has been no clear sighting for some time. The instinct is to keep extending, to add another day and wait for the moment of certainty that will make everything legible.

The Rambam's ruling is that you may not extend indefinitely, and you may not manufacture the certainty either. Establish the month. Keep the count honest, make the feast, do not call it sanctified. And keep asking the only question the court is instructed to ask out loud, which is not what the calculation says, but where exactly you were standing when you thought you saw the light.