Mathematics and Judaism Come Together

Recently, we completed the counting of the Omer and observed the holiday of Shavuot. Counting seven weeks of seven days, or 49 days, brought to mind other things that are counted in Judaism.  There are other time periods – the three weeks between the 17th of Tammuz and Tisha B’Av, and the first nine days of Av leading up to that notable date. The 40 days of Elul, which include the 10 days of penitence. We count the four Shabbatot leading up to Passover. We count the Shabbat itself every seven days. If you are on a desert island and lose track of time, you can determine when to observe Shabbat by counting seven days and recognizing each seventh day as Shabbat. We count the years, every seventh year being a Sabbatical year and the 50th year being a Jubilee year. We count the commandments in the Torah , coming up with 613 – according to our Sages, 365 negative commandments (equaling the days of the year) and 248 positive commandments (equaling the bones in the body).

Hebrew in particular lends itself to numerology, since its letters are also used as numbers. Thus, the value of various words is calculated and they are compared with one another in the case where two words have the same total. This is part of the basis of Jewish mysticism.

The Jewish people themselves are not to be counted. Rashi and other commentators explain that this is possibly because you can cause a plague to fall upon those whom you have counted. Or, following Hosea, it could be because the Children of Israel are as numerous as the sands of the sea and cannot be counted. Counting is often achieved by a one-to-one correspondence – for instance, the Biblical census consisted of collecting half a shekel from each person. The amount collected tells the number of people in the count. Or, in counting for a minyan (the ten people required as a minimum to say certain prayers), sometimes a verse with a known number of words is recited, one word for each person. Or they are just counted “not-one, not-two, not-three”, etc.

As a person whose degrees are in mathematics (I’ve had a long and varied life!), I am always entranced by reading mathematical excursions in the Talmud – I’ve seen algebra and geometry in there, as well as a great deal of simple arithmetic. Numbers were so vitally alive in ancient times. I think of Pythagoras and how his school attributed specific qualities to various classes of numbers. Number Theory was one of my favorite classes in graduate school. So to have it completely intertwined with Judaism is a delight to my soul.