Eruvin 18a ~ Adam's Tail and the the Recapitulation of Phylogeny

On today’s page of Talmud we read the following:

כְּתִיב: ״וַיִּבֶן ה׳ אֱלֹהִים אֶת הַצֵּלָע וְגוֹ׳״, רַב וּשְׁמוּאֵל: חַד אָמַר פַּרְצוּף, וְחַד אָמַר זָנָב 

 it is written: “And the tzela, which the Lord, God, had taken from the man, He made a woman, and brought her unto the man” (Genesis 2:22). Rav and Shmuel disagree over the meaning of the word tzela: One said: It means a female face, from which God created Eve; and one said: Adam was created with a tail [zanav], which God removed from him and from which He created Eve.

The Talmud then investigates how the claim that Adam was created with a tail can be supported from the text of the Bible, and it is a discussion that need not concern us here. But Tosafot actually takes the time to consider which of the two explanations of the word tzela is correct, and concludes that it is the opinion that Primordial Man was indeed created with a tail, from which Primordial Eve was created.

The suggestion that for a time, Primordial Man had a tail is actually well known to those who study embryology and human development. To understand why, we need to take a detour into the thought of a German named Ernst Haeckel (1834-1919) who, at least according to Wikipedia, was a “zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist, and artist.”

Ernst Haeckel - A warning

Before we go any further, we must point out that Haeckel was a social Darwinist, and an advocate of scientific racism. He believed that some human races were inferior to others, as this sample from his book The Wonder of Life makes abundantly clear:

These lower races (such as the Veddahs or the Australian negroes) are psychologically nearer to the mammals (apes or dogs) than to civilized Europeans; we must therefore assign a totally different value to their lives.

The fact that Haeckel thought that the Jews were located “at the same highly developed level as the Germans and within the same species” should not comfort us. Scientific racism is malodorous and to be fought at every turn, regardless of which race or group are claimed to be at the top. We, of all peoples, should know this to be true. So to quote Haeckel in a post about the Talmud might be just too distasteful for some. If this resonates with you, please read no further, and join us again for the next post, which will discuss telescopes. But if you can hold your nose for a while, read on and see why Haeckel springs to mind when learning that Adam was created with a tail.

[Haeckel’s] evolutionary racism; his call to the German people for racial purity and unflinching devotion to a ‘just’ state; his belief that harsh, inexorable laws of evolution ruled human civilization and nature alike, conferring upon favored races the right to dominate others ... all contributed to the rise of Nazism
— Stephen J. Gould . Ontogeny and Phylogeny. Harvard University Press 1977. 77.

Ontogeny Recapitulates Phylogeny

Haeckel’s contribution to science was his suggestion (now largely discredited or re-interpreted) that “ontogeny recapitulates phylogeny.” Ontogeny is the study of the organization and development of an organism; phylogeny is the study of how a species evolves. The meaning of this phrase boils down to this: as an organism grows inside the womb, or the egg or whatever, it goes through stages that mimic the previous development of its species over millions of years. The theory was especially pertinent to higher animals, like mammals, which, so the claim goes, go through embryological stages analogous to the adult stages of organisms from those species in its evolutionary history.

Haeckel believed that when you look very closely at the development of a human embryo, there are several stages in which it appears to have more in common with a fish, a species thought to have been ancestors of humans. His textbooks contained illustrations of this principal, like this one:

TOP LEFT: Dog (left) and human (right) embryos at 4weeksTOP RIGHT: Dog (left) at six weeks, human (right) at eight weeks.BOTTOM RIGHT:  Turtle (right) at six weeks, dog (left) at eight weeks.From Haeckel, E.

TOP LEFT: Dog (left) and human (right) embryos at 4weeks

TOP RIGHT: Dog (left) at six weeks, human (right) at eight weeks.

BOTTOM RIGHT: Turtle (right) at six weeks, dog (left) at eight weeks.

From Haeckel, E.

As you can see from the illustration, the dog and the human embryo resemble one another in the early stages of development, tails and all. Haeckel also observed that during a period of its development, the human embryo temporarily has slits on the sides of its neck, which resemble fish gills. This was an echo, he claimed, of our origins from fish.

Adam and his tail

So if Adam was created with a tail (as indeed Tosafot rules to be the case), does this lend support to the suggestion that ontogeny recapitulates phylogeny? Might the tail of the human embryo be an echo of this distant past in the Garden of Eden?

No. First, the creation story told in the opening of the Torah cannot be easily reconciled with the scientific understanding of human evolution. They are two different domains, and for every example where the order of creation seems to foreshadow what we now understand to be the story of the creation of the universe, there are many more examples that simply cannot be reconciled with our scientific understanding of how we got here. The great Rabbi Shimshon Raphael Hirsch (d. 1888) wrote that “it is not the aim of the Holy Scriptures to teach us astronomy, cosmogony or physics, but only to guide man to the fulfillment of his life’s task within the framework of the constellation of his existence.” To his list of things that the Torah does not teach us about, we should add evolution.

But there is a second reason why Adam’s tail cannot be found in the developing human embryo. It is because Haeckel seems to have been not altogether accurate in how he depicted the stages of development. Some have accused him of outright deception, while others more generously blame the poor equipment with which Haeckel had to work.

True human tails are rarely encountered in medicine. At the time when Darwin’s theory of evolution was a matter of debate, hundreds of dubious cases were reported. The presence of a tail in a human being was considered by evolutionists as an example that “ontogeny recapitulates phylogeny.” As the discussions on Darwin’s theory subsided, so did the reports on this interesting feature. A recent review summarized 33 cases of patients with a bona fide tail.
— Speigelman R. et al. The human tail: a benign stigma. J Neurosurg 63:461-462, 1985.

But humans do sometimes have tails

Sometimes babies are born with a defect that resembles a tail. Here, for example, is a photo from a 1985 case reported from the Department of Neurosurgery at The Chaim Sheba Medical Center and The Sackler School of Medicine in Israel.

From Speigelman R. et al. The human tail: a benign stigma. J Neurosurg 63:461-462, 1985.

From Speigelman R. et al. The human tail: a benign stigma. J Neurosurg 63:461-462, 1985.

The “tail” on this baby, and on others reported, contained no bones or vestigial spinal cord. It was largely made up of fatty (adipose) tissue, and did not connect to the spinal cord. It was removed surgically without incident.

The Israeli authors point out that the normal human embryo has a tail protruding from the trunk, and that

during the 7th to 8th week of embryogenesis, the tail regresses as the vertebrated portion retracts into the trunk and the caudal vertebrae fuse to form the coccyx. The nonvertebrated apex remains as a temporary pro- trusion, but finally also disappears. In 1901, Harrison suggested that the rare vestigial human tail probably arises from this distal, unvertebrated portion of the embryonic tail. This possibility could explain the two features noted in all reported human tails: namely, the lack of vertebrae and the absence of associated spinal cord malformations.

Another case report of a human tail, published in The New England Journal of Medicine in 1982, notes that this malformation provides no support for Haeckel’s theory. The rudimentary tail contains no bones, has no connection to the rest of the skeleton, and is often not even located in the midline. It is a reminder, the author claims, that some elements needed for the formation of a tail are somehow buried deep in our genes, because we are related to other tailed primates, from whom we diverged “some 25 million years ago.” Perhaps they are a rare reminder too that in Jewish thought, there is no shame in having a tail. Just ask Adam.

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