Follow ChabadInfo & Never Miss an Update!

Follow us on Instagram Subscribe to our WhatsApp status and broadcast Follow us on Tiktok Follow us on Facebook Follow us on X Follow us on Google News Subscribe on YouTube

By Rabbi Shlomo Ezagui 

I may sometimes be quoting complicated rules of Jewish law, and the subject of quantum mechanics isn’t simple. Still, if you stick along for the journey, you will come away more knowledgeable in both fields (a brilliant thing), and, you will discover new ideas that will inspire and strengthen you in your own life.

This article will help you appreciate that not only in science, but long before that, in our Holy Torah, your decisions today can have a real positive impact on past choices, and what your children do in the future can truly affect what you are doing, today.

Modern-day science is helping us understand and better relate to Torah concepts in a physical scientific way. Modern-day science allows us to appreciate the statement of our sages, “Torah is the blueprint to the Universe.” All the wonderful rules and concepts in our Torah, for thousands of years, are all finally being discovered in the principles of modern-day science.

Let’s start with some background. On Shabbat or Yom Tov, a person may not walk more than 2,000 amot – cubits (about 4,000 feet) beyond their place of residence, which is measured from the edge of the city. However, Jewish law provides a mechanism called eruv techumin. By placing food before Shabbat at a new location, you can make that spot your new “home base,” and the 2,000 amot – cubits are measured from there instead of your actual home.

The Rambam (Mishneh Torah, Eruvin 8:3) explains that it’s even permissible to set up two eruvin in opposite directions. You can make a stipulation: “If there’s a mitzvah (it’s only through this power of the Mitzvah) or necessity that arises tomorrow and requires me to go in this direction, then I rely on this eruv, and the other is of no consequence. If I need to go the other way, then I rely on the eruv in that direction. If I need to go both directions, I can choose whichever eruv I want. And if I don’t need either, then I’m like everyone else in my city and can walk 2,000 amot – cubits  from the city’s wall.”

This means you don’t have to decide conclusively in advance which direction you’ll go. Your actual need on Shabbat determines (retroactively – that’s the key word) which eruv is “active,” as if that was your intention to begin with.

The Maggid Mishneh explains that this halacha depends on the concept of breira—retroactive clarification. For rabbinic laws like eruv, breira means that it’s considered, retroactively, as if you had the intent from the start, to use the eruv in the direction you eventually needed.

Normally, a person must set up their eruv before nightfall, and doing it on Shabbat is invalid, but since you made a stipulation beforehand, we rely on breira and say that it’s “as if” you decided before Shabbat began.

The key is in the power of the pre-Shabbat stipulation. You must declare before Shabbat: “If I need to go east, my eruv is east; if west, it’s west; if both, I choose whichever I need.” This creates a framework for breira.

The eruv’s validity is determined retroactively, by what happens on Shabbat. For example, if you need to flee danger to the east, the western eruv is retroactively void, and vice versa.

The Rambam (based on the Mishnah and Talmud) explicitly permits this, provided the stipulation was made before Shabbat. The eruvin aren’t being activated in real time, but are validated, after the fact, based on your pre-Shabbat stipulation. This keeps you within the rules of eruv techumim, while allowing for unpredictable needs (see Talmud Eruvin 36b–37a and Tosfot).

The stipulation of Breira allows one to not only retroactively change the designation of one Eruv but also on one Shabbat switch from one eruv to the other based on one’s needs! This might seem strange—how can a person in the present have any influence on the past? Time moves forward, so how can the present affect the past, or the future affect today?

People have long wondered if the future can influence the past, not just the other way around. We just saw that it can!!  This concept is explored not just in Jewish law but also in modern science.

In quantum physics, there is a similar concept called retrocausality. This means that what happens in the future can sometimes influence what happened in the past. Retrocausality provides a coherent framework for quantum phenomena, emphasizing that cause and effect may not be strictly linear at the microscopic scale.   For example, in some experiments, a tiny particle, such as a photon, appears to “choose” how it acted earlier based on a measurement made later. If you put a detector in place, the photon acts one way; if you don’t, it acts another way. Your later choice seems to reach back and determine what the photon did before.

Both Jewish law and physics allow for this kind of “looking backward,” even when they impose limits to prevent things from getting out of control. In Jewish law, you must establish your conditions before Shabbat begins; in physics, although the future can influence the past in certain ways, you can’t use this to send messages back in time or create time travel issues.

There are even deeper connections. In Judaism, the mitzvah of teshuvah (repentance) enables a person, through genuine regret, to transform past actions for the better.

These ideas encourage us to think differently about choice and fate. Jewish law states that you have free will, but your choices align with God’s plan. Some scientists suggest that both the past and future help shape the present. In both the Torah and science, we see that time is more flexible than we typically believe. The past isn’t always fixed, and the future isn’t merely waiting to unfold. Instead, they are interconnected, and our actions now can impact both directions.

By weaving together ancient law and cutting-edge physics, these concepts reveal a timeless truth: the past isn’t set in stone, and the future isn’t just a blank page. Instead, they’re partners in a cosmic dialogue, each shaping the other in ways that are both profound and practical. And that’s a powerful takeaway:

Our choices, when made with intention and preparation, through the guidance and will of God Almighty have the power to shape not just your future, but even your past. Both Torah and science remind us that reality is more flexible—and more hopeful—than it seems.

In His infinite mercy, God grants us the extraordinary ability, through His permission and will, to revisit and elevate our past, allowing us through that change and improvement to build a stronger and more meaningful foundation for our present and future. What we are setting in place today, in many ways, will be defined by the choices made in the future.

www.rabbishlomoezagui.com

9