Siman Or Sibah

There is a chakirah if the simonim of a non-kosher animal are as the word simonim-sign applies, an indicator that the animal is tamah or the signs actually cause the tumah (see Likutay Sichos volume 1 in name of the Rogatchover.)   The Gemorah in Chullin 42b says that Moshe was shown all the of the animals and told if they were muttur or assur.  Why was this necessary?  The Maharal explains because the simonim just indicate the tumah, Moshe was revealed the cause of the tumah as well. He assumes the simonim are merely indicators, not causes.  

On the other hand, the Gemorah in Niddah 51b says that the Torah wrote fins and scales, even though all that have scales have fins, “lehagdil Torah veyadir.”  The Ritvah understands this to mean that the Torah was identifying the causes of the tumah which are the simonim.  In other words, the Ritvah understands that the simanim are a aebah, the cause of the tumah.  The midrash and Ramban ask if the Torah tells us animals with one siman are tamah, for sure animals without any simanim are tameh, why did the Torah did to say they are tameh?  If simanim are merely an indicator then there is no kal v'chomer because more indicators doesn't actually affect the din.  Since they assume it is a kal v'chomer it would seem that they hold as well that the simanim are indeed a sebah, the cause of the tumah.  However, possibly the answer of the Ramban is to be understood to be making this point that the simanim are merely simanim (see it inside.)

The Rambam counts a mitzvah to know the simanim of grasshoppers, birds, fish and animals as separate positive commandments (#149-152.)  (The Kesef Mishne (beginning of Maacalos Asuros,) Bach beginning of siman 79 and others debate if it’s a commandment just to know the simanim or its just if one wants to eat then they must verify that its kosher.)  If the mitzvah is merely to know the simanim of the animals, why is there a separate mitzvah for each animal, it should be just one mitzvah to check simanim?  It would seem from here that the Rambam holds that the simanim are a sibah, it causes the issur and therefore one must identify each cause.  This would be strengthened by the Rambam Maacalos Assuris 2:1 which cites the same derasha as Rashi does on 11:8 that if there is a lav to eat the animals that have one siman it is a kal v’chomer that animals without any simanim are prohibited by a lav.  If they are merely simanim then there is no kal v’chomer for an animal with one siman isn’t closer to being permitted more than one without any simanim.  We see from here again that he holds the simanim are causing the tumah and it is a valid kal v’chomer for the animal with one siman has part of the cause of taharah and still is prohibited, for sure that which has no cause of taharah is prohibited.