The HaMaayan exchange was not simply an argument over whether the Murex could produce blue dye. By the mid-1990s, that part of the picture was already fairly clear. Murex snails had supplied the ancient Mediterranean with valuable dyes, their broken shells had been found at dyeing sites, and the same process could be reproduced. The fight was over what all that proves for the mitzvah of Techeiles.
R’ Yaakov Epstein did not dismiss the Murex as ridiculous. He considered it a possibility and permitted someone to wear Murex Techeiles as a middas chassidus. But possible and proven are not the same thing, and he did not believe that the evidence created an obligation to wear it. In fact, he went further: a person who continued wearing white was not necessarily ignoring even a safek mitzvah.
What Counts as an Identification?
Epstein first deals with the rules for identifying an object needed for a mitzvah. He examines mesorah, simanim, umdena and scientific proof, asking how much weight each form of evidence carries in halachah. His concern is that several suggestive simanim do not automatically add up to a definite identification, particularly when the simanim are not unique or can be explained in more than one way.
That standard shapes the rest of his case. Ancient shell heaps prove that Murex dyeing existed, but they do not contain labels saying “Techeiles for tzitzis.” Royal blue and purple are well documented; Epstein does not argue with that. His question is whether those luxury dyes were necessarily the same material that Jews put on a pair of tzitzis. Nor do we possess an ancient strand of tzitzis that can be identified beyond question as Murex-dyed Techeiles.
Epstein also raises difficulties from Chazal and the Rishonim, the exact shade of Techeiles and the reconstructed dyeing process. Some descriptions can be made to fit the Murex, but not always without interpretation. The modern process also produces a dye chemically indistinguishable from plant indigo once the organic material has been removed. He does not say that this invalidates the dye, only that it leaves another part of the reconstruction less certain than its supporters sometimes suggest.
His practical conclusion is cautious but not a ban. Murex Techeiles may be worn as a middas chassidus, provided it is not used to permit shatnez or treated as established Techeiles in other areas of halachah. Publicly adopting it may also raise questions of yuhara for someone whose general conduct is not on that level. Epstein’s point is that love of the mitzvah may justify wearing it, but the evidence has not yet placed that burden on everybody else.
Tavger’s Three Routes to the Murex
R’ Eliyahu Tavger answers that Epstein is demanding a kind of proof which historical identification rarely supplies. More importantly, the Murex case does not rest upon one loose collection of simanim. Tavger lays out three different routes to the same animal: identifying the Chilazon, identifying the ancient dye industry and identifying the terminology used for Techeiles.
His first route begins with the creature itself. Tavger narrows the candidates to a living Mediterranean creature with a shell or casing, a related land form and the ability to produce dye. He also relies on the linguistic meaning of chilazon as a spiral-shelled snail. The ability to make dye is especially important; it is not just another vague siman shared by half the creatures in the sea.
The second route bypasses much of the argument over individual simanim. Techeiles was a famous and extremely valuable product in the ancient world, yet only one ancient industry using a marine creature for such dyes is known from the literature and archaeology: the Murex industry. No comparable remains or written record have been found for some separate Techeiles-producing sea creature. Tavger considers it unreasonable to invent a second, vanished industry when the known one already fits the basic requirements.
His third route is linguistic. The Raavyah quotes a Yerushalmi connecting Techeiles with porphyra, the Greek term associated with the Murex, its dyes and the royal garments colored with them. Tavger adds Rav Binyamin Mussafia and the Chavos Yair, who also identify Techeiles with porphyra. For him, this is not a single clever translation carrying the entire case. It joins two other routes which had already arrived at the Murex independently.
That is why Tavger rejects the conclusion that Murex Techeiles is merely an optional middas chassidus. Any one proof can be questioned if it is kept alone under a microscope. When zoology, the dye industry and the old terminology all land on the same creature, endless theoretical doubts eventually stop being caution and begin emptying the evidence of any practical meaning.
Dr. Daniel Levy: At Minimum, It Is a Real Safek
Dr. Daniel Levy takes a more limited approach. He does not insist that the identification has been established with certainty. His objection is that Epstein sets the bar so high that the Murex does not even qualify as a genuine safek mitzvah.
Levy argues that returning an aveidah or permitting an agunah requires a definite identification because a mistaken decision gives one person’s property or wife to another. Wearing doubtful Techeiles is not automatically comparable, especially if using it creates no corresponding issur. A standard appropriate for an agunah cannot simply be imported here without explaining why.
He also argues that Epstein’s treatment gives the objections more space than the supporting evidence. The ancient world knew only one documented marine-dye industry, and suggesting another unidentified sea creature which left behind neither literature nor factories is difficult. Several reasons Rav Herzog gave for preferring the Janthina also depended on scientific information later shown to be mistaken: Murex dye is durable, Janthina cannot be used successfully for dyeing, and sunlight can turn the Murex solution blue.
Levy’s conclusion is deliberately narrower than Tavger’s. Even if the case is not certain, the evidence for the Murex is at least as strong as the evidence against it. That makes it a safek hashakul and therefore a real safek mitzvah, not merely an interesting possibility that carries no practical weight.
A Later Return to the Same Argument
“Renewing the Mitzvah of Tekhelet — Archaeology or Demagoguery?” is not actually part of the original 1990s HaMaayan exchange. It is a much later anti-Murex polemic, based largely on arguments published in Ohr Yisrael issue 75. It belongs here as a later continuation of the same methodological fight, not as one of the immediate HaMaayan responses.
That article argues that supporters first identified the Murex from archaeology and ancient history, then forced the descriptions in Chazal to fit their conclusion. Its preferred method is the reverse: begin with every siman in Chazal and reject any candidate which fails even one. The sharp title aside, this is the same fault line that had already appeared in HaMaayan—whether the larger historical identification helps us understand the simanim, or whether every siman must first point independently to the animal.
Bottom Line
Epstein, Tavger and Levy were not merely counting how many proofs appeared on each side. They disagreed over the kind of proof halachah requires. Epstein wanted a definite identification before turning Murex Techeiles into an obligation. Tavger believed three separate routes already converged strongly enough to identify the Murex. Levy argued that even if Tavger had not reached certainty, the evidence plainly created a serious safek which could not be brushed aside.
So the issue was not whether lost knowledge can ever be recovered in theory. The real question was what happens when archaeology, language, zoology and Torah sources all point toward the same answer, but no single item closes the case by itself. At what point does continued doubt remain responsible caution, and at what point does it become a way of ensuring that a lost mitzvah can never return?
