From Kilayim to Kabbalah to CRISPR

I participated in a conference on the new gene-editing technology known as CRISPR/Cas9 at Berkeley on June 18-19, 2017. Below are my remarks, building on the foundation of my 2015 responsum on genetic engineering.

Gene Editing Ethics Workshop convened by Jennifer Doudna and Bill Hurlbut

Panel on Catholic, Muslim and Jewish Perspectives

(Texts displayed as slides; found below)

  1. I’m honored to have been invited to attend this conference and offer some comments on Jewish responses to gene editing. In addition to serving as dean of the JTS rabbinical school, I am a member of our denomination’s Committee on Jewish Law and Standards. In this capacity, I engage in writing responsa, which are essentially position papers on topics of halakhah, a Hebrew term which encompasses Jewish law, ethics and devotional life. In 2015 the CJLS approved my paper on genetic engineering, which touched on CRISPR/Cas9, but which requires greater inquiry, making this conference especially helpful to me.
  2. In searching for halakhic values and precedents of relevance to gene editing, I identified two discourses in tension, one which we may call preservationist, and the other interventionist. They begin from the same point of origin, shared with most peoples of faith, that life is not only precious but also sacred. The Bible and biblically-based religions go further, declaring human life to be fashioned in the divine image, בצלם אלהים, an ambiguous expression which nevertheless implies that humanity has God-like qualities and therefore great responsibilities. This core principle is the foundation of the special abhorrence for the crime of murder, and is also the basis for the obligation to do what we can to heal illness and extend human life. The idea of the divine image imposes an obligation to preserve human dignity and to prevent humiliation. The belief that life is sacred likewise grounds the prohibition on causing animals excessive suffering, prevents the wanton destruction of trees, and curbs the human tendency to eradicate species. Life is sacred, and humans are charged to be its custodians, a task for which we have proven to be spectacularly inept.
  3. That life is sacred is a point of easy consensus, but the nature of human stewardship proves more divisive. The preservationist school points to commandments such as Leviticus 19:19, the ban on mixing seeds and cross-breeding animals:

You shall heed my statutes: you shall not let your cattle mate with a different kind; you shall not sow your field with two kinds of seed; and clothing made of two kinds of yarn you shall not put on yourself.

  1. It is not evident what the Torah’s concern is here, but we can say that in general, the priestly sections of the Torah show an interest in border maintenance. The doctrine of holiness is built upon distinctions; the blending of species seems to offend the divine sense of order, and is therefore prohibited.
  2. The medieval sage known as Ramban, a 13C Spanish rabbi and physician, explained that cross-breeding species was an expression of arrogance—as if to say that the Creator did a poor job, and this person wishes to finish the task. Ramban hinted at something more mystical—that cross breeding would somehow undermine the work of creation.
  3. The classic of Jewish mysticism known as Zohar spells this concern out more fully—there is a link between material and spiritual reality, and a sort of divine patronage system over each life-form. Changing the nature of species can delink life from spirit, creature from Creator, leading to catastrophe.
  4. Of course, I do not expect a gathering of modern people, including prominent scientists and lawyers, to worry too much about the mystical concerns of a medieval classic, but the Zohar is not alone in worrying that changing the genetic makeup of life forms can have unforeseen consequences.
  5. Harvard philosopher Michael Sandel argued in his book, The Case Against Perfection, that enhancements to the human genome may lead to an attitude of hyper-agency. This in turn may undermine the sense of the giftedness of life, that is a foundation of both religious and secular ethics. A result of this preservationist perspective would be extreme caution and even suspicion of the gene editing enterprise and of CRISPR/Cas9.
  6. However, there is another discourse within Jewish sources which I have dubbed the interventionist or adaptive approach. These sages delineate a more active form of stewardship in which the task is precisely what worried Ramban—to co-create the world and make it more perfect. We see this in the writings of the 16th century rabbi known as Maharal of Prague, who is famously associated with the legend of the Golem. He argued that while Jewish law may prohibit the blending of species, God instructed Adam to do precisely that, in breeding a mule, because this would perfect the world.
  7. More generally, this interventionist perspective is what allows for the practice of medicine. Nature is not considered to be static, and stewardship calls for more than preservation. We live in a dynamic environment, and adaptation is the key to survival. If new therapies are invented which can prevent disease and enhance life, then they would be not only permitted but even required.
  8. There, I used the word “enhanced.” The distinction between therapy and enhancement seems highly problematic to me. Of course, we do not want to exacerbate our society’s already excessive concerns with beauty and physical prowess, or to deepen the already intolerable social divides of economic class and access to adaptive technologies. However, making our bodies more resilient and our minds more vibrant throughout life is an enhancement that most people would value. The interventionist ethic would cheer on CRISPR, so long as due caution is taken not to cause more harm than good, and not to commodify life to the point that its sanctity is undermined.
  9. Between these two discourses lies a middle path of wisdom. We don’t seem to know enough yet what would be the long-term impact of making permanent edits to the genome, whether of humans or of other life-forms. Caution and humility are called for, but inaction is also not an option. If we can invest our contemporary discourse with a sense of respect and even reverence for life, as Bill Hurlbut did in his opening remarks, and if we can articulate policies that could limit the dangers of excessive intervention, making the minimal changes needed to avert specific maladies, then there is a chance we might emerge from this with both our bodies and spirits intact.
  10. In 1940 the Jewish Theological Seminary hosted a conference on “Science, Technology and Religion.” Albert Einstein said that, “Even though the realms of religion and science are clearly marked off from each other, nevertheless there exist between the two strong reciprocal relationships and tendencies.”[1] Einstein spoke of the mutual quest for truth and understanding. He also intimated at the dangers posed by untrammeled efforts of scientists and religious leaders, who are capable of both great good and great evil. In concert, perhaps, we can elicit the best from one another, curbing excesses before they lead to tragedy. I hope that these brief comments may offer some useful perspective, and look forward to learning more from the pioneers of this powerful new technology.



I Preservationist Discourse

Leviticus 19:19

You shall heed my statutes: you shall not let your cattle mate with a different kind; you shall not sow your field with two kinds of seed; and clothing made of two kinds of yarn you shall not put on yourself. [different kinds=kilayim]

Nahmanides (Ramban, R’ Moshe b. Nahman, b. Girona 1194-1270),

Bible Commentary to Lev. 19:19.

But when one grafts two different species, he alters and undermines the work of creation, and it is as if he thinks that the Holy One did not complete the work as needed, and now he wants to help in the creation of the world by adding new creatures to it.

Zohar (13C, Castille) to Kedoshim, III: 86b[2]

Thus it is written huqqotai, My statutes you shall keep. [Your cattle you shall not mate kilayim with a different kind; your field you shall not sow kilayim, with two kinds; two kinds of threads—shatnez–shall not come upon you] (Lev. 19:19)—because every single one is appointed over a specific object in the world by that hoq. Consequently, it is forbidden to switch species, to insert one species into another, because one thereby uproots each power from its place and negates the celestial family, falsifying the royal solemnity.

Michael Sandel, The Case Against Perfection: Ethics in the Age of Genetic Engineering

Hyperagency is, “a Promethean aspiration to remake nature, including human nature, to serve our purposes and satisfy our desires. The problem is not the drift to mechanism but the drive to mastery. And what the drive to mastery misses and may even destroy is an appreciation of the gifted character of human powers and achievements.” (26-27)


II. Interventionist Discourse

Psalm 8

What are humans, that You have been mindful of them, mortals, that You have taken note of them, that You have made them little less than divine, and adorned them with glory and majesty; You have made them master over Your handiwork, laying the world at their feet, sheep and oxen, all of them, and wild beasts too; the birds of the heavens, the fish of the sea, whatever travels the paths of the seas. O Lord, our Lord, how majestic is Your name throughout the earth! (Psalm 8: 5-10)


Midrash Bereshit Rabbati, Vayetzei.

That you have made them little less than divine—This refers to Jacob, for it says (in Genesis 30:39), and since the goats mated by the rods…. Rabbi Hoshaya explains, “He would draw an image, and just as he drew, so the seed formed in the water of their wombs, and so did they give birth. This teaches that [Jacob] lacked only the ability to give them a soul.”


Maharal (R’ Judah Lowe, c. 1512-1609, Prague), Be’er HaGolah II:10.

As for those who are surprised by [God’s instruction to Adam for] grafting of two species, certainly according to the Torah given by the Holy One to Israel this practice is forbidden as kilayim (Lev. 19:19). But Adam the First was to do this act, because this [new species] deserved to be in the world, so that the world would be completed.

[1] Quoted from Robert Pollack, “How the Unconscious Shaped Modern Genomic Science,” in Jews and Genes: The Genetic Future in Contemporary Jewish Thought, edited by Elliot N. Dorff and Laurie Zoloth, JPS, 2015.

[2] Translation by Daniel Matt, The Zohar: Pritzker Edition, Volume 8 (Stanford UP, 2014), pp.39-40. See notes 115, 116 and 117.