Rabbi Slifkin’s strident and ongoing disparagement of Chazal's wisdom remains unchecked. This is demonstrated most keenly in his treatment of the halachic definition of death. In this recent post, Rabbi Slifkin reiterates several of his previous assertions regarding this issue and even adds one for good measure. His shoddy scholarship is actually shocking. Here are a few examples.
And so, while Dr. Stadlan is absolutely correct to state that when babies are born with extra appendages or organs, they are considered to be two persons when they have two heads - it should be noted that Chazal did not view it that way!
This is unbelievable! Anyone opening a gemara Menachos 37a-b will see that a two-headed firstborn requires 10 selaim for pidyon haben! This gemara is juxtaposed with Rabbi Slifkin’s gemara regarding Palemo and Rebbi. If anything, this gemara can be brought as proof that Chazal understood a two-headed person as two distinct persons, not one.
In my monograph The Question of the Kidneys' Counsel, I showed how Chazal believed that significant components of the mind are located in the chest cavity - in the heart, kidneys, and other innards - rather than in the brain.
This assertion was already refuted here and here and yet Rabbi Slifkin continues to repeat the same error. Incidentally, Rabbi Slifkin did not claim that “significant components of the mind are located in the heart, kidneys, and other innards - rather than in the brain”. He claimed that Chazal believed that the mind was located in the heart and kidneys and not the brain, period. He seems to be engaging in some creative back-pedaling.
Accordingly, dicephalus twins — conjoined twins with a single trunk and one head — were regarded as a single person with two heads. We see this in the way that the Gemara presents the question mentioned above. The Gemara discusses the question of upon which head such a person (described in the singular!) should place tefillin.
We see nothing of the sort. Mee'ma nafshach; even if Palemo and the rest of Chazal held that a two headed person was definitely only one person, Palemo should still have asked the question differently. He should have asked, “Does a two-headed person need to put tefilin on both heads or can he be yotzeh the mitvah by putting on tefilin on one head”? The format of Palemo’s question is equally puzzling regardless of Chazal’s position regarding “two-headed personage”. Accordingly, Rabbi Slifkin’s “proof” is no proof at all.