The origins of moral thinking and behavior have been a perennial source of dispute. In these discussions, two distinct questions arise. First, one can inquire whether moral standards are universal in nature or reflect local cultural conditions. An independent issue is the source of morality—can it be derived in a purely intellectual manner or does it rely on instinct/intuition? In this essay, I will focus on the second problem and argue that Rabbinic moral psychology presents a more complex picture that incorporates a feedback loop connecting reason and passion.
Expanding on this issue, there are two competing theories for the source of morality. One line of thinking asserts that human beings possess the ability to discern moral behavior through the use of their rational capacity. The alternative is to give priority to human passions and to recognize that rational thought and justification come after nearly automatic, pre-cognitive mental processes.
An instinctive basis for moral behavior has found recent expression in two distinct but overlapping formulations. Leon Kass has emphasized the importance of feelings of repugnance as a final line of defense in defining immoral behavior in modern contexts where established rules and guidelines seem to be thinning out and provide weak defense against unethical activity. The “yuck factor” is a term that Arthur Caplan has coined to viscerally describe our reaction when encountering something violating our moral sensibility. Like Potter Stewart on pornography (Jacobellis v. Ohio, 378 U.S. 184 (1964)), neither Kass nor Caplan offer a strict definition of repugnance or the yuck factor. Instead, they appeal to a gut feeling that says something is very wrong and should prompt behavior to correct it, what we would then call moral action.
Jonathan Haidt, in The Righteous Mind, comes down strongly on the side of instinct driving intellectual rationalization for behavior. Superimposed intellectual adaptations can overlay instinct, restrain our selfish inclinations and channel them in ways that enable social groups to survive. However, they do not aim to alter our fundamental impulses. Haidt’s extensive psychological research studies, in widely varying settings, lend strong experimental support to this conclusion. He demonstrates how a variety of moral foundations including equality, authority, and sacral notions can be mobilized to promote and support moral group behaviors that maintain community health and function. The process is depicted as unidirectional—intuitive reactions foster rationalizations that generate communal rules that support the desired group behavior. Again, the implication is that the automatic instantaneous, non-thinking reactions, while they may be dampened, are not changed by rational thought. I suggest that the legal code and moral foundations in the Torah and Rabbinic thought challenge this simple formulation. They embrace a bidirectional interaction between reason and passion, with each of these psychological components serially modulating and modifying human behavior towards a feasible moral goal.
There is always a concern for anachronistic thinking when applying terms used in the intellectual parlance of 2019 to people who lived two millennia ago. Terms like yuck factor and group selection are not in the Rabbinic lexicon. However, I would suggest that the ancient Jewish law recognized the importance of human factors—instinctive, impulsive, and emotional in nature—in defining the content and enforcement of the legal code that they considered revealed by God at Sinai. At times, the Rabbis modulated these non-rational behaviors and at other times they tried to alter and redirect them towards more intellectually sound practice.
For most people living on the planet today, child sacrifice would provoke revulsion, an instinctive reaction that it is terribly wrong and should never be done. It would violate all notions of morality. The Torah articulates a different standard. According to most of the biblical commentators, the purpose of the Akeida (binding of Isaac) was not to have Abraham obey the command to sacrifice his son but rather to serve as a challenge, extreme to be sure, to his religious faith in God. The angel unequivocally calls out to him to spare his son (Genesis 22:11–12). Abraham responds immediately in the next verse by spotting the ram caught in the in the underbrush and sacrificing the animal instead. The Torah explicitly prohibits the cultic practice of Moloch which centered on child sacrifice (Leviticus 20:3).
We cannot enter the minds of people living 4,000 years ago and we cannot know whether child sacrifice was thought to be a reasonable and necessary act to appease the gods and prevent greater harm to the community. Nevertheless, these texts do indicate that in ancient times, it did not trigger the same abhorrent feelings that we experience at the thought of killing a child. Today it is inconceivable to kill a child for any reason. True stories from the Holocaust, along with novels like William Styron’s Sophie’s Choice portray the psychic costs of this repugnant act. The Torah mandated a new moral standard and made the rational assertion that, while obedience to divine command was the measure of religious commitment, heteronomy did not extend to killing a child. This represented an educational move to alter people’s instinctive reaction and to provoke feelings of repugnance when confronted by the practice of child sacrifice.
In a similar vein, in Leviticus (Chapter 20) the Torah prohibits a long list of sexual relations, some of which are described as abominations. This choice of words sounds like the Torah is basing itself on an instinctive aversion to these acts. But according to Maimonides there was a rational purpose, namely to force men to alter their nature, prevent abuse of women to whom they had easy access, and establish more permanent family ties to wife and children (Guide for the Perplexed, 3:49). In Deuteronomy, Chapter 21, the law addresses the circumstance of a soldier who becomes infatuated with a woman captured in war. The instinctive response was to take full advantage of the conqueror’s status and ravage the captive. But the law mandates a separation period to defuse the urge to hurt the woman and encourage the formation of a more stable marital relationship. In this instance, this alternative is an improvement on the behavior of the time but still falls short of modern moral sensibilities. In each of these two circumstances, the Torah is providing an intellectual basis for transforming what had previously been considered normal operating procedure for men and women—no restrictions on sexual intercourse, raping women captured in war—into one that would trigger the yuck factor. In all of the cases, there is an intellectual justification upstream of an intuitive reaction that is formulated to change what is considered revolting and the altering the received passions.
Does the Rabbinic literature present a similar picture in which the law is promulgated in opposition to what would be considered the instinctive behavior? The answer is yes and the formulation of the response occurs in two steps. To start, the Rabbis did not view their intricate legal code to be static and unresponsive to human input. In her innovative book, What’s Divine about Divine Law? Early Perspectives, Christine Hayes compares the Greek and Rabbinic conceptions of divine law. For the Greeks, what made divine law divine was its correspondence to absolute truth, its unchanging character, and its universal applicability. Hayes shows how the Rabbis challenged each of these characteristics and welcomed human partnership in the formulation and practice of divine law. Her examples include the famous confrontation between Rabban Gamliel and Rabbi Yehoshua about the date of the New Year (Rosh Hashanah 25a). Rabban Gamliel felt empowered to declare the date of the sighting of the new moon and to ignore any contradictory facts. This is consistent with authorization given to the people through their judicial institutions to define the timing of Rosh Hodesh (the new month) (Exodus Chapter 12:1–2, a law that is brought to life in the aforementioned Gemara). Correspondence to absolute celestial truth was not the determinative factor. His word as nasi (leader of the Sanhedrin ha-gadol—Jewish High Court) was final and Rabbi Yehoshua was obliged to abide by the artificial calendar against his reasoned assessment of the astronomical facts.
The requirement for kavana (knowledge that one is performing a Mitzvah) as a necessary factor for fulfilling specific mitzvot (see Rosh Ha-shana 28a–29a, Pesahim 114b, et al.) underscores, according to Hayes, Rabbinic nominalism, namely that there is no mind-independent reality for religious objects or practices. A person’s mental state can convert an action or an item from secular to holy. Even recognizing that the requirement for kavana is debated and far from uniform for all mitzvot, and regardless of whether one goes as far as Hayes does in her assertion, the impact of kavana clearly introduces a human element into the formulation of legal concepts, in contrast with the Greco-Roman view of the unchanging nature of divine law.
The expressions of the uniqueness of Jewish people throughout the Talmud fly in the face of the universality of the law. Hayes asserts that the Rabbis were of the mind that there is variation in people’s temperament and attitudes and that this is reflected in differences in the legal code and level of obligation between Jews and gentiles. She cites numerous cases in which the Rabbis altered the law based on what they thought was the best way to read and reify the cryptic Torah text. These amendments to Torah law were often an explicit acknowledgement that human instinctive reactions need to be taken into account to ensure stability and applicability of religious law. Not all of these points relate directly to the question at hand, namely, the source of morality. However, taken together, Hayes’ evidence that the Rabbinic conception of divine law embraced human input and undermined the three aspects (correspondence to truth, unchanging nature, and universality) that defined the Greco-Roman view creates an opening for a more complex picture of the development of moral psychology. It thus provides a foundation for the unique Rabbinic formulation of moral psychology.
In a second step, Rabbinic used their divinely sanctioned human input to steer previously acceptable instinctive behavior back to a more intellectually grounded, morally reasoned plane. The plain reading of the sentence in Shemot (Chapter 21), “an eye for an eye, tooth for a tooth, hand for hand, foot for foot” indicates that this was how justice was meted out after unwanted physical injury. But the Rabbis rejected this notion (Bava Kama 83a–84b). After much effort to logically justify the replacement of lex talionis that was likely the accepted practice in courts of surrounding cultures with the financial restitution that was the standard in Jewish courts, the Rabbis conclude it is svara, the rational conclusion. Similarly, the impulsive reaction to the accidental murder of a family member is anger and immediate retaliation. The extensive laws outlined in the second chapter of Masekhet Makot are designed to convert the prevailing culture from one that supported revenge-killing to one that protected a person who committed manslaughter.
Another example is the enactment of the prozbul, a rabbinic response to the immediate reluctance that creditors would feel if asked to loan money close to the end of the seven-year shemita (sabbatical) cycle and face potential loss of repayment (Gittin 37a, Yevamot 89b–90b). A person’s passionate attachment to his/her money needed to be accounted for in drafting practical legislation. But the ultimate goal was to ensure that people will not act on selfish impulses and deny credit to those in need of financial aid. Finally, all of the takanot (enactments) of Rabban Gamliel, detailed in Masechet Gittin, Chapter 4, which limit the options of husbands to inflict senseless harm on their wives during divorce proceedings, acknowledge the need to intellectually modify the destructive force of people’s instinctive reaction to insult and personal affronts.
The focus of this essay has been on the processes involved in the formulation of law, a complicated, multidimensional process. In any legal code, including the halakha, there are clearly rational laws, as well as others that openly accommodate people’s impulsive, non-rational behavior. In addition, there are some composite laws that engage both elements. For Haidt, the primary force in the construction of the vast majority of the remaining laws is instinctive behaviors coated with a modulating intellectual veneer (green lines in the figure). His view of this impulsive behavior is nuanced, and he defines six discrete domains that are foundational in people’s response and delineation of moral behavior—care, fairness, loyalty, authority, sanctity and liberty. He emphasizes this in his efforts to promote greater openness to understanding the variety of responses. But instinct and non-rational thought predominate, and can only be controlled, not changed. I suggest that one formative element is missing that is prominent in Rabbinic thinking, namely a category of laws that aims not simply to control but to convert instinct to reasoned behavior (blue lines in the figure).
In conclusion, moral psychologists like Jonathan Haidt are right in their emphasis on the key role of immediate intuitive passions versus rational thought in guiding the formulation of ethical codes and religious practice. I am disinclined to place relative percentages on the contribution of these “fast and slow” mental systems to the development of human morality. Instead, I would incorporate Christine Hayes’ insights about the premium the Rabbis placed on the human input into the divine Torah law.
I would go farther and advocate for a view of Rabbinic jurisprudence as a comprehensive feedback loop system in which reason can frame instinctive responses which then can modify rational law and accommodate human impulses. This circular loop links reason and passion in an adaptive system that ideally would be self-correcting. This arrangement is similar to nearly all biological processes that modulate body homeostasis. It gives new meaning to the phrase, sound body and sound mind. It is a conception of moral psychology that is neither too lofty so that man is unrecognizable or too low to make him/her indistinguishable from other creatures. The Rabbinic conception of religious law and moral behavior is a servo-nulling mechanism, “an automatic device that uses error-sensing negative feedback to correct the action of a mechanism.” It adjusts human passion and reason to achieve a legal code that presents human beings the best opportunity to live in accord with the divine will.
 Carlos Fraenkel, Philosophical Religions from Plato to Spinoza: Reason, Religion, and Autonomy (Cambridge: Cambridge University Press, 2012).
 Howard Kreisel H, Maimonides’ Political Thought: Studies in Ethics, Law and the Human Ideal, (New York: SUNY Press, 1999).
 Leon Kass, “The Wisdom of Repugnance,” The New Republic, June 2, 1997; 17–26.
 Charles W. Schmidt, “The Yuck Factor: When Disgust Meets Discovery,” Environmental Health Perspectives 116 (December 2018): A524–A527.
 Jonathan Haidt, The Righteous Mind: Why Good People Are Divided by Politics and Religion (New York: Pantheon, 2012).
 William Styron, Sophie’s Choice (New York: Random House, 1979).
 Christine Hayes, What’s Divine about Divine Law? Early Perspectives (New York: Princeton University Press, 2015).