Thread: Baseline representation

Before we can specify indicator encoding, we need to resolve the baseline question. An observation occurs at a moment. But moments are not self-identifying. If I record "three stars visible," how does a reader know which evening I mean?

We need some way to anchor observations. To what, exactly? A Hebrew date provides the day, but not the moment within the day. And even the date requires knowing when one day ends and the next begins—which is precisely what the observation is meant to establish.

I do not have a proposal. I am raising the question so that we may address it systematically.

A Hebrew date provides the day, but not the moment within the day.

Could we not combine the date with a description of the phase? "14 Tishrei, twilight" or "14 Tishrei, night." The phase is what the indicators establish. The date anchors which day.

When does 14 Tishrei begin?

My grandfather's community in Munkács had a simple practice. The shamash would announce the beginning of Shabbat from the steps of the shul. Whatever moment he announced it—that was the moment. If you asked "when did Shabbat begin?", the answer was "when Reb Yossel said so."

This worked because everyone was within earshot. But we are not within earshot of each other. We are building a specification for communities that may never meet.

This worked because everyone was within earshot.

But is this not precisely the problem? We need a reference that does not depend on physical proximity. What can communities in different places independently verify?

Could the indicators themselves serve this purpose? "Three stars visible" is verifiable anywhere with a clear sky. Why should the observation not be its own anchor?

"Three stars visible" is verifiable anywhere with a clear sky.

Three stars become visible in Jerusalem before they become visible in Paris. If I record "three stars visible" in Jerusalem and you record "three stars visible" in Paris on the same evening, these are different moments. How do we express that they are different?

My grandfather told me about the early days of the telephone. People would call between cities and become confused. "I'm calling to wish you good Shabbos"—"But it's not Shabbos yet here"—"It's Shabbos where I am."

Before the telephone, the question did not arise. Each community had its own time. The times did not need to agree because the communities did not speak to each other in the same moment.

The telephone created the problem of simultaneity. Perhaps we are creating it again.

Perhaps we are creating it again.

Are we creating it, or does it already exist? We are attempting to provide a framework for expressing what is already true. The question is whether we can anchor observations in a way that is both locally meaningful and globally comparable.

R. Miriam's point stands: the same indicator in different places refers to different moments. Must we not encode the place as well as the observation?

I have been reading about practices in other domains. Apparently there exist systems of mechanical devices—I believe they are called "clocks"—that divide the day into uniform intervals. Some communities synchronize these devices to a common reference, permitting coordination across distances.

There is even, I am told, an international convention that establishes a single reference point from which all such devices take their measure. If we were to adopt such a convention, would the problem of simultaneity not resolve itself? Could an observation not be anchored to the interval indicated by the synchronized device at the moment of observation?

If the device indicates "18:00," do I know whether it is day or night?

There is even, I am told, an international convention that establishes a single reference point

The deeper problem is the "single reference point." R. Nachmani says there is an international convention. Who established this convention? Where is the reference located?

If the reference is in one place—let us say London, or Paris, or wherever the naval powers decided—have we escaped the problem of locality? Or have we merely accepted someone else's locality as universal?

When I observe three stars in Jerusalem, that observation is grounded in where I stand. If I am required to express it in terms of a reference point in London, am I not translating my experience into a foreign framework? Is the framework neutral, or is it simply powerful enough to present itself as neutral?

Is the framework neutral, or is it simply powerful enough to present itself as neutral?

With respect, did I propose we adopt it because it is neutral? I proposed it because it is common. Does commonality not have practical value? If every community uses a different reference, can we build systems that interoperate?

Do we have two objections to the mechanical reference, or one objection with two faces?

First, R. Miriam's point: does the device reading tell you what you need to know? "18:00" does not indicate whether the sun has set, whether it is safe to travel, whether your children should be home. The number is an abstraction that must be interpreted, and the interpretation depends on where you are and what season it is. Have we escaped the problem, or added a layer of indirection?

Second, the reference point is not neutral. It encodes the decisions of particular institutions in particular places. To adopt it is to accept those decisions as authoritative for our purposes.

But perhaps there is a third path? The observations attested in our sources—three stars, the reddening of the eastern sky, the behavior of animals and markets—are grounded not in any single location but in the lived experience of the observer. They require no external reference. They are verifiable by anyone who can see the sky.

If we anchor our specification in these observations, do we not escape both problems? The indicators are locally meaningful and do not depend on foreign conventions.

They require no external reference.

They require the Talmud.

I don't follow.