4209 —תורת היחסות של איינשטיין ומושגים מוחלטים במדע

B"H, 8th of Nissan, 5716.

Brooklyn, NY.

Shalom u'Vrachah!

With thanks, I hereby acknowledge receipt of your books as well as the publications of the Jewish Culture Foundation. There was some delay in their arrival because apparently the package was separated, and my response was also delayed due to many preoccupations.

I was pleasantly surprised to find among your books your work "Einstein's Theory of Relativity," since I did not know you had a hand in mathematics and physics. I was pleased to see on the cover that you did not change your name and it is written as Katz – Kohen Tzedek.

As is my custom in such cases, I append here a few notes at least from what arose for me while perusing your books, even though hastily due to limited time.

Surely by the time you receive my letter, you have already received news from your sister about her return together with her son to Eretz HaKodesh successfully.

As Pesach approaches, I extend my blessing that you celebrate it with your family in kashrus and joy.

With holiday blessings and regards to your brother, M. Schneersohn

All those who explain the theory of relativity naturally emphasize among its conclusions the most surprising ones and place at the forefront: denial of absolute space and denial of absolute time—since both space and time are relative. It is as if this has been proven beyond question—by Michelson’s experiment, then during an eclipse by calculating a star’s path, etc. Consequently, these conclusions are incorporated into scientific assets like Newton’s three famous laws were before their inaccuracies were shown. To my great surprise—in all the books dealing with this theory that I have seen so far—I have not found even one that expresses any reservation about this! And among those studying these books—even more so—no one doubts this assumption!

In my view, not only is a reservation needed here; science in its modern sense—i.e., exact science which draws conclusions only through measurement, weight, etc.—does not possess nor even investigate absolute concepts. The tools of exact science "cannot reach" the absolute. Therefore it cannot deny it (just as it cannot prove its existence).

Furthermore: It is usual that when a scientist completes experiments and formulates their conclusions and laws, he tries—as a hypothesis—to establish a new theory (or introduce corrections to an existing one) in his field whose purpose is to incorporate new findings into scientific assets in that field and explain them more simply or understandably. Even in establishing such a theory—which is only a hypothesis and an attempt to explain part of nature’s phenomena—there is no justification for introducing absolute concepts. Moreover, this contradicts the goal (at least in our case), since doing so makes the description less understandable (if anyone can even grasp what it means): there is no absolute space or time; the speed of light is equal in all directions for all observers; space curves due to matter introduced into it; space (the universe) is limited like a shell and expands or contracts; speed c has a unique property—that it absolutely cannot be exceeded—and so on.

* * *

All scientific experiments conducted—including those regarding relativity—are based on measurement: measuring instruments and the person measuring who summarizes results. Therefore all conclusions reached relate only to measuring space or matter or light, regarding how instruments behave and human abilities. Regarding Fizeau’s experiments, Michelson’s experiments etc.—the most plausible explanation using the fewest outside assumptions should utilize Lorentz’s explanation. The well-known question (also cited in your book) why Lorentz’s phenomenon fits all materials exactly according to changes in speed etc.—a question about measurement by humans—is minor compared to why all nature is limited by speed c—not less nor more. And there is much more to discuss here.

* * *

Regarding your book about Jewish sources on Koren p. xx: Researchers wondered why Gabriel specifically was chosen. It can simply be explained according to Daniel (8 & 9), where Gabriel explains visions and tells what will happen at the end times—see also Daniel 12:6ff (and as known from our sages that "the man clothed in linen" refers to Gabriel). By the way: see Shemot Rabbah ch. 18 sec. 5 where Gabriel was made Israel’s guardian.

About Gabriel and Avraham—see Maaseh Avraham Avinu (in Otzar HaMidrashim).

Pgs XXII–XXIII: The example regarding Rosh Chodesh Elul fast does not fit because Elul comes together with Aseres Yemei Teshuvah—a period of forty days—and its source can be explained by Devarim 22:13 and our sages’ words (Yevamos 48b) "a month of days" as repentance for idolatry etc.

Pg 147: The example from prohibition of marriage with Nethinim seems unsuccessful—they are converts and their prohibition does not relate to idolatry—and it needs clarification why you forced this point when there is an entire section about this in Devarim 7 (and Kiddushin 68b); see also Malachi 2:11–12.

The article appeared in "Cholem VeLochem" p.43.

Summary

The Rebbe highlights that science deals only with measurable phenomena and cannot definitively address or deny absolute concepts like space or time; thus scientists should be cautious before making sweeping philosophical claims based on empirical findings alone.