Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
Moshe Feinstein was a rabbi, teacher, and a foremost modern authority in Jewish law (1895-1986). Feinstein was born in Russia and received his Talmudic education in the yeshivot of Lithuania. He was Rabbi of the town of Luban in Russia from 1921 until 1937, at which date he immigrated to the USA where he served as the head of the Yeshivah Tiferet Yerushalayim in New York.
Rabbi Moshe Feinstein, one of the premiere halakhic
arbiters of his generation, in his office.
Feinstein followed the methods of keen analysis of legal concepts as taught in the yeshivot of Lithuania, with the emphasis on legal theory rather than on its application in practice. He published commentaries in this vein on a number of Talmudic tractates. But Feinstein's fame rests chiefly on his collections of responsa under the name Iggerot Moshe, "Letters of Moses." His decisions in these responsa are widely held to be authoritative for the whole world of Orthodoxy.
Feinstein's general stance is one of strictness in connection with non-Orthodox tendencies in Judaism, even declaring that it is not permitted to answer "amen" to a benediction uttered by a Reform Rabbi. But within Orthodoxy he is very lenient, coming close, for instance, to permitting artificial insemination by a donor, to the consternation of his Orthodox colleagues.
Although the law only permits milk from Gentile farms if a Jew has been present at the milking (lest non-kosher milk be substituted), Feinstein argued that since there are strict rules against the adulteration of milk in the USA and most countries today, it is always a case of a Jew being present. He ruled that an aged, pious man could stay with his irreligious daughter and need have no fear that she will give him non-kosher food to eat. He saw no reason why a blind man should not be allowed to bring his guide-dog into the synagogue during prayers.
Feinstein also discusses theological questions in his responsa; for instance, whether to take out life insurance betokens lack of trust in God. Feinstein declares that, like any other business transaction, insurance is not only allowed but advocated on the principle that human endeavor is required before God's help is forthcoming. Trust in God here means reliance on God to help a man who has taken out insurance to do well enough to be able to pay the premiums.