This past Shabbat in Mekor Rishon, Rav Shabtai Rappaport, who is married to the granddaughter of Rav Moshe Feinstein, published a long retrospective on his relationship with - and undertanding of - perhaps the greatest American posek of the twentieth century. The article traces his history with Rav Moshe, his powerful impressions of this great man, and a critical section on Rav Moshe's understanding of how to issue halachic rulings. I'm assuming that the editors of the paper appreciated the irony in Rabbi Rappaport's claim that Rav Moshe was a halachic conservative, when they named the piece, "The Conservative Revolutionary."
While the full piece in Hebrew is not yet up on the site - I will like to it when it goes up - I took the time to have ChatGPT transcribe and translate the part of the piece that relates to Rav Moshe's halachic rulings. I think it's accurate, but there might be minor errors. Nonetheless, I found the description of Rav Moshe's view on psak both fascinating and critical, due to its understanding of the need for a psak that adapts to changing realities, alongside a steadfast refusal to admit to the innovative and adaptive spirit at the heart of this type of psak.
Rav Moshe’s Methodology in Halachic Ruling
In my view, Rabbi Moshe was a complete halachic conservative—but not conservative in the sense of stagnation. Rather, conservative in the sense of deep-rooted fidelity. He saw himself as a faithful continuator of the halachic tradition across generations and did not believe he had the authority to innovate on the basis of the “spirit of the times.” He wrote many times that we do not have the right, through one pilpul or another, to render our predecessors mistaken, Heaven forbid. What they ruled, they ruled in accordance with the law. It is inconceivable that a generation would declare something untrue, even inadvertently, due to ignorance of reality. Our responsibility is not to correct earlier generations, but to clarify the halacha from the foundations they laid.
From this did not emerge stagnation, but rather a profound dynamism. In Rabbi Moshe’s world, halacha is not an abstract system suspended in midair; it applies to reality—and our perception and understanding of that reality is a living, constantly evolving process. The conception of reality held by earlier generations is not a fixed and immutable doctrine carved in stone, nor does it bind us. When our understanding of reality changes, this does not mean that the Torah changes. Rather, the manner in which we apply it requires renewed clarification. Not because the generation is more modern, but because the knowledge at our disposal has changed. Fidelity to tradition demands fidelity to the reality upon which it operates.
For this reason, Rabbi Moshe often relied on his son-in-law—my father-in-law—Rabbi Prof. Moshe David Tendler z”l, who stood by his side in understanding contemporary scientific perspectives. In this respect he had disagreements with several poskim who sanctified the medical assumptions of earlier generations. Rabbi Moshe was revolutionary precisely out of rooted conservatism, carefully distinguishing between eternal Torah truth and changing scientific conceptions.
So too, for example, in his ruling regarding the determination of the moment of death. In earlier generations, when electrocardiographic monitoring did not exist and precise tools for measuring cardiac activity were unavailable, death was determined based on accepted external signs. We are not permitted to conclude that they erred and buried a living person; they ruled according to the knowledge available to them. However, in a generation that possesses precise medical instruments, if monitoring shows cardiac activity—the person is alive. The halacha has not changed; what has changed is our ability to clarify reality. Indeed, fidelity to tradition obligates us to use the intellectual tools of our time in order to rule correctly.
The same applies in the social sphere. The Talmudic principle “Tav le-meitav tan du mi-le-meitav armelu” (literally: “Better to sit as two than to sit as a widow”), from which various halachic implications were derived, reflects a reality in which a woman saw marriage as an almost absolute value, despite a husband’s flaws. Rabbi Moshe argued simply that in our present reality this assumption is not necessarily correct. A woman in our generation is not prepared to remain married at any cost, and may at times prefer remaining single to living within a harmful or dysfunctional framework. In accordance with this understanding, he ruled that it is possible to annul a marriage retroactively if it constituted a mekach ta’ut—a mistaken transaction—according to contemporary standards. If the underlying social assumption has changed, a posek may not continue building upon a previous premise as though nothing has occurred. This is not the adoption of foreign values nor an ideological revolution; it is a faithful clarification of the reality to which halacha applies. In this matter as well, he stood courageously against those who disagreed with him.
In Rabbi Moshe’s view, reliance on rulings and on the books of earlier decisors is not the essential work of a true posek. Authentic halachic decision-making is a new edifice that the posek constructs through careful study of the Gemara and the words of the Rishonim and Acharonim, and through that process redefines the relevant halachic categories. Such psak makes it possible to rule leniently even where others are stringent—and obligates stringency where others are lenient. However, when a ruling is merely transmitted from books or from other decisors, it does not carry that authority. If it has spread and become accepted practice, one may rely upon it within the boundaries of established custom, but one may not derive new conclusions from it. For that, one must descend to the roots.
For this reason, he opposed the publication of abbreviated halachic summaries extracted from his responsa. For someone who did not ask the original question, the value of the responsum lies not in its practical bottom line but in the detailed analytic process. A posek’s final ruling is addressed to a specific questioner in a specific context; the reader may weigh its reasoning, but bears responsibility for determining whether the ruling applies to his own situation. Out of methodological humility, he saw himself as a teacher offering his students a conceptual framework for their own judgment.
Another clear example of his approach to changing reality is his ruling regarding milk in modern countries. The rabbinic decree concerning chalav akum (“milk of non-Jews”) was enacted to prevent the possibility that non-kosher milk might be mixed in. The traditional definition of such milk is milk that a Jew did not supervise at the time of milking. However, in modern countries there exists a regulatory system overseeing the dairy industry, and there is no practical possibility of mixing in prohibited milk. Rabbi Moshe ruled that such milk is effectively supervised by virtue of its production process and is therefore considered chalav Yisrael. This was not the abrogation of a rabbinic decree nor a flashy leniency, but rather a clarification of the underlying rationale of the decree and its precise scope of application.
