The spectacle of the universe becomes so much the grander, so much more beautiful, the worthier of its Author, when one knows that a small number of laws, most wisely established, suffice for all movements. Pierre Louis Maupertuis (1744) Among the more or less general laws, the discovery of which characterize the development of physical science during the last century, the principle of Least Action is at present certainly one which, by its form and comprehensiveness, may be said to have approached most closely to the ideal aim of theoretical inquiry. Its significance, properly understood, extends, not only to mechanical processes, but also to thermal and electrodynamic problems. In all the branches of science to which it applies, it gives, not only an explanation of certain characteristics of phenomena at present encountered, but [...]
The least action principle is an expression of teleological reasoning where the initial states of the system are determined by the endpoints—the beginning and the end.
The Talmud (tr. Shabbat) discusses two opinions about the manner in which we are to light Chanukah menorah. According to Hillel, we light the first light on the first night, two lights on the second night, etc. increasing the number of lights every night. According to Shammai, we are to do the opposite – light eight lights on the first night, seven on the second night, and so on diminishing the number of lights every night (according to how many days of Chanukah are still left). The Talmud concludes, ele v’elie diveri Elokim chaim (this and that are words of the living G‑d, i.e., both opinions are true and reflect the will of G‑d), but the Halachah (the practical law) is according to Hillel. The Arizal explains that whereas the law today is [...]
There is hardly a Jewish holiday more widely celebrated than Passover (Pesach). Jews of all denominations, affiliations, and levels of religious observance, if any at all, gather at the Passover Seder to tell the story of the Exodus from Egypt. What is often lost amid all of the beautiful rituals, not least among them the singing of Had Gadia and other Seder songs, is the deep meaning of this holiday, which is far more profound than a mere recollection of historical events, no matter how important they may be. What is, then, the deeper meaning of the Passover that transcends its historical significance? On the morrow of Shabbat One obscure and little-known (outside of the observant Jewish community) commandment ("mitzvah") may lead us to a deeper understanding of the meaning of the Passover—this [...]