The gemara notes a machlokes between Rebbi and R' Yosi B"R Yehudah regarding the materials appropriate for the menora (and by extension other kli shares). The essence of the machlokes revolves around how similar the analogy resulting from a ribui-miut-vribui vs. klall-prat-klall is. As I understand it a ribui-miut-ribui is more inclusive but does exclude things which are "far afield". In this instance kli cheres is excluded but etz is OK.
What disturbs me is I lack an understanding of the paramaters which are used to define the categtory. ie why say cheres is excluded, perhaps it should be included and only something like kli glalim is meant to be excluded. How does one know where to "draw the line"? (I suspect one can ask a similar question re klal uprat) To answer that there is a mesora as to what is included or excluded doesn't seem acceptable as my understanding of these drashos is that one need not have a specific mesora to make a limud of this sort.
Gary Schreiber, Chicago
You are asking a general question on the rule of Klal Perat u'Kelal as well as a specific question on this Sugya.
(a) To answer your general question, I found and important Tosfos in Eruvin (15b DH Mah), which touches on this point. He explains that the Klal Perat u'Kelal written with regard to a Get is explained as excluding a living being or food from being used; the Klal Perat u'Kelal of Ma'aser Sheni teaches that it must be an item that multiplies and grows from the gournd, and with regard to Chagigah we exclude what is Mekabel Tum'ah and does not grow from the ground. Why didn't we use the same criteria in all three cases (since they would seem to apply by all of them)?
Tosfos answers that it all depends on "what the chachamim saw fit," as the case may be. That is, the Torah relies on us to use logic to explain every single Mi'ut or Ribuy in the Torah. When it comes to Klal Perat u'Kelal, it is necessary to define *logical* paramaters for what kind of thing ought to limit the Halachah under discussion, and only after that to decide how much to limit the Halachah, based on the 13 Midos.
In our case, that means that Chachamim decided that there are three categories: wood, metal, and precious metals.
(b) As for your specific question on our Sugya (why isn't Kli Gelalim a fourth category), perhaps the answer is what we say in Pitum ha'Ketores (Krisus 6a); urine was not allowed in the Mikdash out of respect. Since the same applies to excrement, it is not necessary for a verse to exclude using it for Klei Shares.