Techeiles - Is a Specific Chilazon Required?

In the last post, I discussed the potential of rediscovering the חלזון התכלת in this day and age. For one who accepts the argument of R' Soloveitchik, the debate is entirely academic, and even if you could ascertain what the חלזון is, there would be no practical application, and you would continue to wear only white strings on your ציצית. If you accept the alternative approach, which rejected the Radziner תכלת only because of a negative-מסורה, then there is a potential practical application, should you find a חלזון that has no problem of a negative-מסורה. With respect to the Murex Trunculus, which is commonly used today as the source of תכלת, we can ask two questions:

1. Is the Murex Trunculus the חלזון that was used in the times of Chazal to produce תכלת?
2. In the event it is not the actual species that was used, is it kosher to be used to produce תכלת? In other words, when the תורה says that תכלת must come from a חלזון, is that referring to a specific חלזון, or could you use any species that classifies as a חלזון, assuming there exists such a species?

Let us begin by examining a Tosefta in the ninth chapter of Menachos:

"תכלת אין כשרה אלא מן החלזון, הביא שלא מן החלזון פסולה"

"Techeiles is not kosher unless it is from the Chilazon. If one brought [techeiles] which is not from the Chilazon it is invalid". 

The Tosefta is very particular in stating both the conditional and its converse. Not only do we stress that תכלת from a חלזון is valid, we stress that if it comes from a different creature it is invalid.

Now, let us explore our options. Either there exists only one creature named "חלזון" in the universe, or it is a generic name, and there may be two or more types of חלזון. Suppose for a moment that exist two or more חלזונות in the world. In that case, they are certainly both valid for תכלת, for if one was valid and the other invalid, the Tosefta could never have made a statement such as the one above. Alternatively, suppose there is only one type of חלזון in the world. In that case, should you discover a creature that classifies as חלזון, you can be certain you have discovered the חלזון התכלת. But we can safely reject this possibility, as we know of at least three types of חלזון:

1. The חלזון התכלת, which lives in the sea.
2. The Talmud in Sanhedrin (91a), in a completely different context states, "Go up to the mountain and see - today there is but one חלזון. Tomorrow it will rain, and the mountain will be filled with חלזונות. The Yad Ramah (ad. loc.) comments, "It is logical that this Chilazon is not the one mentioned with respect to Techeiles... Rather it is logical that we speak here of a different species... It is called in Arabic 'Chalzum'"
3. The Ritva (Shabbos 75a) mentions a third type of חלזון in the context of the laws of killing an חלזון on Shabbos - "The Chilazon is differen since it has no limbs. Rather it is a sealed body, like the Chilazon [that lives] in the garbage dumps.

This leads us to the conclusion that חלזון is a generic term, in which case, any species of חלזון that produces a תכלת dye (with specific requirements which we will not address here at this time) must be valid as per the aforementioned Tosefta. The same conclusion can be drawn from the following story recorded in the Talmud (Menachos 43a):

"מר ממשכי אייתי תכלתא בשני רב אחאי, בדקוה בדרב יצחק בדר"י ואיפרד חזותיה, בדרב אדא ואישתני למעליותא. סבר למפסלה. אמר להו רב אחאי, אלא הא לא תכילתא היא ולא קלא אילן היא?! אלא שמע מינה שמועתא אהדדי איתמר, היכא דבדקנא בדרב יצחק בריה דרב יהודה לא איפרד חזותיה כשרה, איפרד חזותיה, בדקינן לה בדרב אדא בחמירא ארכסא, אישתני למעליותא כשרה, לגריעותא פסולה"

"Mar of Mischi, brought Techeiles in the days of Rav Achai. When subjected to the test of Rav Yitzchak it faded [i.e. failed], but when subjected to the test of Rav Ada [its colour] improved [i.e. passed]. Rav Achai exclaimed, 'This is neither Techeiles or plant indigo?!' Rather, both tests are used together. [First] when you subject it to the test of R' Yitzchak, it its colour does not fade it is valid. If it fades, then subject it to the test of R' Ada. If it improves, it is valid, if it fades [more] it is invalid".

We see from this Gemara, that any fabric dyed the colour of תכלת was assumed to be either plant indigo (i.e. invalid) or authentic תכלת. This is so, to the extent that Rav Achai was flabbergasted when the fabric passed one test, but not the second. From this they concluded that the two tests (which are described in the Gemara there) are to be used in tandem. From this we may conclude, that any dye that we know was used in the times of the Gemara to produce תכלת-coloured garments, as long as it can be proven that it is not plant indigo, can be assumed to be valid for תכלת. Otherwise, Rav Achai would have been worried that the תכלת-dye came from a חלזון that is invalid.

That leaves us with two questions, to be addressed in future posts: Is the Murex Trunculus the חלזון that was used in the times of Chazal for producing תכלת? And if not, does it classify as a species of חלזון, in which case it is valid, regardless of what the historical חלזון התכלת was? If you answer yes to either of the above, then you should be wearing תכלת on your ציצית, unless of course you accept the מסורה argument, in which case, even if it was valid, you wouldn't wear it because your father didn't, שאל אביך ויגדך*.

* On the topic of שאל אביך ויגדך, my father suggested that R' Soloveitchik's argument works only when there is a מקום ספק. When there is some degree of uncertainty, the default position follows מסורה**. But if there would be 100% conclusive evidence that the Murex is valid for תכלת, even R' Soloveitchik would agree. (I would add, that for R' Soloveitchik, 100% evidence would need to include 100% halachic evidence.)

** The implicit assumption in my father's suggestion is that the מסורה of שאל אביך ויגדך is a הכרעה, not a בירור.