I agree that the moon phases is definitely easy to observe. But everyone else in the region seemed to have used a twelve month calendar. A twelve month calendar because one month is repeated every so many years then having a new one added. What starts out as a spring holdiay in a few years becomes a winter holiday. They must have figured out pretty quickly that something strange was going on since months had to be added to keep the holidays in order. Some neolithic cultures had this figured out - a simple observatory like stonehenge will tell you that the sun takes about 365 days to complete a cycle.
And why should a Jew not not use a solar calendar?
The use of a lunar calendar by the ancient Israelites dates back to – well, it depends on when you date biblical authors, but presumably as early as 1200 BC. They weren’t too concerned with counting years in those days, they were concerned with seasons because of the harvest. And the easiest way to track holidays was based on moon – the most ancient holidays almost all occur on the 1st of the moon (new moon) or the 15th of the month (new moon). Remember, they didn’t have printing presses to provide calendars to every home or every village, and the ability to go out and look at the moon and say, “Yep, almost full, holiday be here in a day or so” was the way to standarize observance.
The fact that there were other ancient peoples (the Babylonians, say) on a solar calendar probably indicates that the Israelite calendar pre-dated the Babylonian calendar.
It’s not clear how the seasonal deviation was handled by the ancient Israelites. Probably, the high priests just declared a leap month when they thought the seasons were getting out of tune with the calendar. The codification of an additional month on a fixed pattern (as described above by zevb et al) was introduced before the first century AD as a way of trying to standardize the calendar.
Remember, this was religion and the holidays were divinely ordained based on the moon. “On the first day of the sixth month…” sort of language is found throughout the Old Testament, describing holidays and sacrifices. So, even though they thought the solar calendar was better at tracking seasons and so forth, they couldn’t just discard the lunar calendar. Hence, the fairly complex mathematics of the first century BC to determine a perpetual, regular lunar calendar (so they could follow the traditional holidays) and keep it in sync with the seasons.
It’s interesting that the Muslims, starting their religion much later, absolutely refused to be pay attention to the seasons. I suppose that’s what comes of a religion that starts in a region that doesn’t have a lot of agriculture (namely, Saudi Arabia.)
Actually, the Talmud states that the decision to add a month or not to the calendar(before we had the established calendar we have today) was made on a year-by-year basis by the courts. The decision would usually be made toward the end of winter. The idea was to make sure that Passover came out in the spring (after the equinox). If an extra month was necessary, the month of Adar was “repeated” (and named Adar Sheini [Second Adar]). The decision to add a month could be made any time up until the courts decreed the month of Nissan (which is the month that Passover falls in).
This law actually had some interesting quirks. For example, there is a law that states that if there are two Adars, the second Adar is the “official” one. Thus, a boy born in Adar in a year with one Adar but whose thirteenth birthday comes out in a year with two Adars celebrates his Bar Mitzvah in the Second Adar. Purim is a holiday that comes out on the fourteenth day of Adar. If the courts decided after that point that an extra month was necessary, Purim would be celebrated again!
Likewise, another odd quirk to this law is that you can have a younger child become Bar Mitzvah before an older one. For example, suppose you have two boys born in a leap year – one is born on the 20th day of Adar and the second on the 5th day of Adar Sheini. Now suppose that when their thirteenth birthday comes around, it is a “regular” year. The older boy won’t become Bar Mitzvah until the 20th of Adar, but the younger one will become Bar Mitzvah on the 5th.
The dreidels I use still have nun, gimel, hay and shin. That’s because I’m not there, I’m here, so there.
“Sevivon, sov sov sov, Chanukah hu chag tov; Chag simchah, hu la-am, nes gadol haya sham”
Bachelorette number 2, would you let me cover your latkes with my sour cream? ;j