The Gemora on 79a discusses a house that is 10 tevochim high. That is at most 40 inches high. This would make sense it it were a doghouse, or if people in the times of the Gemorah were two feet high. This is a continuation of the discussion in the previous pages, where the Gemora treats a 10 tevochim wall as if it were a real barrier to social behavior, and which the Gemorah (77a) says usage of its top surface is inconvenient. This too makes sense if people were midgets.
For people of today's size, placing something on a wall that is 40 inches high is perfectly convenient. Furthermore, the Gemora discusses the role of a ladder against a wall. The picture in Tosfos on 78a implies a very tall ladder with a tall wall, but the Gemora was also discussing using a ladder against a 40 inch wall, stating that the ladder bridges the two properties into one social unit. Nowadays, any normal person can straddle a 40 inch wall. So one might think that people in times of the Gemora were all two feet midgets - but I think there are many proofs to the contrary. If so,how is all of the above explained? (Especially according to the opinions that ten tevochim is around 32 inches)
Avrohom Meyer Kohn, Los Angeles, CA
The people in the time of the Gemara were clearly not midgets (as you indicated, see Rashi in Shabbos 92a, DH "Ishtakach").
The main reason that a ten Tefach wall separates between two domains is because it is clear that a wall of ten Tefachim is considered a Mechitzah according to Torah law (either via a teaching from the Aron or a Halachah l'Moshe mi'Sinai, see Sukah 4b-5b).
By nature, a Mechitzah separates between two places. Though it was not necessarily common to use such walls in the time of the Gemara for houses, a ten Tefach wall is often discussed in the Gemara as it is the minimum valid height of a wall (i.e. a Sukah can be ten Tefachim tall, see Sukah 2a).
Regarding the case on 77a, it does not seem that the Gemara was pronouncing the usage of the wall inconvenient in general when it labels it "Tashmisho Kashah" -- "its usage is difficult." Rather, it seems to refer to whether or not it becomes one Reshus and is usable with the surface that it is closest to, namely the Chatzer in question. If it is closer to being level to the surface in question, it is easier to become used as the Chatzer is used. If not, then it is labeled relatively "Tashmisho Kasha."
The Gemara on 78a is less difficult. Being that there is a Mechitzah which divides between the two domains, there is automatically a separation between the two domains. The Rabanan established various leniencies (in the Rabinnic decrees of Eruvin) in order to unite the two Chatzeros, including making a ladder "Pesach" to enable people to get past the Mechitzah in an easier fashion. However, the Mechitzah should definitely separate the two Chatzeiros, as it does in all other cases in Torah law.
All the best,