The Evolution of Disgust

Part Of: Affective Neuroscience sequence
Content Summary: 1400 words, 14 min read.

Introduction

Why did disgust evolve? Why does it play a role in morality? Should it?

 One of the best ways to understand an emotion is to build a behavioral profile: a list of its responses (outputs) and elicitors (inputs).

Disgust Responses

One of the striking features of disgust is how diverse its set of responses. These include an affect program:

  • Gape face. This is characterized by a nose wrinkle, extension of the tongue, and wrinkle upper brow.
  • Feeling of nausea. In fact, the physiological signature of intense disgust closely matches physical nausea.
  • A withdrawal reflex. This reflex need not be physical retreat, but can also yield motivation to remove the offending object.

But disgust also produces an inferential signature:

  • Sense of oral incorporation. That is, the subjective feeling that the offending object is already in one’s mouth.
  • Offensiveness tagging. Even after the object has been removed, it will continue to be treated as offensive indefinitely.
  • Asymmetric transmission logic. See the law of contagion: a clean object that touches something gross is contaminated, but not vice versa.

Disgust Elicitors

Even more diverse than its outputs, the elicitors of disgust include cultural universals, including:

  • Organic decay.
  • People and objects associated with illness
  • Compromised body envelope. These include: cuts, gashes, lesions, or open sores.
  • Substances that have left the body. These include feces, vomit, spit.  

Swallowing the saliva that is currently in your mouth is innocuous, but even imagining yourself drinking a glass of spit (even if it is (was?) your own, is disgusting. These last two elicitors are body perimeter tracking: they not only police the boundaries of the body in peripersonal space, but also seem to enforce a no re-entry policy: anything that exits or becomes detached triggers it.

There exists another suite of elicitors that are culturally tuned

  • Specific foods.  Some foods are deemed disgusting even when they have never been tried (e.g., liver).
  • Specific living animals. These can include: flies, maggots, worms, rates, lice, tics, slugs, snails, and spiders…
  • Specific sexual practices. These can include: homosexuality, pedophilia, bestiality, necrophilia, …
  • Specific morphological signatures. Deviations from bodily normality, however that is construed in a particular culture. These can include: the elderly, disabled, little people, …

It is worth emphasizes that disgust over sexual practices and morphological signatures varies widely across cultures and across individuals. For example, ancient Greece mostly didn’t find homosexuality disgusting but 20th century Americana mostly did.

Finally, people comprise another category of elicitors.

  • Moral transgressors. These can include: murderers, rapists, …
  • Members of an out-group. These can include: untouchable caste, Jews (in Nazi Germany), …

Neuroscientific data suggest that, when people are deemed sufficiently disgusting, brain areas associated with mindreading become deactivated. This is likely the neural basis of dehumanization.

The Entanglement Thesis

Taken together, here is the behavioral profile of disgust:

disgust_ behavioral profile

Puzzle: Why should the sight of a person with leprosy evoke a gape face and a feeling of nausea? Leprosy has nothing to do with digestion.

Solution: Disgust is a kludge! It is the unholy merger of two separate systems.

Poison monitoring is a faculty of the digestive system. It evolved to regulate food intake and protect the gut against ingested substances that are poisonous or otherwise harmful. It was designed to expel substances entering the gastrointestinal system via the mouth. It also acquires new elicitors very quickly.

Infection avoidance is a faculty of the immune system. It evolved to protect against infection from pathogens and parasites, by avoiding them. Not specific to ingestion, but serves to guard against coming into close physical proximity with infectious agents. This involves avoiding not only visible pathogens and parasites, but also places, substances and other organisms that might be harboring them.

Any theory of disgust should explain the unity of responses to disgust. Here is how entanglement theory does it:

  • Poison monitoring produces the affect program. Gape face, nausea and withdrawal all serve digestive (and not immunological) purposes.
  • Infection avoidance produces (most of) the inferential signature. The tendency to monitor disgusting things even when not immediately exposed, and the asymmetric logic of contamination, make perfect sense when tracking the spread of parasites.

Any theory of disgust should explain the diversity of elicitors of disgust. Here is how entanglement theory does it:

  • Poison monitoring is sensitive to certain foods (namely, those that are associated with toxicity)
  • Infection avoidance explains the aversion to certain living animals (flies are more likely to carry disease than dogs), apparently disease-infected substances, to certain sexual practices (sexual practices can bring increased risk of disease) and morphological deviations (e.g., violates of facial symmetry correlate with parasites). It also explains the general tendency for disgust to monitor the body perimeter: which is, after all, how pathogens can enter the body!

Any theory of disgust should explain cultural variation of the elicitors. Here is how entanglement theory does it:

  • The poison monitoring system is very quick to learn features the Garcia effect: one-shot learning.
  • In women, aversion to deviant sexual practices (and not other forms of disgust) vary with where they are in the ovulation cycle.

disgust_ entanglement thesis

Besides the increase in explanatory power, phylogenetic and ontogenic data also support the independence of these two systems:

  • Researchers disagree whether disgust is unique to humans, or whether homologies exist in the animal kingdom. Both are right: animals show clear signs of the existence of both systems but the systems are expressed separately.
  • Ever wonder why children don’t seem to mind disgusting objects & behaviors? It is because poison monitoring appear very early (within first year of life) but infection avoidance emerges significantly later.

The Evolution of Disgust

Why should the poison avoidance and pathogen monitoring have become entangled in the course of human evolution? Why didn’t poison avoidance become entangled with e.g., FEAR instead?

First, the two systems both care about digestion. Food intake can bring both poison and pathogens into the body, and as such it is monitored by both systems.

Why did entanglement only happen in humans, specifically? Compared to other primates, early hominids adopted a unique lifestyle, that combined scavenging with a nascent ultrasociality. These two characteristics put enormous adaptive pressure on the pathogen avoidance system to innovate.

Perhaps the most important reason for entanglement has to do with signaling. As hominids began to increasingly emphasize social cooperation, there became a need to communicate pathogenic information. Before the emergence of language, the pathogen avoidance module had an inferential signature – but how to communicate this contamination tagging information with others? The functionally-overlapping toxin monitoring system had a clearly visible output: the gape face. Plausibly, the two modules merged such that pathogen monitoring system could co-opt gape face to communicate. We can call this the gape face as signal theory.

My Take on the Theory

The theory I have presented here was developed by Daniel Kelly’s book Yuck! The Nature and Moral Significance of Disgust. The theory strongly complements Mark Schaller’s work on the behavioral immunity system. The overlap between these two researchers will become clear next time, when we turn to the social co-optation of the disgust system.

I personally find the entanglement thesis (the merger of toxin monitoring and pathogen avoidance systems) compelling, given its tremendous explanatory power outline above.

Despite accepting the overall architecture, Kelly’s theory for why the architecture evolved (gape face as signal) strikes me as incomplete.

I also feel like this theory will remain incomplete until we discover how toxin monitoring and parasite avoidance are implemented in dissociable neurobiological structures (i.e., modules).

After the psychological mechanisms are mapped to their physical roots, we could attempt to integrate our knowledge of disgust with other systems:

  • What is the relationship of disgust to the generalized stress response? Stress & the immune systems co-evolved to share the HPA axis, after all.
  • How is disgust implemented in the microbiome-gut-brain axis, which also has links to both the digestive system (enteric nervous system) and the immune system (e.g., leaky gut)?
  • How does the MGB axis differentially produce both disgust and other social phenomena like anxiety?

Open questions are exciting! To me, it suggests a clear research program where we can start integrating our newfound theory of disgust into the broader picture of visceral processes (the hot loop).

Related Resources

  • Kelly (2013). Yuck! The Nature and Moral Significance of Disgust.
  • Fessler & Haley (2006). Guarding the Perimeter: the inside-outside dichotomy in disgust and bodily experience.
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[Excerpt] The Tragedy of Commonsense Morality

Part Of: Demystifying Ethics sequence
Content Summary: 1500 words, 15 min read.

Excerpts are not my writing! This comes from Joshua Greene’s excellent book:

Moral Tribes: Emotion, Reason, and the Gap between Us and Them

The book goes on to present an interesting solution to the below problem. Check it out!

The Tragedy of the Commons

The following parable – entitled tragedy of the commons – originates from Garrett Hardin’s 1968 paper:

A single group of herders shares a common pasture. The commons is large enough to support many animals, but not infinitely many. From time to time, each herder must decide whether to add another animal to her flock. What’s a rational herder to do? By adding an animal to her herd, she receives a substantial benefit when she sells the animal at market. However, the cost of supporting that animal is shared by all who use the commons. Thus, the herder gains a lot, but pays only a little, by adding an additional animal to her herd. Therefore, she is best served by increasing the size of her herd indefinitely, so long as the commons remains available. Of course, every other herder has the same set of incentives. If each herder acts according to her self-interest, the commons will be completely eroded, and there will be nothing left for anyone.

You may recognize the economic structure of this game from the Prisoner’s Dilemma. To win such a game, you must find the magic corner; that is, to accomplish cooperative outcomes despite the temptation of selfishness.

The problem of cooperation is the central problem of social existence. Fortunately, our brains come equipped with the following mechanisms, all of which foster cooperation.

  1. Concern for others. Two prisoners can find the magic corner if they place some value on each other’s payoffs in addition to their own.
    • Faculties: empathy, violence aversion.
  2. Direct reciprocity. Two prisoners can find the magic corner if they know that being uncooperative now will deny the benefits of future cooperation.
    • Faculties: punitive motivation, forgiveness, gratitude
  3. Commitments. Two prisoners can find the magic corner if they are committed to punishing each other’s uncooperative behavior.
    • Faculties: shame, guilt, loyalty.
  4. Reputation. Two prisoners can find the magic corner if they know that being uncooperative now will deny us the benefits of future cooperation with others.
    • Faculties: gossip, embarrassment.
  5. Assortment. Two prisoners can find the magic corner by belonging to a cooperative group, provided that group members can reliably identify one another.
    • Faculties: identity markers, tribalism

We have cooperative brains, it seems, because cooperation provides material benefits, biological resources that enable our genes to make more copies of ourselves. Out of evolutionary dirt grows the flower of human goodness.

The Tragedy of Common Sense Morality

To the east of a deep, dark forest, a tribe of herder raise sheep on a common pasture. Here the rule is simple: each family gets the same number of sheep. Families send representatives to a council of elders, which governs the commons. Over the years, the council has made difficult decisions. One family, for example, took to breeding exceptionally large sheep, thus appropriating more of the commons for itself. After some heated debate, the council put a stop to this. Another family was caught poisoning its neighbors’ sheep. For this the family was severely punished. Some said too severely. Others said not enough. Despite these challenges, the Eastern tribe has survived, and its families have prospered, some more than others.

To the west of the forest is another tribe whose herders also share a common pasture. There, however, the size of a family’s flock is determined by the family’s size. Here, too, there is a council of elders, which has made difficult decisions. One particularly fertile family had twelve children, far more than the rest. Some complained that they were taking  up too much of the commons. A different family fell ill, losing five of their six children in one year. Some thought it was unfair to compound their tragedy by reducing their wealth by more than half. Despite these challenges, the Western tribe has survived, and its families have prospered, some more than others.

To the north of the forest is yet another tribe. Here there is no common pasture. Each family has its own plot of land, surrounded by a fence. These plots vary greatly in size and fertility. This is partly because some Northern herders are wiser and more industrious than others. Many such herders have expanded their lands, using their surpluses to buy land from their less prosperous neighbors. Some Northern herders are less prosperous than others simply because they are unlucky, having lost their flock or their children to disease. Still other herders are exceptionally lucky, possessing large fertile plots of land, not because they are especially industrious but because they inherited them. Here in the North, the council of elders doesn’t do much. They simply ensure that herders keep their promises and respect one another’s property. The vast differences in wealth among Northern families has been the source of much strife. Each year, some Northerners die in winter for want of food and warmth. Despite these challenges, the Northern tribe has survived, and its families have prospered, some more than others.

To the south of the forest is a fourth tribe. They share not only their pasture but their animals, too. Their council of elders is very busy. The elders manage the tribe’s herd, assign people to jobs, and monitor their work. The fruits of this tribe’s labor are shared equally among all its members. This is a source of much strife, as some tribe members are wiser and more industrious than others. The council hears many complaints about lazy workers. Most members, however, work hard. Some are moved to work by community spirit, others by fear of their neighbor’s reproach. Despite these challenges, the Southern tribe has survived. Its families are not, on average, as prosperous as those in the North, but they do well enough, and in the South no one has ever died in winter for want of food or warmth.  

One summer, a great fire burned through the forest, reducing it to ash. Then came heavy rains, and before long the land, once thick with trees, was transformed into an expanse of gently rolling grassy hills, perfect for grazing animals. The nearby tribes rushed in to claim the land. This was a source of much strife. The Southern tribe proclaimed that the new pastures belonged to all people and must be worked in common. They formed a new council to manage the new pastures and invited the other tribes to send representatives. The Northern herders scoffed at this suggestion. While the Southerners were making their big plans, Northern families built houses and stone walls and set their animals to graze. Many Easterners and Westerners did the same, though with less vigor. Some families sent representatives to the new council.

The four tribes fought bitterly, and many lives, both human and animal were lost. Small quarrels turned into bloody feuds, which turned into deadly battles. A Southern sheep slipped into a Northerner’s field. The Northerner demanded a fee to return it. The Southerners refused to pay. The Northerner slaughtered the sheep. The Southerners took three of the Northerner’s sheep and slaughtered them. The Northerners took ten of the Southerner’s sheep and slaughtered them. The Southerners burned down the Northerners farmhouse, killing a child. Ten Northern families marched on the Southerner’s meeting house and set it ablaze, killing dozens of Southerners, including many children. Back and forth they went with violence and vengeance, soaking the green hills with blood.

The tribes of the new pastures are engaged in bitter, often bloody conflict, even though they are all, in their different ways, moral peoples. They fight not because they are fundamentally selfish but because they have incompatible visions of what a moral society should be. These are not mere scholarly disagreements, although their scholars have those, too. Rather, each tribe’s philosophy is woven into its daily life. Each tribe has its own version of moral common sense. The tribes of the new pastures fight not because they are immoral but because they view life on the new pastures from very different moral perspectives. I call this the Tragedy of Commonsense Morality.

Five psychological tendencies tend to exacerbate intertribal conflict:

  1. Naked group selfishness. Human tribes are tribalistic, favoring Us over Them.
  2. Moral disagreement. Tribes have genuine disagreements about how societies should be organized, with different emphases on e.g., the rights of individuals versus the greater good.
  3. Authority question begging. Tribes have distinctive moral commitments, whereby moral authority is vested in local individuals, texts, traditions and deities that other groups don’t recognize as authoritative.
  4. Asymmetry capitalization. Tribes are prone to biased fairness, allowing group-level self-interest to distort their sense of justice
  5. Punitive escalation. The way we process information about social events can cause us to underestimate the harm we cause others, leading to the escalation of conflict.

Morality is nature’s solution to the Tragedy of the Commons, enabling us to put Us ahead of Me. But nature has no ready-made solution to the Tragedy of Commonsense Morality, the problem of enabling Us to get along with Them. And therein lies our problem. If we are to avert the Tragedy of Commonsense Morality, we’re going to have to find our own, unnatural solution: what I’ve called a metamorality, a higher-level moral system that adjudicates among competing tribal moralities, just as a tribe’s morality adjudicates among competing individuals.

Confabulation: saying more than we can know

Part Of: Demystifying Sociality sequence
Content Summary: 1500 words, 15min read

Anosognosia

It is unfortunate to experience illness. It is strange to fail to recognize illness within oneself. Anosognosia is the name for this inability. A few examples:

Example 1. In a letter to his friend Lucilius, Seneca (40 CE) described a woman who obstinately denied her blindness.“….You know that Harpestes, my wife’s fatuous companion, has remained in my home as an inherited burden….This foolish woman has suddenly lost her sight. Incredible as it might appear, what I am going to tell you is true: She does not know she is blind. Therefore, again and again she asks her guardian to take her elsewhere because she claims that my home is dark…..It is difficult to recover from a disease if you do not know to be ill….”. 

Example 2. After a right-hemisphere stroke, she lost movement in her left arm but continuously denied it. When the doctor asked her to move her arm, and she observed it not moving, she claimed that it wasn’t actually her arm, it was her daughter’s. Why was her daughter’s arm attached to her shoulder? The patient claimed her daughter had been there in the bed with her all week. Why was her wedding ring on her daughter’s hand? The patient said her daughter had borrowed it. Where was the patient’s arm? The patient “turned her head and searched in a bemused way over her left shoulder”. 

Spend enough time with these patients, and it becomes clear that their problem is not cognitive dissonance. No, the delusion has a much deeper, subterranean, hold on their mental lives.  These patients freely generate explanations for their illness-related behavior (“I can’t walk around because the house is dark”, “The unmoving arm isn’t mine, it is my daughters”). These explanations are not examples of dishonesty. They are genuine perceptions of a misfiring mind. The word for these honest lies is confabulation.

Confabulation_ Comparing to Dishonesty (1)

If you’re anything like me, you’ll find such epistemic fences a bit unsettling. Is it possible our entire species is entertaining a similar delusion that increases biological fitness? Do we actually have four fingers but are collectively convinced that little fingers exist?

Split Brain Patients

The vertebrate brain has two hemispheres. Some neural functions are bilateral: visual processing occurs in both right and left hemisphere (one per eye). Other functions are unilateral: language processing is usually left-lateralized (with the exceptions tending to be left-handed). The advantages & disadvantages of lateralization of brain function is an active research area.

In neurotypical animals, there exist traverse fibers (commissures) which integrate information between the hemispheres. The corpus callosum is the overwhelmingly dominant bridge between hemispheres:

  • Corpus Callosum: 250 million fibers
  • Anterior commissure: 0.5 million fibers
  • Posterior commissure: 0.5 million fibers
  • Habenula commisure: 0.1 million fibers

Split brain patients are those that have had their corpus callosum severed. These patients tend to exhibit selfhood fracturing: each hemisphere constitutes a largely autonomous entity with its own beliefs and desires.

Present the left hemisphere with a picture of a chicken claw, and the right with a picture of a wintry scene. Now show the patient an array of cards with pictures of objects on them, and ask them to point (with each hand) something related to what they saw. The hand controlled by the left hemisphere points to a chicken, the hand controlled by the right hemisphere points to a snow shovel. So far so good.

But what happens when you ask the patient to explain why they pointed to those objects in particular? The left hemisphere is in control of the verbal apparatus. It knows that it saw a chicken claw, and it knows that it pointed at the picture of the chicken, and that the hand controlled by the other hemisphere pointed at the picture of a shovel. Asked to explain this, it comes up with the explanation that the shovel is for cleaning up after the chicken. While the right hemisphere knows about the snowy scene, it doesn’t control the verbal apparatus and can’t communicate directly with the left hemisphere, so this doesn’t affect the reply. The patient instead confabulates.

What did ”the patient” think was going on? This is a wrong question. Once you know what the left hemisphere believes, what the right hemisphere believes, and how this influences organism behavior, then you know all that there is to know.

Gazzaniga has described this propensity of patients to confabulate reasons for the behavior of the right brain as the left-brain apologist. The left hemisphere functions as an interpreter, a lawyer, a press secretary:: it justifies behavior to make the organism look good. V.S Ramachandran, drawing on observations that right-brain lesions disproportionately produce delusions, claims the existence of a right-brain revolutionary. It is the failure some module in the right hemisphere that causes anosognosia: the left-brain apologist to go unchecked: confabulation exacerbated by delusion.

Confabulation in Neurotypicals

We have so far explored confabulation in patients with brain damage. Do neurotypical, everyday people produce “honest lies”?

We confabulate all the time.. We just don’t realize that we are.

In Telling More Than We Can Know: Verbal Reports on Mental Processes, Nisbett & Wilson (1977) review hundreds of studies, across dozens of disciplines. Their evidence admits a theme: people’s attempts to explain their behavior is almost always unhelpful in identifying the important factors influencing their decisions. Let me briefly review four example findings.

Study 1: Insufficient Justification.

Zimbardo et al (1969) ask participants to accept a series of painful shocks while performing a learning task. Participants were split into two groups:

  • Adequate Justification (“nothing will be learned unless shocks administered again”)
  • Inadequate Justification (“I’m curious to see what happens”)

Who suffers less?

→ The Inadequate Justification group. This group learns much more quickly, and admit lower galvinic skin response (lower “fight or flight”).

Why do they suffer less?

→ These people were given a poor justification for continuing, and yet they continued anyway. To explain their own behavior, they generate intrinsic motivation for continuing. (As an aside, this phenomenon is similar to the overjustification effect).

Do they know that they suffer less?

→ No! Subjective reports of pain were the same across groups.

Study 2: Attribution Effect

Storms & Nisbett (1970) ask insomnia-suffering participants to sleep under observation. Participants were split into two groups:

  • Arousal Attribution: placebo given, claimed to cause restlessness, alertness
  • Control: no placebo administered

Who falls asleep more quickly?

→ Arousal Attribution group (28% faster).

Why do they fall asleep more quickly?

→ Attribution of restlessness to placebo, rather than cognitive factors.

Do they know why they fall asleep more quickly?

→ No! More than 80% of patients would not attribute sleep improvement to pill, even after the experiment being explained to them.

Study 3: Counterattitudinal Advocacy

Bem & McConnell (1970) ask participants for their view on a political topic. Then ask they write an essay against their own view. Participants were split into two groups:

  • Coercion: bribed to write the essay
  • Freedom: led to believe they had a choice

Who changes their position after writing the essay?

→ Freedom group.

Why do they change?

→ Difficult to explain writing that essay, unless they wanted to.

Do they know that they changed their position?

→ No! In contrast to the Coercion group which had accurate memories, those whose opinions had changed failed to remember their previous position.

Study 4: Choice Blindness

Johannson et al. (2005) ask participants to evaluate which of two female faces was more attractive. Researchers then hand subjects the face they had chosen, asking them to explain the motives behind their choice. Participants were split into two groups:

  • Switch: used a sleight-of-hand trick to switch the photos, showing viewers the face they had not chosen.
  • Control: show the face they had chosen

Does the Switch group notice the change?

→ Most don’t. ⅔ of participants believe they had chosen the other face.

Did those who didn’t notice explain of their (non-)choice?

→ Without missing a step. They happily explained why they preferred the face they had actually rejected, inventing reasons like “I like her smile” even though they had actually chosen the solemn-faced picture.

Putting It All Together

Confabulation is “honest lying”: communicating an untruth, while earnestly believing in its veracity.

  • Anosognosia patients cannot admit that they are paralyzed. When asked to explain their inability to move, they confabulate answers.
  • Split brain patients similarly confabulate explanations for the behavior of the non-linguistic right hemisphere.
  • Confabulation is not merely a medical curiosity. Confabulation is everywhere: most self-reports are utterly useless. Some evidence includes:
    1. Insufficient Justification: people didn’t notice when they were suffering less
    2. Attribution Effect: people failed to understand the reason why they slept better
    3. Counterattitudinal Advocacy: after people change their minds, they fail to remember they ever thought differently
    4. Choice Blindness: once tricked into thinking they chose something different, people are happy to explain their reasons.

Confabulation_ Evidence Overview

Why do human beings confabulate so often? How can we be such utter strangers to ourselves?  We shall explore these questions next time. Until then!

The Construction of Body Status

Part Of: Neuroeconomics sequence
Content Summary: 800 words, 8 min read

Connection To Philosophy of Well-being

What is well-being?

Philosophers have put forward three theories.

  • Hedonic Theory. Well-being is experiencing pleasure.
  • Desire Fulfillment Theory. Well-being is achieving your goals.
  • Objective List Theory. Well-being is living an objectively good life.

In this post, we ask “does the brain have any incentive to compute biological measures of well-being? If so, what would this data structure be used for?”

Well-being is Body Status

Everyone agrees that the following are true about well-being:

  1. Well-being is sensitive to variables of body status. Instantaneous well-being is less if an animal is in pain, other things being equal.
  2. Well-being responds to many divergent factors (e.g., both pain and hunger reduce instantaneous well-being).

But there is only one biological apparatus that satisfies these properties:

Proposition 1. Well-being is body status, constructed by regulatory processes.

In 1925, Walter Cannon formulated homeostasis, which posits the body striving to maintain internal variables essential for life. For example, the body measures its own body temperature. If it is too hot or cold, a negative feedback process will initiate actions to bring the variable back into its optimal value.

homeostasis (2)

The body tracks many more variables besides body temperature. These variables together constitute a representation I will call body status:

Wellbeing Biology- Healthy Organism Body Status (2)

Body status representations play a key role in the biological construction of personal identity and subjectivity. We will return to this topic at another time.

Desire from Body Status

Markov Decision Process (MDPs) are a lens through which we can interpret behavior. An MDP contains states, actions, and a reward signal. The organism selects a policy \pi such that the states encountered maximize the reward signal.

mdp basics

Within the brain, the basal ganglia implements two data structures which together generate motivation:

  • A policy 𝝅 which maps states to actions, S → A.
  • A value function V(s) which represents expected reward.

Reinforcement learning theory is silent on the biological substrate of the reward signal. But to us, the solution is clear:

Proposition 2.  Reward is derived from the body status representation.

Body Status- Construction of Reward Signal (1)

This is one mechanism by which low body temperature is corrected. Body status deviations elicit a reward signal that prompt “cold” motor desires (e.g., shivering). In contrast, notice that “hot” visceral desires (e.g., blood vessel constriction) are constructed directly, not implemented by the basal ganglia.

Hedonics from Body Status

Hedonics describe the experience of pleasure and pain. Hedonics usually correlates with desire: we approach things that are pleasant, and avoid things that are unpleasant.

Yet drug addicts often reach the point where drug consumption is unpleasant, yet they pursue a fix regardless. Wanting and liking are dissociable. Why? Because they are implemented by different neurochemical systems (phasic dopamine and opioids, respectively).

Body status is not only used to behaviorally motivate. In my view, it also tags perceptual data with information about its visceral relevance.  This includes the two primary affective dimensions:

  • Object salience (“does this merit attention, further computation”)
  • Object hedonics (“is this safe to approach”)

Body Status- Tagging for Visceral Relevance (1)

So we have arrived at our next thesis:

Proposition 3. Hedonics are derived from the body status representation.

Philosophers debate whether well-being is best attributed to pleasure/pain or desire. But body status is used to construct both of these phenomena. This gives us reason to believe that the philosophical theories of hedonism and desire fulfillment can be unified.

The Socialification of Body Status

Across the course of natural history, certain animals have become increasingly social, able to interact more meaningfully with their conspecifics.

Three important social adaptations were:

  • In mammals, social status. Animals track their standing in the group.
  • In primates, social inclusion. Group living made possible by e.g., exchange of favors.
  • In hominids, social reputation. An prosocial alternative to power, independent of the dominance hierarchy.

How might a biological organism introduce these new behavioral repertoires? A simple way to do it might be to extend body status to incorporate social variables of interest:

body status socialification

Proposition 4. Body status was extended to support novel social behaviors.

This proposition lends a biological perspective why social ostracization is so painful, and elicits physiological distress directly comparable to e.g., evading predation.

This socialification hypothesis is more speculative than my other three propositions. How might we go about evaluating whether it is true?

Recall that body status is represented by an overlapping set of neurochemical networks, whose main connecting hub is the hypothalamus. If Proposition 4 is true, we would expect to find new chemical systems uniquely responsive to these proposed dimensions.

I suspect these connections will be established rather quickly. We already possess several extremely suggestive lines of evidence. See, for example, Hennessy et al (2014). Sociality and sickness: have cytokines evolved to serve social functions beyond times of pathogen exposure?

Takeaways

Today, I presented the following ideas:

  • Proposition 1. Well-being is body status, constructed by regulatory processes.
  • Proposition 2. Desire is derived from the body status representation.
  • Proposition 3. Hedonics are derived from the body status representation.
  • Proposition 4. Body status was extended to support novel social behaviors.

Until next time.

Counting: The Fourfold Way

Part Of: Statistics, Algebra sequences
Content Summary: 1100 words, 11 min read

The Fundamental Principle of Counting

We often care to count the number of possible outcomes for multiple events.

Example 1. Consider purchasing a lunch with the following components:

  • Burger b \in \{ Chicken, Beef \}
  • Side s \in \{ Fries, Chips \}
  • Drink d \in \{ Fanta, Coke, Sprite \}

How many lunch outcomes are possible?

Three approaches to counting suggest themselves. We might make a list. But this process can be error prone. Other representations are more systematic: we can build a tree, or imagine a (hyper)-volume. Each strategy converges on the same answer: 12 possible lunches.

Permutation_ Trees of Events (1)

Can we generalize? Yes, with the help of the fundamental principle of counting (aka the rule of multiplication). For any event A with a possible outcomes, and another event B with b possible outcomes, the number of possible outcomes for composite event A \cup B is a*b

How does counting work for a repeating event? For an event with n possibilities occurs k times, there are k^n possible outcomes.

Example 2. How many numbers can be represented by a byte (8 bits)?

Each bit has two possible assignments: zero or one. For eight such “bit events”, we have 2^8 = 256 possible outcomes.

Permutations

Example 3. A trifecta bet guesses which horse will place first, which second, and which third.  How many such bets are possible in a 9-horse race?

Each medal has nine possible assignments. For three such “medal events”, we have 9^3 = 729 possible outcomes.

This answer is completely wrong. To understand why, consider the lottery machine:

powerball

  • In Example 2, a single value (e.g., 0) can freely be assigned to multiple bits. Every time you draw a bit from the “possibility machine”, it is replaced when the next bit is drawn. Sampling with replacement means that each event is exactly the same.
  • In Example 3, a single horse (e.g., Secretariat) cannot be assigned multiple medals. Every time you draw a horse from the “possibility machine”, it cannot be drawn for subsequent events. Sampling without replacement means that each event has diminishing numbers of possibilities.

Definition 4. A permutation is a list of outcomes drawn without replacement.

For the trifecta bet, how many permutations exist? Well, 9 different horses that earn the gold. Given that one horse won the gold, 8 different horses that can earn the silver. Then there are 7 different horses that can earn bronze. Thus, there are 9 \times 8 \times 7 = 504 possible trifecta bets.

Permutation_ 9 perm 3

Similar to how exponentiation is defined as repeated multiplication, a factorial is defined as slowly-decrementing multiplication.

9! = 9 \times 8 \times 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1

But we only want 9 \times 8 \times 7. How can we get rid of the other terms? By division, of course!

9 \times 8 \times 7 = \dfrac{9 \times 8 \times 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}{6 \times 5 \times 4 \times 3 \times 2 \times 1} = \dfrac{9!}{6!}

Why did we use the number 6? Because if three of our nine horses place, six do not place. So a more general way to write this equation,

\dfrac{9!}{9-3!}

More generally, if you have n items and want to find the number of ways k items can be ordered:

Equation 5: Permutation. P(n, k) = \dfrac{n!}{(n-k)!}

Combinations

In contrast to permutations, for combinations, order doesn’t matter. A permutation is a list, a combination is a set.

A boxed trifecta bet requires correctly which three horses will place first, second and third (order doesn’t matter). A trifecta bet selects a permutations; a boxed trifecta bet selects a combination.

Imagine only four horses in the race. That’s P(4,3) = \dfrac{4!}{4-3!} = 24 possible trifecta bets. But how many boxed trifecta bets are possible?

Combinations treat duplicates as a single entry. For example, abc and acb are equivalent for a boxed trifecta bet. We can identify four groups, with six equivalent permutations each:

Permutation_ 4 choose 3

In general, how many winner duplicates exist? How many ways can we shuffle k winners? Well, if you have k winners and are wondering how many permutations exist for that entire set… that’s P(k,k)!

Equation 6: Combination. C(n, k) = \dfrac{P(n,k)}{P(k,k)} = \dfrac{P(n,k)}{k!} = \dfrac{n!}{(n-k)! k!}

For an example of combinations used to solve a real problem, I recommend this post.

The Fourth Way: Stars and Bars

Example 7. You have k=3 cookies a, b, c, d to give to n=4 kids. How many possible ways are there to do so?

In the case of medals and horses, we claimed four solutions: \{ a, b, c\}\{ a, b, d\}\{ a, c, d\}, and \{ b, c, d\}. But there is an important difference: horse-less medals are impossible, but cookie-less children are not! So we need to account for situations like \{ a, a, a\}, with one child getting all of the cookies.

We can use the traditional bins-as-containers metaphor to visualize outcomes (top row). Or we can instead visualize bin boundaries (bottom row). This visualization strategy is called stars and bars.

Combinatorics_ Stars and Bars (2)

How many kid-cookie outcomes are possible? The answer becomes apparent only if we use stars and bars  (bottom row). Every possible shuffling of the stars in those squares produces a valid event. That is, \binom{6}{3}.

How many objects are possible in general? There are n stars (kids). Since bars represent bin boundaries, there are n-1 bars. Thus:

Equation 8: Multi-Combination. C(n, k) = \binom{n+(k-1)}{k}

The Fourfold Way

Every example we have seen differentiates possibilities and outcomes. We will use the metaphor of balls for outcomes (something concrete) and bins for possibilities (something to “clothe” outcomes).

Combinatorics_ Possibilities vs Outcomes

Equation 9. An event is a function that maps outcomes to possibilities:

Event : Outcomes \rightarrow Possibilities

Combinatorics_ Events as Functions (2)

This function can be compactly represented as bbd.

Functions require every element of the domain to map to the codomain. Event functions require no unrealized outcomes. That is: every outcomes manifests a possibility. Every ball is given a bin.

We saw previously that combinations and permutations don’t allow events like aab and ccc. A single horse cannot win multiple medals. Multiply-realized possibilities are not allowed.

Recall the definitions of injective, surjective and bijective functions. This requirement is the injective property. Sampling without replacement is the same thing as injectivity.

Tuple, permutation, combination, and multi-combination. This is the fourfold way.  The Way can be made more general by counting situations where the possibilities are unlabeled, and the event function meets the surjection property. But for details on the more complete twelvefold way, I recommend this post.

Combinatorics_ Fourfold Way

Towards a Rosetta Stone

Now, consider all possible functions for 4 bins and 3 balls:

Combinatorics_ Rosetta Stone (4, 3)

What do the equations above have to do with this shape? Well, each way of counting corresponds with a different subset of this broader shape:

Combinatorics_ Shape of The Way (1)

I leave it to the interested reader to ponder, how such a jagged shape can be represented by these four relatively clean formulae.

Until next time.

Related Resources

https://www.ece.utah.edu/eceCTools/Probability/Combinatorics/ProbCombEx15.pdf

https://wizardofodds.com/games/poker/

http://www.math.hawaii.edu/~ramsey/Probability/PokerHands.html

Jesus, disciple of John

Why do the Gospels care about John?

In the 20s CE, at least two prophets were active in the Israelite highlands: John the Baptist and Jesus of Nazareth. Both were killed on political grounds. Jesus left behind disciples that remained loyal to him in some sense. So did John. In fact, these two religious groups interacted (vied for influence?) after the deaths of their leaders.

Ultimately, John’s religious group died out; Jesus’ following did not. With the exception of Josephus and a few other secular sources, the Christian gospels are our best source of information of the religious climate of this time period.

These Christian gospels spend an astonishing amount of time describing John: both his independent ministry, and his relationship with Jesus. John’s message that a powerful Son of Man will judge the world, is interpreted by Christians as referring to Jesus.

Why should the gospels lavish John with such attention and theological import? Two hypotheses suggest themselves,

  1. The early Christians shared a broader Jewish respect for John’s ministry, and that reverence led to the attention & theological significance.
  2. The early Christians crafted the gospels partially in effort to convert John’s disciples.

As we shall see, neither of these hypotheses are adequate. Instead, we shall see evidence suggesting that Jesus began his ministry as a disciple of John.

On Jesus’ Baptism

The gospels record that John baptized Jesus. This event is prima facie embarrassing for two reasons:

  1. Implications of imperfection. John’s baptism was clearly and consistently described as “for the forgiveness of sins”.
  2. Implications of subordination.  This is the reason Matthew has the Baptist say “I need to be baptized by you, yet you come to me?”

Mark and Matthew combat with these implications by describing a theophany where God calls Jesus his Son. In contrast, Luke makes the Baptist a relative of Jesus, and has John imprisoned before Jesus’ baptism. We are never explicitly told who baptizes Jesus. And in the fourth gospel, John the Baptist is not the Baptist, the title is never used on him. He even denies that he is Elijah, even though in Matthew, Jesus flatly affirms that he is.

This incredible diversity of interpretations is due to a simple fact. At the beginning of Jesus’ ministry stands an independent Baptist, a Jewish prophet who won great popularity and reverence before and apart from Jesus, who also won the reverence and submission of Jesus to his baptism of repentance for the forgiveness of sins, and who left behind a religious group that continued to exist apart from Christianity.

The Baptist constituted a stone of stumbling right at the beginning of the story of Jesus, a stone too well known to be ignored or denied, a stone that each evangelist had to come to terms with as best he could. The embarrassment of the evangelists is illustrated by the diverse, not to say contradictory ways in which they try to bend the independent Baptist to a dependent position within the story of Jesus.

A Common Vision

The gospels record that Jesus was baptized by this prophet. But why would he go? Since nobody compelled him, he must have gone to John because he agreed with John’s message.

There were lots of other groups vying for Jewish attention. Jesus did not join the Pharisees, who emphasized scrupulous observance of the Torah. He did not align himself with the Sadducees, who focused on the worship of God through the Temple cult. Nor did he associate with the Essenes, who formed monastic communities to maintain their own ritual purity. Nor did he subscribe to the teaching of the “fourth philosophy”, which advocated a violent rejection of Roman domination.

No, Jesus associated with an ascetic prophet who proclaimed an imminent end of history. As we will see later, this fact will shed light on the ministry of the historical Jesus.

A Common Practice

Was Jesus’ baptism a singular event? Did he spend much time with John? Was he admitted into John’s inner circle?

Jesus’ first disciples were John’s disciples. If some disciples of the Baptist came to transfer their allegiance to him while they were still in the company of the Baptist, that suggests that Jesus had stayed in the Baptist’s orbit long enough for some of the latter’s disciples to come to know him and be impressed by him.

The fourth gospel admits that Jesus’ ministry included baptism. In fact, not ten sentences later, and that claim is baldy contradicted. However, several pieces of evidence suggest this is the (rather clumsy) work of a Johannine redactor.

Jesus practicing baptism is further reinforced by Mark 11:27-30: “The chief priests asked Jesus, “Who gave You this authority to do these things? Jesus replied, “One question, then I will tell you. Was John’s baptism from heaven or from men?”

The Sadducees were keen to admit John’s religious authority, and deny Jesus’. So why would Jesus invoke John’s baptism? A likely explanation is that it was an area of ministry overlap: the Sadducees couldn’t well admit John’s baptism was divine, yet criticize Jesus’ ministry which included that very baptism.

Jesus as Disciple

A picture is slowly emerging. Jesus began his public life as one of John’s disciples. This is the best explanation for his a) being baptized by John, b) taking John’s disciples, c) practicing John’s baptism. He slowly differentiated himself with the following teachings:

  • Non-asceticism. John was renowned for his minimal lifestyle. Jesus was no stranger to parties, so to speak.
  • Miraculous works. John’s ministry did not feature miracles. Jesus’ did, and he used this to illustrate his end-times message.

Yet despite these divergences, Jesus and John operated largely complementary ministries. Consider Matthew 11:16-19

To what should I compare this generation? It’s like children who call out to each other: “We played the flute for you, but you didn’t dance; we sang a lament, but you didn’t mourn!”

For John did not come eating or drinking, and they say, ‘He has a demon!’ Jesus came eating and drinking, and they say, ‘Look, a glutton and a drunkard, a friend of tax collectors and sinners!’

Yet wisdom is vindicated by her children.

This passage is remarkable because it places John and Jesus’ ministry side by side. Absent are theological claims of Jesus’ superiority.  To be sure, John’s asceticism and Jesus’ non-asceticism are contrasted. Yet John (lamenter) and Jesus (flute player) are both children of wisdom.

Jesus after John

What was the relationship like between John and Jesus? Did they always function collaboratively, or competitively?

The details of this relationship are largely lost to history. Some evidence of tension can be inferred in how frequently Jesus was asked to clarify his relationship to John.

One of our most compelling clues, however, lies in the moving plea from Jesus to his former rabbi:

When John heard in prison what the Messiah was doing, he sent a message by his disciples and asked Him, “Are You the One who is to come, or should we expect someone else?” Jesus replied to them, “Go and report to John what you hear and see: the blind see, the lame walk, those with skin diseases are healed, the deaf hear, the dead are raised, and the poor are told the good news. And if anyone is not offended because of Me, he is blessed.

Absent are the polemics so typical of Jesus’ sayings.  This beautitude has an audience of one. This delicate appeal to his former rabbi: “please do not be offended because of [my origin]”. And yet here, tellingly, the conversation stops. We are not told John’s reply. The relationship is left ambiguous, as John heads for his execution by Herod Antipas.

After the execution of the Baptist, Jesus’ ministry developed by itself. And yet, as we will see, Jesus never fully emerges from the shadow of John. Their common ministry and message pervades the remaining years of Jesus’ ministry.

Polytheistic Roots of Israelite Religion

Part Of: Demystifying Religion sequence
Followup To: Yahweh and the Levites
Content Summary: 2000 words, 10min read.

Introduction

Is the Hebrew Bible monotheistic?  

We might be tempted to say yes after reading Isaiah 44:6 “I am the first and I am the last; besides me there is no God”.

But the situation is more complicated. The Hebrew Bible is also replete with polytheism. A few examples:

  • “Do you not possess that which Chemosh, your god, has given you? So shall we possess what Yahweh has given us.” Judges 11:24
  • “Who is like Yahweh among the gods?” Exodus 15:11
  • “The people of Judah have as many gods as they have towns.” Jeremiah 11:13

We also see middle ground staked out between these two positions. For example, the original audience of the book of Deuteronomy is often exhorted not to follow after other gods, without it ever being asserted that these gods did not exist or were not real. This is known as monolatrism (“single worship”).

Which belief came first?

Last time, we showed how Yahweh was originally a god of metallurgy in northwest Saudi Arabia. Today, we will work with the framework that Yahweh was introduced to Israel in a five-stage process:

  1. Traditional Polytheism. The earliest Israelites worshipped creator god El, his wife Asherah, and his sons e.g., Baal.
  2. Incorporation. Yahweh was incorporated as a 2nd tier god in El’s pantheon.
  3. Elevation. Yahweh and El are identified as the same deity.
  4. Monolatrism. A new Yahweh-only movement emerges, and the gods of the second tier are denied.
  5. Monotheism. Gods of other nations are denied, Yahweh’s power is deemed universal in scope.

Why did Yahweh worship progress along this trajectory? As we shall explore next time, as with the theocracies of surrounding nations, changes in the religious landscape have strong, robust correlates in the sociopolitical life.

Today I’d like to focus on a different, simpler topic. We shall turn to archaeology and cultural anthropology to explore expressions of polytheism within the Hebrew Bible. Many of my readers already know that the text acknowledges (polemicizes against) polytheistic practices. Less well-known are examples of celebration (bald assertions of polytheistic beliefs) and assimilation (Yahweh “adopts” the roles and characteristics of rival deities). 

Monotheism_ Five Stages (2)

 

Let’s review the deities in El’s pantheon, and their appearance in the Hebrew Bible.

A Disclaimer

For many modern readers, polytheism is a term loaded with negative connotation. Partisans use it as a weapon. Attackers point to continuities between Israelite religion & polytheism, and defenders point to instances where Israelite rhetoric polemicizes against polytheism. But all ideological innovations have both features.

More to the point, those who spend time interacting with polytheism understands how earnestly it grapples with the same aspects of the human condition as other strands of religious expression. Polytheism must be encountered on its own terms. To weaponize is to misunderstand.

The important thing to bear in mind in the following, is that underneath the images and icons of religious expression lie a particular group of people, responding to social and political pressures in thoroughly understandable ways. My experience has been, the more time you spend in someone else’s culture, the easier it becomes to empathize with their plight.

El

Israelite Polytheism_ El

At some point in its history, El was identified with Yahweh as the same god.

This equation is expressed clearly in Exodus 6:2-3. “And God said to Moses, “I am Yahweh. I appeared to the patriarchs as El, but by my name Yahweh I did not make myself known to them.” Other Biblical material asserts this equation. Joshua 22:22 states “the god of gods is Yahweh”. Judges 9:46 refers to “El of the covenant”.

The Yahweh-alone movement vigorously condemn prominent Canaanite gods… except El. There are zero condemnations of El in the Hebrew Bible. This makes sense if Yahweh was ultimately identified with this Canaanite creator-god. What’s more, archaeological evidence suggests that the Yahweh religious centers in Shiloh and Bethel were originally a place of El worship.

El and Yahweh are attributed same characteristics. El is depicted as a wise old man with a beard eg “You are great, O El, and your hoary beard instructs you”. Yahweh is described in the same terms (Daniel 7:9, Job 36:26, Habakkuk 3:6). Like “Kind El, the Compassionate”, Yahweh is a “merciful and gracious god”. The description of Yahweh’s dwelling place as a tent (Psalms 15:1, 27:6, 91:10) recalls the tent of El in the Canaanite narrative of Elkunirsa. Finally, both Yahweh and El are said to dwell amidst cosmic waters (Isaiah 33:20-22, Ezekiel 47:1-12, Zechariah 14:8).

Just as Zeus had a council, or assembly, of other gods, so too does Yahweh. The Hebrew Bible is overflowing with references to Yahweh’s (El’s) assembly. See for example Psalm 89:6-8, Zechariah 14:5, 1 Kings 22:19, Isaiah 6:1-8, and Jeremiah 23:18,22.

Baal

Israelite Polytheism_ Baal

Worship of Baal can be dated back to the foundation of Israelite societies. This can be seen in onamatology, the study of proper names. Names in the Ancient Near East tend to have a theophoric component: usually a suffix that honors a deity. Yahwistic names include Josiah, Jehu (note the “J” sound); Baal-oriented names include e.g., “Zerubabbel”. In addition to hundreds of icons devoted to Baal worship, we also see Ba’al theophoric names as common in the Levant in this time period.

Yahwistic prophets of this period reserve the most vitriol for Baal worship. Why? Because the Omride dynasty (including King Ahab & Jezebel) erected a temple to Ba’al. While the cult of Yahweh continued in the northern kingdom, Baal was perhaps elevated as the patron god of the northern monarchy, thus creating some sort of theopolitical unity between the kingdom of the north and the city of Tyre.

Indeed, there is some evidence that the cult of Baal and Yahweh got conflated in the north. Hosea 2:16-24 suggest that some northern Israelites did not distinguish between Yahweh and Baal. The religious sanctuaries in the Israelite cities of Dan and Bethel centered around golden calves; this iconography strongly parallels that of Baal. Finally, the redundancy in 1 Kings 16:32 was almost certainly a scribe glossing over the original text, “altar for Baal in temple of Yahweh”.

To induce the Israelites to stop worshipping Baal, the imagery of Baal was adopted by the Yahweh cult. The Baal Cycle, ancient mythology on the scale of the Epic of Gilgameth, has four literary themes for the storm god. Here are those themes, along with the Biblical text which mirrors them.

  1. The march of the divine warrior (Psalm 104:3 “He makes the clouds his chariot, and travels along on the wings of the wind”)
  2. The convulsions of nature as the divine warrior manifests his power (Judges 5:5, Hab 3:10)
  3. The return of the divine warrior to his holy mountain to assume divine kingship (Isaiah 31:4)
  4. The utterance of the divine warrior’s voice from his palace provides rains that fertilize the earth (Jeremiah 10:13)

Yahweh is also depicted as defeating Baal’s classic enemies:

  • Baal/Yahweh defeats a seven headed dragon, Leviathan, and River (CAT 5.1, Psalm 74:13-15).
  • Baal/Yahweh defeats Sea (KTU 1.14, Psalm 89:10).
  • Baal/Yahweh defeats Death/Mot (KTU 1.4 VIII-1.6, Isaiah 25:8).

Asherah

Israelite Polytheism_ Asherah

El’s wife was named Asherah. When Yahweh was identified with El, did he also inherit his wife? In the blessings of Joseph, Genesis 49:25 contains language specific to the Asherah cult “blessings from Breast-and-Womb”. The Bible further admits that the Israelites frequently worshipped a “Queen of Heaven” (Jeremiah 7:18, 44:17-25). Indeed, 2 Kings 21:7 tells us that worship of Asherah happened within the Temple itself. Finally, archaeology has uncovered several icons with the inscription “Yahweh and his Asherah”. This evidence cumulatively suggests that, in early forms of Israelite religion Yahweh was believed to have a wife.

Israelite polytheism_ Yahweh and his Asherah

The push towards monolatrism led to the eviction of the Asherah cult, whose memory may be preserved in Zechariah 5:5-11. But this eviction created a deficit of femininity to Israelite religious expression. To compensate, the Biblical writers began attributing feminine attributes to Yahweh (Isaiah 49:15, 46:3, 44:2,24, 42:14). Asherah-like characteristics also appear in the goddess of Wisdom in Proverbs 8.

Astral-ification

There is extensive evidence for worship of an astral deity (sun god) in Jerusalem.  And Jerusalem is presumably the site that Yahweh was identifed with El. Since the Ugaritic texts hint that El’s family was astral in character, it is not unthinkable that Yahweh was viewed similarly.

  • Proper names. A certain number of proper names are constructed from the root ‘-w-r (“shine, gleam, light”). These include Uriyyah (“Yhwh is my light”) the name of one of David’s generals, Neriyahu “Yhwh is my lamp”, Yizrayah “Yhwh gleams”, minister of Hezekiah, and dozens more.
  • Archaeology. Many pieces of material evidence, including many seals found in Jerusalem with image of the sun, or the sun god in the form of a wing bed scarab.
  • Biblical affirmations. Job 38:6-7 may attest to Israelite recognition of astral deities “Who sets its cornerstone when the morning stars sang together, and all the divine beings shouted for joy?” Similarly Judges 5:20 features conflict in the astral plane “the stars fought in the heavens”.
  • Biblical acknowledgements. Ezekiel 8:16 has Israelites worshipping sun gods. So does 2 Kings 23:5,10-11 and Zephaniah 1:4-5.
  • Biblical Incorporation. The story of Sodom and Gomorrah reflects astral themes, where the divine punishment is meted out at the moment when the sun rises. It is even possible that the two messengers and the deity in the story represent the sun god and his two acolytes. Psalm 19:4-6 and Psalm 84:11 also shows Yahweh taking on astral qualities.

Other Deities

The Ugaritic texts mention hundreds of Canaanite gods. The Bible only criticizes two of them: Ba’al and Asherah. What gives?

The Biblical authors conflates Asherah and Astarte, and conflates multiple male god as “the Baals”.  Despite this, there is only evidence of ~10 gods worshipped in early Israel. This is also true amongst Israel’s neighbors. It appears that the religious landscape of Iron Age Canaan was simply less diverse than Bronze Age Ugarit.

Do we see evidence for these gods in the Bible, despite their not being named in that text?

Anat. Known for her savagery, Anat worship involves a celebration of gore. “Knee-deep she gleans in warrior blood, neck-deep in the gore of soldiers, until she [Anat] is sated with fighting.”  While no evidence of Anat-worship exists in ancient Israel, these divine themes have strong parallels in the Biblical text. The Bible describes heaps of copses, drinking blood, devouring flesh, and swords dripping with viscera.

Astarte. In the Bible, the Name of Yahweh is described in personal terms. The divine name acts as a warrior (Isaiah 30:27) and possesses martial qualities such as radiance and strength (Psalm 29:1-2). The warrior goddess Astarte bears the title “name of Baal”. This designation of Astarte and her martial character and special relationship to the god Baal approximate the martial character of the name, and its special relationship to Yahweh as warrior god. Further evidence for this hypothesis has been adduced from the Elephantine papyri

Similar lines of argument can be made for entities like Light and Truth of Psalm 43:3.

Angels. The lowest tier of the Israelite pantheon also went through alterations. As the Ugaritic texts show, the lowest tier involved a number of deities who served in menial capacities. A common task for such gods was to act as messenger, the literal meaning of the English word “angel”. Certainly angels are not regarded in later traditions as gods. But they were in early traditions.

Takeaways

This post provides evidence for a simple point. Polytheistic expression (not just condemnation!) occurs in the Hebrew Bible.

These expressions are best explained by the Yahweh cult shifting away from its traditional pagan roots, and towards a monolatrist (worship one god) and later monotheist (acknowledge one god) understandings.

As we will see next time, the reasons why Yahweh worship proceeded in this interesting (but not original) trajectory, are fairly easy to understand.