Q. What prayer value does Rabbi Yishma’el’s list of logical principles passage (at the beginning of the morning service) have?
A. Rabbi Yishma’el’s list of thirteen principles of Biblical interpretation – from the beginning of the Midrashic work known as the Sifra – is actually not original, but that is not the point. The problem, if there is one, is what the passage is doing in a prayer book.
One possibility is that everything we do during the day should accord with two doctrines – that we should think and decide everything logically, and that every moment of the day we should be conscious of our Torah heritage as expounded by the sages.
Another view is that as Rabbi Yishma’el was a kohen, reading a passage ascribed to him reminds us of the Temple ritual which is now in abeyance.
More prosaically, some say that it is not the content of the passage as such which is important but the fact that mourners follow it by saying the first Kaddish of the day.