Ask HN: Did lunar calendars cause right-to-left writing systems?

[ykler]

I am not an expert and may be off-base here. But I believe that Chinese and Semitic writing systems are right-to-left (in the Chinese case, up-to-down first) and that these cultures used predominantly lunar calendars. Meanwhile, Western and Mayan writing systems are left-to-right, and these cultures used predominantly solar calendars. The moon waxes from right to left. Is it possible that calendar systems influenced writing direction?

[eesmith]

The Persian calendar is a solar calendar. Persian is a right-to-left language. (Both the older Pahlevi form and the modern Arabic-derived one.)

The Chinese calendar is, technically speaking, a lunisolar calendar. The Hindu and Thai calendars are also lunisolar. Thai is right-to-left.

There does not appear to be a correlation.

[ykler → eesmith]

Obviously most writing systems are derived from older systems, so I tried to only list systems that might have independent origins (although both the Semitic and Western systems come from an area that had writing for a long time, so it is questionable). Old Persian cuneiform was left-to-right (https://en.wikipedia.org/wiki/Old_Persian_cuneiform), while the Pahlavi and modern Persian writing systems have a common origin with Hebrew and Arabic (i.e., Semitic).

Thai (at least today) is left-to-right, but anyway Thai is highly irrelevant since it is derived from Indian writing systems and probably ultimately from Semitic ones (https://en.wikipedia.org/wiki/Brahmi_script).

Old Persian: left-to-right. Calendar: solar. Sumerian: left-to-right. Calendar: lunisolar. Egyptian: left-to-right. Calendar: solar. Chinese: right-to-left. Calendar: lunisolar.

So, anyway, so far the evidence is not strong at all (and I wasn't saying it is), but I'm not yet convinced there was definitely no influence.

[eesmith → ykler]

As you can tell, I didn't research the history that far back. Thanks for the corrections.

Looking now into the history of the Chinese calendar, https://en.wikipedia.org/wiki/History_of_calendars#China says:

> Before the Spring and Autumn period (before 770 BC), the Chinese Calendars were solar calendars. In the so-called five-phase calendar, the year consists of 10 months and a transition, each month being 36 days long, and the transitions 5 or 6 days. During the Warring States period (~475-220 BC), the primitive lunisolar calendars were established under the Zhou Dynasty,

https://en.wikipedia.org/wiki/Chinese_calendar#Earlier_Chine... elaborates:

> Before the Zhou dynasty, the Chinese calendars used a solar calendar.

> According to Ancient Chinese literature, the first version was the five-phases calendar (traditional Chinese: 五行曆; simplified Chinese: 五行历), which came from the tying knots culture. ... The second version is the four-seasons calendar ... The third version is the balanced calendar ..

> In Zhou dynasty, the authority issued the official calendar, which is a primitive lunisolar calendar.

The Shang dynasty came before the Zhou dynasty, and https://en.wikipedia.org/wiki/Oracle_bone_script says that "The vertical columns of text in Chinese writing are traditionally ordered from right to left; this pattern is found on bronze inscriptions from the Shang dynasty onward."

This would seem to mean that the Chinese calendar had a right-to-left writing system and a solar calendar, before switching to a solilunar calendar, yes?

Does that not invalidate your thesis?

In any case, I don't see why there should be any connection. If there are only a few data points, then it's very easy to get coincidental correlations.

What difference does it make?

[ykler → eesmith]

Yeah, if that is right about China, it is pretty damning. And sure, given how few data points there are, it is the kind of thesis that would be impossible to really definitively confirm.