Temporal lobe epilepsy

From Wikipedia, the free encyclopedia

Temporal lobe epilepsy (TLE)
Lobes of the brain. Temporal lobe in green
Classification and external resources
Specialty	Psychiatry, Neurology
ICD-10	G40.1-G40.2
ICD-9-CM	345.4
DiseasesDB	29433
MedlinePlus	001399
eMedicine	neuro/365
Patient UK	Temporal lobe epilepsy
MeSH	D004833

Temporal lobe epilepsy (TLE) is a chronic disorder of the nervous system characterized by recurrent, unprovoked focal seizures that originate in the temporal lobe of the brain and last about one or two minutes. TLE is the most common form of epilepsy with focal seizures. A focal seizure in the temporal lobe may spread to other areas in the brain when it may become a focal to bilateral seizure.

TLE is usually diagnosed in childhood or adolescence. TLE is diagnosed by taking a medical history, blood tests, and brain imaging. It can have a number of causes such as head injury, stroke, brain infections, structural lesions in the brain, or brain tumors, or it can be of unknown onset. The first line of treatment is through anticonvulsants. Surgery may be an option, especially when there is an observable abnormality in the brain. Another treatment option is electrical stimulation of the brain through an implanted device called the vagus nerve stimulator (VNS).^[1]

Types

Over forty types of epilepsy are recognized and these are divided into two main groups: focal seizures and generalized seizures.^[2] Focal seizures account for approximately sixty percent of all adult cases.^[3] Temporal lobe epilepsy (TLE) is the single most common form of focal seizure.^[4]

The International League Against Epilepsy (ILAE) recognizes two main types of temporal lobe epilepsy: mesial temporal lobe epilepsy (MTLE), arising in the hippocampus, the parahippocampal gyrus and the amygdala which are located in the inner (medial) aspect of the temporal lobe and lateral temporal lobe epilepsy (LTLE), the rarer type, arising in the neocortex at the outer (lateral) surface of the temporal lobe.^[3] The seizures of LTLE are characterized by auditory or visual features. Autosomal dominant lateral temporal lobe epilepsy (ADLTLE) is a rare hereditary condition, often associated with mutations in the LGI1 gene.^[5]

Signs and symptoms

When a seizure begins in the temporal lobe, its effects depend on the precise location of its point of origin, its locus. In 1981, the ILAE recognized three types of seizures occurring in temporal lobe epilepsy. The classification was based on EEG findings.^[6] However as of 2017 the general classification of seizures has been revised.^[7] The newer classification uses three key features: where the seizures begin, the level of awareness during a seizure, and other features.^[7]

Focal seizures

MRI Location amygdala

Focal seizures in the temporal lobe involve small areas of the lobe such as the amygdala and hippocampus.

The newer classification gives two types of focal onset seizures, as focal aware and focal impaired awareness.^[2]

Focal aware seizures

Focal aware means that the level of consciousness is not altered during the seizure.^[2] In temporal lobe epilepsy, a focal seizure usually causes abnormal sensations only.
These may be:

• Sensations such as déjà vu (a feeling of familiarity), jamais vu (a feeling of unfamiliarity)
• Amnesia; or a single memory or set of memories
• A sudden sense of unprovoked fear and anxiety
• Nausea
• Auditory, visual, olfactory, gustatory, or tactile hallucinations.
• Visual distortions such as macropsia and micropsia
• Dissociation or derealisation
• Synesthesia (stimulation of one sense experienced in a second sense) may transpire.^[8]
• Dysphoric or euphoric feelings, fear, anger, and other emotions may also occur. Often, the patient cannot describe the sensations.^[9]

Olfactory hallucinations often seem indescribable to patients beyond "pleasant" or "unpleasant".^[10]

Focal aware seizures are often called "auras" when they serve as a warning sign of a subsequent seizure. Regardless an aura is actually a seizure itself, and such a focal seizure may or may not progress to a focal impaired awareness seizure.^[11] People who only experience focal aware seizures may not recognize what they are, nor seek medical care.

Focal impaired awareness seizures

Focal impaired awareness seizures are seizures which impair consciousness to some extent:^[2] they alter the person's ability to interact normally with their environment. They usually begin with a focal aware seizure, then spread to a larger portion of the temporal lobe, resulting in impaired consciousness. They may include autonomic and psychic features present in focal aware seizures.

Signs may include:^[12]

• Motionless staring
• Automatic movements of the hands or mouth
• Confusion and disorientation
• Altered ability to respond to others, unusual speech
• Transient aphasia (losing ability to speak, read, or comprehend spoken word)

These seizures tend to have a warning or aura before they occur, and when they occur they generally tend to last only 1–2 minutes. It is not uncommon for an individual to be tired or confused for up to 15 minutes after a seizure has occurred, although postictal confusion can last for hours or even days. Though they may not seem harmful, due to the fact that the individual does not normally seize, they can be extremely harmful if the individual is left alone around dangerous objects. For example, if a person with complex partial seizures is driving alone, this can cause them to run into the ditch, or worse, cause an accident involving multiple people. With this type, some people do not even realize they are having a seizure and most of the time their memory from right before or after the seizure is wiped. First-aid is only required if there has been an injury or if this is the first time a person has had a seizure.

Focal to bilateral seizures

Seizures which begin in the temporal lobe, and then spread to involve both sides of the brain are termed focal to bilateral. (Where both sides of the brain or the whole brain are involved from the onset the seizures are known as generalized seizures and may be tonic clonic.^[7] The arms, trunk, and legs stiffen (the tonic phase), in either a flexed or extended position, and then jerk (the clonic phase). These were previously known as grand mal seizures.^[12] The word grand mal comes from the French term, meaning major affliction.^{[citation needed]}

Postictal period

There is some period of recovery in which neurological function is altered after each of these seizure types. This is the postictal state. The degree and length of postictal impairment directly correlates with the severity of the seizure type. Focal aware seizures often last less than sixty seconds; focal with impaired awareness seizures may last up to two minutes; and generalized tonic clonic seizures may last up to three minutes.^{[citation needed]} The postictal state in seizures other than focal aware may last much longer than the seizure itself.

Because a major function of the temporal lobe is short-term memory, a focal with impaired awareness seizure, and a focal to bilateral seizure can cause amnesia for the period of the seizure, meaning that the seizure may not be remembered.^{[citation needed]}

Complications and prognosis

Depression

Individuals with temporal lobe epilepsy have a higher prevalence of depression than the general population. Although the psychosocial impacts of epilepsy may be causative, there are also links in the phenomenology and neurobiology of TLE and depression.^[13]

Memory

Hippocampus

The temporal lobe and particularly the hippocampus plays an important role in memory processing. Declarative memory (memories which can be consciously recalled) is formed in the area of the hippocampus called the dentate gyrus.^{[citation needed]}

Temporal lobe epilepsy is associated with memory disorders and loss of memory. Animal models and clinical studies show that memory loss correlates with temporal lobe neuronal loss in temporal lobe epilepsy. Verbal memory deficit correlates with pyramidal cell loss in TLE. This is more so on the left in verbal memory loss. Neuronal loss on the right is more prominent in non-verbal (visuospatial memory loss).^{[14][15][16][17][18]}

Childhood onset

After childhood onset, one third will "grow out" of TLE, finding a lasting remission up to an average of 20 years. The finding of a lesion such as hippocampal sclerosis (a scar in the hippocampus), tumour, or dysplasia, on magnetic resonance imaging (MRI) predicts the intractability of seizures.^[19]

Personality

The effect of temporal lobe epilepsy on personality is an historical observation dating to the 1800s. Personality and behavioural change in temporal lobe epilepsy is seen as a chronic condition when it persists for more than three months.^[20]

Geschwind syndrome is a set of behavioural phenomena seen in some people with TLE. Documented by Norman Geschwind, signs include: hypergraphia (compulsion to write (or draw) excessively), hyperreligiosity (intense religious or philosophical experiences or interests), hyposexuality (reduced sexual interest or drive), circumstantiality (result of a non-linear thought pattern, talks at length about irrelevant and trivial details).^[21] The personality changes generally vary by hemisphere.^[21]

The existence of a "temporal lobe epileptic personality" and Geschwind syndrome has been disputed and research is inconclusive.^[21]

Diagnosis

Epileptic spike and wave discharges monitored with EEG

The diagnosis of temporal lobe epilepsy can include the following methods:^[22] Magnetic resonance imaging (MRI), CT scans, positron emission tomography (PET), EEG, and magnetoencephalography.

Differential diagnosis

Other medical conditions with similar symptoms include panic attacks, psychosis spectrum disorders, tardive dyskinesia, and occipital lobe epilepsy.^[23]

Causes

The causes of TLE include mesial temporal sclerosis, traumatic brain injury, brain infections, such as encephalitis and meningitis, hypoxic brain injury, stroke, cerebral tumours, and genetic syndromes. Temporal lobe epilepsy is not the result of psychiatric illness or fragility of the personality.^[12]

Febrile seizures

Although the theory is controversial, there is a link between febrile seizures (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy, at least epidemiologically.^{[24][25][26][27]}

Human herpes virus 6

Reelin

In the mid 1980s, human herpesvirus 6 (HHV-6) was suggested as a possible causal link between febrile convulsions and mesial temporal lobe epilepsy. However, although the virus is found in temporal lobe tissue at surgery for TLE, it has not been recognised as a major factor in febrile seizures or TLE.^[28][29][30]

Reelin

Dispersion of the granule cell layer in the hippocampal dentate gyrus is occasionally seen in temporal lobe epilepsy and has been linked to the downregulation of reelin, a protein that normally keeps the layer compact by containing neuronal migration. It is unknown whether changes in reelin expression play a role in epilepsy.^[31][32]

Pathophysiology

Neuronal loss

In TLE, there is loss of neurons in region CA1 and CA3 of the hippocampus.^[33][34] There is also damage to mossy cells and inhibitory interneurons in the hilar region of the hippocampus (region IV) and to the granule cells of the dentate gyrus. In animal models, neuronal loss occurs during seizures but in humans, neuronal loss predates the first seizure and does not necessarily continue with seizure activity.^{[35][36][37][38][39]} The loss of the GABA-mediated inhibitory interneurons may increase the hyperexcitability of neurons of the hippocampus leading to recurrent seizures.^[40] According to the "dormant basket cell" hypothesis, mossy cells normally excite basket cells which in turn, inhibit granule cells. Loss of mossy cells lowers the threshold of action potentials of the granule cells.^[41]

GABA reversal

In certain patients with temporal lobe epilepsy it has been found that the subiculum could generate epileptic activity. It has been found that GABA reversal potential is depolarising^[42] in the subpopulation of the pyramidal cells due to the lack of KCC2 co-transporter. It has been shown that it is theoretically possible to generate seizures in the neural networks due to down-regulation of KCC2,^[43] consistent with the chloride measurements during the transition to seizure^[44] and KCC2 blockade experiments.^[45]

Granule cell dispersion in the dentate gyrus

Granule cell dispersion is a type of developmental migration and a pathological change found in the TLE brain which was first described in 1990.^[46][47] The granule cells of the dentate gyrus are tightly packed forming a uniform, laminated layer with no monosynaptic connections.^[48] This structure provides a filter for the excitability of neurons.^[48]

In TLE, granule cells are lost, the structure is no longer closely packed and there are changes in the orientation of dendrites.^[47][49] These changes may or may not be epileptogenic. For instance, if the dendrites of granule cells reconnect, it may be in a way (through the laminar planes) that allows hyperexcitability.^[36] However, not all patients have granule cell dispersion.^{[33](p387–389)}

Aberrant mossy fiber sprouting

Mossy fibers are the axons of granule cells. They project into the hilus of the dentate gyrus and stratum lucidum in the CA3 region giving inputs to both excitatory and inhibitory neurons.^[48][50][51]

In the TLE brain, where granule cells are damaged or lost, axons, the mossy fibres, 'sprout' in order to reconnect to other granule cell dendrites. This is an example of synaptic reorganization. This was noted in human tissue in 1974 and in animal models in 1985. In TLE, the sprouting mossy fibres are larger than in the normal brain and their connections may be aberrant. Mossy fibre sprouting continues from one week to two months after injury.^{[33](p416–431)[48][52][53][54]}

Aberrant mossy fibre sprouting may create excitatory feedback circuits that lead to temporal lobe seizures. This is evident in intracellular recordings.^[55] Stimulation of aberrant mossy fibre areas increases the excitatory postsynaptic potential response.^[56][57]

However, aberrant mossy fiber sprouting may inhibit excitatory transmission by synapsing with basket cells which are inhibitory neurons and by releasing GABA and neuropeptide Y which are inhibitory neurotransmitters. Also, in animal models, granule cell hyper-excitability is recorded before aberrant mossy fibre sprouting has occurred.^{[58][59][60][61]}

Treatments

Anticonvulsants

Many anticonvulsant oral medications are available for the management of temporal lobe seizures. Most anticonvulsants function by decreasing the excitation of neurons, for example, by blocking fast or slow sodium channels or by modulating calcium channels; or by enhancing the inhibition of neurons, for example by potentiating the effects of inhibitory neurotransmitters like GABA.^{[citation needed]}

In TLE, the most commonly used older medications are phenytoin, carbamazepine, primidone, valproate, and phenobarbital. Newer drugs, such as gabapentin, topiramate, levetiracetam, lamotrigine, pregabalin, tiagabine, lacosamide, and zonisamide promise similar effectiveness, with possibly fewer side-effects. Felbamate and vigabatrin are newer, but can have serious adverse effects so they are not considered as first-line treatments.

Up to one third of patients with medial temporal lobe epilepsy will not have adequate seizure control with medication alone. For patients with medial TLE whose seizures remain uncontrolled after trials of several types of anticonvulsants (that is, the epilepsy is intractable), surgical excision of the affected temporal lobe may be considered.^[62]

Surgical interventions

Epilepsy surgery has been performed since the 1860s and doctors have observed that it is highly effective in producing freedom from seizures. However, it was not until 2001 that a scientifically sound study was carried out to examine the effectiveness of temporal lobectomy.^[63]
Temporal lobe surgery can be complicated by decreased cognitive function. However, after temporal lobectomy, memory function is supported by the opposite temporal lobe; and recruitment of the frontal lobe.^[64][65] Cognitive rehabilitation may also help.^[66]

Other treatments

Where surgery is not recommended, further management options include new (including experimental) anticonvulsants, and vagus nerve stimulation. The ketogenic diet is also recommended for children, and some adults.^[67] Other options include brain cortex responsive neural stimulators, deep brain stimulation, stereotactic radiosurgery, such as the gamma knife, and laser ablation.^[68]

Link with religiosity

The first to record and catalog the abnormal symptoms and signs of TLE was Norman Geschwind. He found a constellation of symptoms that included hypergraphia, hyperreligiosity, collapse, and pedantism, now called Geschwind syndrome.

Vilayanur S. Ramachandran explored the neural basis of the hyperreligiosity seen in TLE using the galvanic skin response (GSR), which correlates with emotional arousal, to determine whether the hyperreligiosity seen in TLE was due to an overall heightened emotional state or was specific to religious stimuli. Ramachandran presented two subjects with neutral, sexually arousing and religious words while measuring GSR. Ramachandran was able to show that patients with TLE showed enhanced emotional responses to the religious words, diminished responses to the sexually charged words, and normal responses to the neutral words. This study was presented as an abstract at a neuroscience conference and referenced in Ramachandran's book, Phantoms in the Brain,^[69] but it has never been published in the peer-reviewed scientific press.^[70]

A study in 2015, reported that intrinsic religiosity and religiosity outside of organized religion were higher in patients with epilepsy than in controls.^[71] Lower education level, abnormal background EEG activity, and hippocampal sclerosis have been found to be contributing factors for religiosity in Temporal Lobe Epilepsy.^[72]

Temporal lobe epilepsy has been suggested as a physical explanation for the revelatory experiences of prominent religious figures such as Abraham, Moses, Jesus, Mohammed, Saint Paul, and Joseph Smith. These experiences are described as complex interactions with their visions, but lacking the stereotypy, amnestic periods, and automatisms or generalized motor events, which are characteristic of TLE. Psychiatric conditions with psychotic spectrum symptoms may be a more plausible physical explanation of these experiences.^[73] Pope Pius IX's doctrine of the immaculate conception is thought to have been influenced by his forensically diagnosed partial epilepsy.^[74] It has also been suggested that the visions of Joan of Arc were probably an expression of partial epilepsy.^[75] In 2016, a case history found that a temporal lobe epileptic experienced a vision of God following a temporal lobe seizure, while undergoing EEG monitoring. The patient reported that God had sent him to the world to "bring redemption to the people of Israel".^[76] The purported link between TLE and religiosity has inspired work by Michael Persinger and many other researchers in the field of neurotheology, but some have questioned the evidence for a link between temporal lobe epilepsy and religiosity.^[70][77] The novel, Lying Awake, by Mark Salzman, deals with topic of temporal lobe epilepsy and religion.

Neuroscience of religion

From Wikipedia, the free encyclopedia

The neuroscience of religion, also known as neurotheology and as spiritual neuroscience, attempts to explain religious experience and behaviour in neuroscientific terms. It is the study of correlations of neural phenomena with subjective experiences of spirituality and hypotheses to explain these phenomena. This contrasts with the psychology of religion which studies mental, rather than neural, states.

Proponents of the neuroscience of religion say there is a neurological and evolutionary basis for subjective experiences traditionally categorized as spiritual or religious.^[3] The field has formed the basis of several popular science books,^[4][5][6] but has received criticism from psychologists.^[2]

Introduction

"Neurotheology" is a neologism that describes the scientific study of the neural correlates of religious or spiritual beliefs, experiences and practices. Other researchers prefer to use terms like "spiritual neuroscience" or "neuroscience of religion". Researchers in the field attempt to explain the neurological basis for religious experiences, such as:^[7]

• The perception that time, fear or self-consciousness have dissolved
• Spiritual awe
• Oneness with the universe
• Ecstatic trance
• Sudden enlightenment^[8]
• Altered states of consciousness

Terminology

Aldous Huxley used the term neurotheology for the first time in the utopian novel Island. The discipline studies the cognitive neuroscience of religious experience and spirituality. The term is also sometimes used in a less scientific context or a philosophical context. Some of these uses, according to the mainstream scientific community, qualify as pseudoscience. Huxley used it mainly in a philosophical context.

The use of the term neurotheology in published scientific work is currently uncommon. A search on the citation indexing service provided by Institute for Scientific Information returns five articles. Three of these are published in the journal Zygon: Journal of Religion & Science, while two are published in American Behavioral Scientist. Work on the neural basis of spirituality has, however, occurred sporadically throughout the 20th century.

Theoretical work

In an attempt to focus and clarify what was a growing interest in this field, in 1994 educator and businessman Laurence O. McKinney published the first book on the subject, titled "Neurotheology: Virtual Religion in the 21st Century", written for a popular audience but also promoted in the theological journal Zygon.^[9] According to McKinney, neurotheology sources the basis of religious inquiry in relatively recent developmental neurophysiology. According to McKinney's theory, pre-frontal development, in humans, creates an illusion of chronological time as a fundamental part of normal adult cognition past the age of three. The inability of the adult brain to retrieve earlier images experienced by an infantile brain creates questions such as "where did I come from" and "where does it all go", which McKinney suggests led to the creation of various religious explanations. The experience of death as a peaceful regression into timelessness as the brain dies won praise from readers as varied as author Arthur C. Clarke, eminent theologian Harvey Cox, and the Dalai Lama and sparked a new interest in the field.^{[citation needed]}

What Andrew B. Newberg and others "discovered is that intensely focused spiritual contemplation triggers an alteration in the activity of the brain that leads one to perceive transcendent religious experiences as solid, tangible reality. In other words, the sensation that Buddhists call oneness with the universe."^[10] The orientation area requires sensory input to do its calculus. "If you block sensory inputs to this region, as you do during the intense concentration of meditation, you prevent the brain from forming the distinction between self and not-self," says Newberg. With no information from the senses arriving, the left orientation area cannot find any boundary between the self and the world. As a result, the brain seems to have no choice but "to perceive the self as endless and intimately interwoven with everyone and everything." "The right orientation area, equally bereft of sensory data, defaults to a feeling of infinite space. The meditators feel that they have touched infinity."^[11]

The radical Catholic theologian Eugen Drewermann developed a two-volume critique of traditional conceptions of God and the soul and a reinterpretation of religion (Modern Neurology and the Question of God) based on current neuroscientific research.^[12]

However, it has also been argued "that neurotheology should be conceived and practiced within a theological framework."^[13] Furthermore, it has been suggested that creating a separate category for this kind of research is moot since conventional Behavioural and Social Neurosciences disciplines can handle any empirical investigation of this nature.^[14]

Various theories regarding the evolutionary origin of religion and the evolutionary psychology of religion have been proposed.

Experimental work

In 1969, British biologist Alister Hardy founded a Religious Experience Research Centre at Oxford after retiring from his post as Linacre Professor of Zoology. Citing William James's The Varieties of Religious Experience (1902), he set out to collect first-hand accounts of numinous experiences. He was awarded the Templeton Prize before his death in 1985. His successor David Hay suggested in God’s Biologist: A life of Alister Hardy (2011) that the RERC later dispersed as investigators turned to newer techniques of scientific investigation.

Magnetic stimulation studies

During the 1980s Michael Persinger stimulated the temporal lobes of human subjects with a weak magnetic field using an apparatus that popularly became known as the "God helmet"^[15] and reported that many of his subjects claimed to experience a "sensed presence" during stimulation.^[16] This work has been criticised,^[2][17][18] though some researchers ^[19] have published a replication of one God Helmet experiment.^[20]

Granqvist et al. claimed that Persinger's work was not "double-blind." Participants were often graduate students who knew what sort of results to expect, and there was the risk that the experimenters' expectations would be transmitted to subjects by unconscious cues. The participants were frequently given an idea of the purpose of the study by being asked to fill in questionnaires designed to test their suggestibility to paranormal experiences before the trials were conducted. Granqvist et al. failed to replicate Persinger's experiments double-blinded, and concluded that the presence or absence of the magnetic field had no relationship with any religious or spiritual experience reported by the participants, but was predicted entirely by their suggestibility and personality traits. Following the publication of this study, Persinger et al. dispute this.^[21] One published attempt to create a "haunted room" using environmental "complex" electromagnetic fields based on Persinger's theoretical and experimental work did not produce the sensation of a "sensed presence" and found that reports of unusual experiences were uncorrelated with the presence or absence of these fields. As in the study by Granqvist et al., reports of unusual experiences were instead predicted by the personality characteristics and suggestibility of participants.^[22] One experiment with a commercial version of the God helmet found no difference in response to graphic images whether the device was on or off.^[23][24]

Neuropsychology and neuroimaging

The first researcher to note and catalog the abnormal experiences associated with temporal lobe epilepsy (TLE) was neurologist Norman Geschwind, who noted a set of religious behavioral traits associated with TLE seizures.^[25] These include hypergraphia, hyperreligiosity, reduced sexual interest, fainting spells, and pedantism, often collectively ascribed to a condition known as Geschwind syndrome.

Vilayanur S. Ramachandran explored the neural basis of the hyperreligiosity seen in TLE using the galvanic skin response (GSR), which correlates with emotional arousal, to determine whether the hyperreligiosity seen in TLE was due to an overall heightened emotional state or was specific to religious stimuli. Ramachandran presented two subjects with neutral, sexually arousing and religious words while measuring GSR. Ramachandran was able to show that patients with TLE showed enhanced emotional responses to the religious words, diminished responses to the sexually charged words, and normal responses to the neutral words. This study was presented as an abstract at a neuroscience conference and referenced in Ramachandran's book, Phantoms in the Brain,^[26] but it has never been published in the peer-reviewed scientific press.

Research by Mario Beauregard at the University of Montreal, using fMRI on Carmelite nuns, has purported to show that religious and spiritual experiences include several brain regions and not a single 'God spot'. As Beauregard has said, "There is no God spot in the brain. Spiritual experiences are complex, like intense experiences with other human beings."^[27] The neuroimaging was conducted when the nuns were asked to recall past mystical states, not while actually undergoing them; "subjects were asked to remember and relive (eyes closed) the most intense mystical experience ever felt in their lives as a member of the Carmelite Order."^[28] A 2011 study by researchers at the Duke University Medical Center found hippocampal atrophy is associated with older adults who report life-changing religious experiences, as well as those who are "born-again Protestants, Catholics, and those with no religious affiliation".^[29]

A 2016 study using fMRI found "a recognizable feeling central to ... (Mormon)... devotional practice was reproducibly associated with activation in nucleus accumbens, ventromedial prefrontal cortex, and frontal attentional regions. Nucleus accumbens activation preceded peak spiritual feelings by 1–3 s and was replicated in four separate tasks. ... The association of abstract ideas and brain reward circuitry may interact with frontal attentional and emotive salience processing, suggesting a mechanism whereby doctrinal concepts may come to be intrinsically rewarding and motivate behavior in religious individuals."^[30]

Psychopharmacology

Some scientists working in the field hypothesize that the basis of spiritual experience arises in neurological physiology. Speculative suggestions have been made that an increase of N,N-dimethyltryptamine levels in the pineal gland contribute to spiritual experiences.^[31][32] Scientific studies confirming this have yet to be published. It has also been suggested that stimulation of the temporal lobe by psychoactive ingredients of 'Magic Mushrooms' mimics religious experiences.^[33] This hypothesis has found laboratory validation with respect to psilocybin.

Evolutionary origin of religions

From Wikipedia, the free encyclopedia

The emergence of religious behavior by the Neolithic period has been discussed in terms of evolutionary psychology, the origin of language and mythology, cross-cultural comparison of the anthropology of religion, as well as evidence for spirituality or cultic behavior in the Upper Paleolithic, and similarities in great ape behavior.

Nonhuman religious behaviour

Humanity's closest living relatives are common chimpanzees and bonobos.^[1][2] These primates share a common ancestor with humans who lived between six and eight million years ago. It is for this reason that chimpanzees and bonobos are viewed as the best available surrogate for this common ancestor. Barbara King argues that while non-human primates are not religious, they do exhibit some traits that would have been necessary for the evolution of religion. These traits include high intelligence, a capacity for symbolic communication, a sense of social norms, realization of "self" and a concept of continuity.^[3][4] There is inconclusive evidence that Homo neanderthalensis may have buried their dead which is evidence of the use of ritual. The use of burial rituals is thought to be evidence of religious activity, and there is no other evidence that religion existed in human culture before humans reached behavioral modernity.^[5]

Elephants demonstrate rituals around their deceased, which includes long periods of silence and mourning at the point of death and a process of returning to grave sites and caressing the remains.^[6][7] Some evidence suggests that many species grieve death and loss.^[8]

Setting the stage for human religion

Increased brain size

In this set of theories, the religious mind is one consequence of a brain that is large enough to formulate religious and philosophical ideas.^[9] During human evolution, the hominid brain tripled in size, peaking 500,000 years ago. Much of the brain's expansion took place in the neocortex. The cerebral neocortex is presumed to be responsible for the neuronal computations underlying complex phenomena such as perception, thought, language, attention, episodic memory and voluntary movement.^[10] According to Dunbar's theory, the relative neocortex size of any species correlates with the level of social complexity of the particular species.^[11] The neocortex size correlates with a number of social variables that include social group size and complexity of mating behaviors.^[12] In chimpanzees the neocortex occupies 50% of the brain, whereas in modern humans it occupies 80% of the brain.^[13]

Robin Dunbar argues that the critical event in the evolution of the neocortex took place at the speciation of archaic homo sapiens about 500,000 years ago. His study indicates that only after the speciation event is the neocortex large enough to process complex social phenomena such as language and religion. The study is based on a regression analysis of neocortex size plotted against a number of social behaviors of living and extinct hominids.^[14]

Stephen Jay Gould suggests that religion may have grown out of evolutionary changes which favored larger brains as a means of cementing group coherence among savannah hunters, after that larger brain enabled reflection on the inevitability of personal mortality.^[15]

Tool use

Lewis Wolpert argues that causal beliefs that emerged from tool use played a major role in the evolution of belief. The manufacture of complex tools requires creating a mental image of an object which does not exist naturally before actually making the artifact. Furthermore, one must understand how the tool would be used, that requires an understanding of causality.^[16] Accordingly, the level of sophistication of stone tools is a useful indicator of causal beliefs.^[17] Wolpert contends use of tools composed of more than one component, such as hand axes, represents an ability to understand cause and effect. However, recent studies of other primates indicate that causality may not be a uniquely human trait. For example, chimpanzees have been known to escape from pens closed with multiple latches, which was previously thought could only have been figured out by humans who understood causality. Chimpanzees are also known to mourn the dead, and notice things that have only aesthetic value, like sunsets, both of which may be considered to be components of religion or spirituality.^[18] The difference between the comprehension of causality by humans and chimpanzees is one of degree. The degree of comprehension in an animal depends upon the size of the prefrontal cortex: the greater the size of the prefrontal cortex the deeper the comprehension.^[19]

Development of language

Religion requires a system of symbolic communication, such as language, to be transmitted from one individual to another. Philip Lieberman states "human religious thought and moral sense clearly rest on a cognitive-linguistic base".^[20] From this premise science writer Nicholas Wade states:

"Like most behaviors that are found in societies throughout the world, religion must have been present in the ancestral human population before the dispersal from Africa 50,000 years ago. Although religious rituals usually involve dance and music, they are also very verbal, since the sacred truths have to be stated. If so, religion, at least in its modern form, cannot pre-date the emergence of language. It has been argued earlier that language attained its modern state shortly before the exodus from Africa. If religion had to await the evolution of modern, articulate language, then it too would have emerged shortly before 50,000 years ago."^[21]

Another view distinguishes individual religious belief from collective religious belief. While the former does not require prior development of language, the latter does. The individual human brain has to explain a phenomenon in order to comprehend and relate to it. This activity predates by far the emergence of language and may have caused it. The theory is, belief in the supernatural emerges from hypotheses arbitrarily assumed by individuals to explain natural phenomena that cannot be explained otherwise. The resulting need to share individual hypotheses with others leads eventually to collective religious belief. A socially accepted hypothesis becomes dogmatic backed by social sanction.

Morality and group living

Frans de Waal and Barbara King both view human morality as having grown out of primate sociality. Though morality awareness may be a unique human trait, many social animals, such as primates, dolphins and whales, have been known to exhibit pre-moral sentiments. According to Michael Shermer, the following characteristics are shared by humans and other social animals, particularly the great apes:

"attachment and bonding, cooperation and mutual aid, sympathy and empathy, direct and indirect reciprocity, altruism and reciprocal altruism, conflict resolution and peacemaking, deception and deception detection, community concern and caring about what others think about you, and awareness of and response to the social rules of the group".^[22]

De Waal contends that all social animals have had to restrain or alter their behavior for group living to be worthwhile. Pre-moral sentiments evolved in primate societies as a method of restraining individual selfishness and building more cooperative groups. For any social species, the benefits of being part of an altruistic group should outweigh the benefits of individualism. For example, a lack of group cohesion could make individuals more vulnerable to attack from outsiders. Being part of a group may also improve the chances of finding food. This is evident among animals that hunt in packs to take down large or dangerous prey.

All social animals have hierarchical societies in which each member knows its own place. Social order is maintained by certain rules of expected behavior and dominant group members enforce order through punishment. However, higher order primates also have a sense of fairness. In a 2008 study, de Waal and colleagues put two capuchin monkeys side by side and gave them a simple task to complete: Giving a rock to the experimenter. They were given cucumbers as a reward for executing the task, and the monkeys obliged. But if one of the monkeys was given grapes, something interesting happened: After receiving the first piece of cucumber, the capuchin monkey gave the experimenter a rock as expected. But upon seeing that the other monkey got grapes, the capuchin monkey threw away the next piece of cucumber that was given to him.^[23]

Chimpanzees live in fission-fusion groups that average 50 individuals. It is likely that early ancestors of humans lived in groups of similar size. Based on the size of extant hunter-gatherer societies, recent Paleolithic hominids lived in bands of a few hundred individuals. As community size increased over the course of human evolution, greater enforcement to achieve group cohesion would have been required. Morality may have evolved in these bands of 100 to 200 people as a means of social control, conflict resolution and group solidarity. According to Dr. de Waal, human morality has two extra levels of sophistication that are not found in primate societies. Humans enforce their society's moral codes much more rigorously with rewards, punishments and reputation building. Humans also apply a degree of judgment and reason not otherwise seen in the animal kingdom.

Psychologist Matt J. Rossano argues that religion emerged after morality and built upon morality by expanding the social scrutiny of individual behavior to include supernatural agents. By including ever-watchful ancestors, spirits and gods in the social realm, humans discovered an effective strategy for restraining selfishness and building more cooperative groups.^[24] The adaptive value of religion would have enhanced group survival.^[25][26] Rossano is referring here to collective religious belief and the social sanction that institutionalized morality. According to Rossano's teaching, individual religious belief is thus initially epistemological, not ethical, in nature.

Evolutionary psychology of religion

Cognitive scientists underlined that religions may be explained as a result of the brain architecture that expressed in early Homo genus, through the history of life. However, there is disagreement on the exact mechanisms that drove the evolution of the religious mind. The two main schools of thought hold that either religion evolved due to natural selection and has selective advantage, or that religion is an evolutionary byproduct of other mental adaptations.^[27] Stephen Jay Gould, for example, believed that religion was an exaptation or a spandrel, in other words that religion evolved as byproduct of psychological mechanisms that evolved for other reasons.^[28][29][30]
Such mechanisms may include the ability to infer the presence of organisms that might do harm (agent detection), the ability to come up with causal narratives for natural events (etiology), and the ability to recognize that other people have minds of their own with their own beliefs, desires and intentions (theory of mind). These three adaptations (among others) allow human beings to imagine purposeful agents behind many observations that could not readily be explained otherwise, e.g. thunder, lightning, movement of planets, complexity of life.^[31] The emergence of collective religious belief identified the agents as deities that standardized the explanation.^[32]

Some scholars have suggested that religion is genetically "hardwired" into the human condition. One controversial proposal, the God gene hypothesis, states that some variants of a specific gene, the VMAT2 gene, predispose to spirituality.^[33]

Another view is based on the concept of the triune brain: the reptilian brain, the limbic system, and the neocortex, proposed by Paul D. MacLean. Collective religious belief draws upon the emotions of love, fear, and gregariousness and is deeply embedded in the limbic system through socio-biological conditioning and social sanction. Individual religious belief utilizes reason based in the neocortex and often varies from collective religion. The limbic system is much older in evolutionary terms than the neocortex and is, therefore, stronger than it much in the same way as the reptilian is stronger than both the limbic system and the neocortex.

Yet another view is that the behavior of people who participate in a religion makes them feel better and this improves their fitness, so that there is a genetic selection in favor of people who are willing to believe in religion. Specifically, rituals, beliefs, and the social contact typical of religious groups may serve to calm the mind (for example by reducing ambiguity and the uncertainty due to complexity) and allow it to function better when under stress.^[34] This would allow religion to be used as a powerful survival mechanism, particularly in facilitating the evolution of hierarchies of warriors, which if true, may be why many modern religions tend to promote fertility and kinship.

Still another view, proposed by F.H. Previc, is that human religion was a product of an increase in dopaminergic functions in the human brain and a general intellectual expansion beginning around 80 kya.^[35][36][37] Dopamine promotes an emphasis on distant space and time, which is critical for the establishment of religious experience.^[38] While the earliest shamanic cave paintings date back around 40 kya, the use of ochre for rock art predates this and there is clear evidence for abstract thinking along the coast of South Africa 80 kya.

Prehistoric evidence of religion

The exact time when humans first became religious remains unknown, however research in evolutionary archaeology shows credible evidence of religious-cum-ritualistic behaviour from around the Middle Paleolithic era (45-200 thousand years ago).^[39]

Paleolithic burials

The earliest evidence of religious thought is based on the ritual treatment of the dead. Most animals display only a casual interest in the dead of their own species.^[40] Ritual burial thus represents a significant change in human behavior. Ritual burials represent an awareness of life and death and a possible belief in the afterlife. Philip Lieberman states "burials with grave goods clearly signify religious practices and concern for the dead that transcends daily life."^[20]

The earliest evidence for treatment of the dead comes from Atapuerca in Spain. At this location the bones of 30 individuals believed to be Homo heidelbergensis have been found in a pit.^[41] Neanderthals are also contenders for the first hominids to intentionally bury the dead. They may have placed corpses into shallow graves along with stone tools and animal bones. The presence of these grave goods may indicate an emotional connection with the deceased and possibly a belief in the afterlife. Neanderthal burial sites include Shanidar in Iraq and Krapina in Croatia and Kebara Cave in Israel.^{[42][43][43][44]}

The earliest known burial of modern humans is from a cave in Israel located at Qafzeh. Human remains have been dated to 100,000 years ago. Human skeletons were found stained with red ochre. A variety of grave goods were found at the burial site. The mandible of a wild boar was found placed in the arms of one of the skeletons.^[45] Philip Lieberman states:

"Burial rituals incorporating grave goods may have been invented by the anatomically modern hominids who emigrated from Africa to the Middle East roughly 100,000 years ago".^[45]

Matt Rossano suggests that the period between 80,000–60,000 years before present, following the retreat of humans from the Levant to Africa, was a crucial period in the evolution of religion.^[46]

Use of symbolism

The use of symbolism in religion is a universal established phenomenon. Archeologist Steven Mithen contends that it is common for religious practices to involve the creation of images and symbols to represent supernatural beings and ideas. Because supernatural beings violate the principles of the natural world, there will always be difficulty in communicating and sharing supernatural concepts with others. This problem can be overcome by anchoring these supernatural beings in material form through representational art. When translated into material form, supernatural concepts become easier to communicate and understand.^[47] Due to the association of art and religion, evidence of symbolism in the fossil record is indicative of a mind capable of religious thoughts. Art and symbolism demonstrates a capacity for abstract thought and imagination necessary to construct religious ideas. Wentzel van Huyssteen states that the translation of the non-visible through symbolism enabled early human ancestors to hold beliefs in abstract terms.^[48]

Some of the earliest evidence of symbolic behavior is associated with Middle Stone Age sites in Africa. From at least 100,000 years ago, there is evidence of the use of pigments such as red ochre. Pigments are of little practical use to hunter gatherers, thus evidence of their use is interpreted as symbolic or for ritual purposes. Among extant hunter gatherer populations around the world, red ochre is still used extensively for ritual purposes. It has been argued that it is universal among human cultures for the color red to represent blood, sex, life and death.^[49]

The use of red ochre as a proxy for symbolism is often criticized as being too indirect. Some scientists, such as Richard Klein and Steven Mithen, only recognize unambiguous forms of art as representative of abstract ideas. Upper paleolithic cave art provides some of the most unambiguous evidence of religious thought from the paleolithic. Cave paintings at Chauvet depict creatures that are half human and half animal.

Origins of organized religion

Organised religion traces its roots to the neolithic revolution that began 11,000 years ago in the Near East but may have occurred independently in several other locations around the world. The invention of agriculture transformed many human societies from a hunter-gatherer lifestyle to a sedentary lifestyle. The consequences of the neolithic revolution included a population explosion and an acceleration in the pace of technological development. The transition from foraging bands to states and empires precipitated more specialized and developed forms of religion that reflected the new social and political environment. While bands and small tribes possess supernatural beliefs, these beliefs do not serve to justify a central authority, justify transfer of wealth or maintain peace between unrelated individuals. Organized religion emerged as a means of providing social and economic stability through the following ways:

• Justifying the central authority, which in turn possessed the right to collect taxes in return for providing social and security services.
• Bands and tribes consist of small number of related individuals. However, states and nations are composed of many thousands of unrelated individuals. Jared Diamond argues that organized religion served to provide a bond between unrelated individuals who would otherwise be more prone to enmity. In his book Guns, Germs, and Steel he argues that the leading cause of death among hunter-gatherer societies is murder.^[50]
• Religions that revolved around moralizing gods may have facilitated the rise of large, cooperative groups of unrelated individuals.^[51]

The states born out of the Neolithic revolution, such as those of Ancient Egypt and Mesopotamia, were theocracies with chiefs, kings and emperors playing dual roles of political and spiritual leaders.^[22] Anthropologists have found that virtually all state societies and chiefdoms from around the world have been found to justify political power through divine authority. This suggests that political authority co-opts collective religious belief to bolster itself.^[22]

Invention of writing

Following the neolithic revolution, the pace of technological development (cultural evolution) intensified due to the invention of writing 5000 years ago. Symbols that became words later on made effective communication of ideas possible. Printing invented only over a thousand years ago increased the speed of communication exponentially and became the main spring of cultural evolution. Writing is thought to have been first invented in either Sumeria or Ancient Egypt and was initially used for accounting. Soon after, writing was used to record myth. The first religious texts mark the beginning of religious history. The Pyramid Texts from ancient Egypt are one of the oldest known religious texts in the world, dating to between 2400–2300 BCE.^[52][53][54] Writing played a major role in sustaining and spreading organized religion. In pre-literate societies, religious ideas were based on an oral tradition, the contents of which were articulated by shamans and remained limited to the collective memories of the society's inhabitants. With the advent of writing, information that was not easy to remember could easily be stored in sacred texts that were maintained by a select group (clergy). Humans could store and process large amounts of information with writing that otherwise would have been forgotten. Writing therefore enabled religions to develop coherent and comprehensive doctrinal systems that remained independent of time and place.^[55] Writing also brought a measure of objectivity to human knowledge. Formulation of thoughts in words and the requirement for validation made mutual exchange of ideas and the sifting of generally acceptable from not acceptable ideas possible. The generally acceptable ideas became objective knowledge reflecting the continuously evolving framework of human awareness of reality that Karl Popper calls 'verisimilitude' – a stage on the human journey to truth.

Creation myth

From Wikipedia, the free encyclopedia

 

The Creation (c. 1896–1902) by James Tissot^[1]

A creation myth (or cosmogonic myth) is a symbolic narrative of how the world began and how people first came to inhabit it. While in popular usage the term myth often refers to false or fanciful stories, members of cultures often ascribe varying degrees of truth to their creation myths. In the society in which it is told, a creation myth is usually regarded as conveying profound truths, metaphorically, symbolically and sometimes in a historical or literal sense. They are commonly, although not always, considered cosmogonical myths – that is, they describe the ordering of the cosmos from a state of chaos or amorphousness.

Creation myths often share a number of features. They often are considered sacred accounts and can be found in nearly all known religious traditions.^[10] They are all stories with a plot and characters who are either deities, human-like figures, or animals, who often speak and transform easily.^[11] They are often set in a dim and nonspecific past that historian of religion Mircea Eliade termed in illo tempore ("at that time").^[10][12] Creation myths address questions deeply meaningful to the society that shares them, revealing their central worldview and the framework for the self-identity of the culture and individual in a universal context.^[13]

Creation myths develop in oral traditions and therefore typically have multiple versions;^[3] found throughout human culture, they are the most common form of myth.^[7]

Definitions

Creation myth definitions from modern references:

• A "symbolic narrative of the beginning of the world as understood in a particular tradition and community. Creation myths are of central importance for the valuation of the world, for the orientation of humans in the universe, and for the basic patterns of life and culture."^[14]
• "Creation myths tell us how things began. All cultures have creation myths; they are our primary myths, the first stage in what might be called the psychic life of the species. As cultures, we identify ourselves through the collective dreams we call creation myths, or cosmogonies. … Creation myths explain in metaphorical terms our sense of who we are in the context of the world, and in so doing they reveal our real priorities, as well as our real prejudices. Our images of creation say a great deal about who we are."^[15]
• A "philosophical and theological elaboration of the primal myth of creation within a religious community. The term myth here refers to the imaginative expression in narrative form of what is experienced or apprehended as basic reality … The term creation refers to the beginning of things, whether by the will and act of a transcendent being, by emanation from some ultimate source, or in any other way."^[16]

Religion professor Mircea Eliade defined the word myth in terms of creation:

Myth narrates a sacred history; it relates an event that took place in primordial Time, the fabled time of the "beginnings." In other words, myth tells how, through the deeds of Supernatural Beings, a reality came into existence, be it the whole of reality, the Cosmos, or only a fragment of reality – an island, a species of plant, a particular kind of human behavior, an institution.^[17]

Meaning and function

In Daoist creation myth, "The Way gave birth to unity; unity gave birth to duality; duality gave birth to trinity; trinity gave birth to the myriad creatures." (Daodejing, 4th century BCE)^[18]

All creation myths are in one sense etiological because they attempt to explain how the world was formed and where humanity came from.^[19] Myths attempt to explain the unknown and sometimes teach a lesson.^[20][21]

Ethnologists and anthropologists^[which?] who study these myths say that in the modern context theologians try to discern humanity's meaning from revealed truths and scientists investigate cosmology with the tools of empiricism and rationality, but creation myths define human reality in very different terms. In the past historians of religion and other students of myth thought of them as forms of primitive or early-stage science or religion and analyzed them in a literal or logical sense. However they are today seen as symbolic narratives which must be understood in terms of their own cultural context. Charles Long writes, "The beings referred to in the myth – gods, animals, plants – are forms of power grasped existentially. The myths should not be understood as attempts to work out a rational explanation of deity."^[22]

While creation myths are not literal explications they do serve to define an orientation of humanity in the world in terms of a birth story. They are the basis of a worldview that reaffirms and guides how people relate to the natural world, to any assumed spiritual world, and to each other. The creation myth acts as a cornerstone for distinguishing primary reality from relative reality, the origin and nature of being from non-being.^[23] In this sense they serve as a philosophy of life but one expressed and conveyed through symbol rather than systematic reason. And in this sense they go beyond etiological myths which mean to explain specific features in religious rites, natural phenomena or cultural life. Creation myths also help to orient human beings in the world, giving them a sense of their place in the world and the regard that they must have for humans and nature.^[2]

Historian David Christian has summarised issues common to multiple creation myths:

Each beginning seems to presuppose an earlier beginning. ... Instead of meeting a single starting point, we encounter an infinity of them, each of which poses the same problem. ... There are no entirely satisfactory solutions to this dilemma. What we have to find is not a solution but some way of dealing with the mystery .... And we have to do so using words. The words we reach for, from God to gravity, are inadequate to the task. So we have to use language poetically or symbolically; and such language, whether used by a scientist, a poet, or a shaman, can easily be misunderstood.^[24]

Classification

In Maya religion, the dwarf was an embodiment of the Maize God's helpers at creation.^[25]

Mythologists have applied various schemes to classify creation myths found throughout human cultures. Eliade and his colleague Charles Long developed a classification based on some common motifs that reappear in stories the world over. The classification identifies five basic types:^[26]
 

Brahmā, the Hindu deva of creation, emerges from a lotus risen from the navel of Viṣņu, who lies with Lakshmi on the serpent Ananta Shesha.

• Creation ex nihilo in which the creation is through the thought, word, dream or bodily secretions of a divine being.
• Earth diver creation in which a diver, usually a bird or amphibian sent by a creator, plunges to the seabed through a primordial ocean to bring up sand or mud which develops into a terrestrial world.
• Emergence myths in which progenitors pass through a series of worlds and metamorphoses until reaching the present world.
• Creation by the dismemberment of a primordial being.
• Creation by the splitting or ordering of a primordial unity such as the cracking of a cosmic egg or a bringing order from chaos.

Marta Weigle further developed and refined this typology to highlight nine themes, adding elements such as deus faber, a creation crafted by a deity, creation from the work of two creators working together or against each other, creation from sacrifice and creation from division/conjugation, accretion/conjunction, or secretion.^[26]

An alternative system based on six recurring narrative themes was designed by Raymond Van Over:^[26]

• Primeval abyss, an infinite expanse of waters or space.
• Originator deity which is awakened or an eternal entity within the abyss.
• Originator deity poised above the abyss.
• Cosmic egg or embryo.
• Originator deity creating life through sound or word.
• Life generating from the corpse or dismembered parts of an originator deity.

Ex nihilo

Creation on the exterior shutters of Hieronymus Bosch's triptych The Garden of Earthly Delights (1480–90)

The idea that God created the world out of nothing – ex nihilo – is central today to Judaism, Christianity and Islam, and the medieval Jewish philosopher Maimonides felt it was the only concept that the three religions shared.^[27] Nonetheless, the concept is not found in the entire Hebrew Bible.^[28] The authors of Genesis 1 were concerned not with the origins of matter (the material which God formed into the habitable cosmos), but with assigning roles so that the Cosmos should function.^[29] In the early 2nd century AD, early Christian scholars were beginning to see a tension between the idea of world-formation and the omnipotence of God, and by the beginning of the 3rd century creation ex nihilo had become a fundamental tenet of Christian theology.^[30]

Ex nihilo creation is found in creation stories from ancient Egypt, the Rig Veda, and many animistic cultures in Africa, Asia, Oceania and North America.^[31] The Debate between sheep and grain is an example of an even earlier form of ex nihilo creation myth from ancient Sumer.^[32] In most of these stories the world is brought into being by the speech, dream, breath, or pure thought of a creator but creation ex nihilo may also take place through a creator's bodily secretions.

The literal translation of the phrase ex nihilo is "from nothing" but in many creation myths the line is blurred whether the creative act would be better classified as a creation ex nihilo or creation from chaos. In ex nihilo creation myths the potential and the substance of creation springs from within the creator. Such a creator may or may not be existing in physical surroundings such as darkness or water, but does not create the world from them, whereas in creation from chaos the substance used for creation is pre-existing within the unformed void.^[33]

Creation from chaos

In creation from chaos myth, initially there is nothing but a formless, shapeless expanse. In these stories the word "chaos" means "disorder", and this formless expanse, which is also sometimes called a void or an abyss, contains the material with which the created world will be made. Chaos may be described as having the consistency of vapor or water, dimensionless, and sometimes salty or muddy. These myths associate chaos with evil and oblivion, in contrast to "order" (cosmos) which is the good. The act of creation is the bringing of order from disorder, and in many of these cultures it is believed that at some point the forces preserving order and form will weaken and the world will once again be engulfed into the abyss.^[34] One example is the Genesis creation myth from the first chapter of the Book of Genesis.

World parent

In one Maori creation myth, the primal couple are Rangi and Papa, depicted holding each other in a tight embrace.

There are two types of world parent myths, both describing a separation or splitting of a primeval entity, the world parent or parents. One form describes the primeval state as an eternal union of two parents, and the creation takes place when the two are pulled apart. The two parents are commonly identified as Sky (usually male) and Earth (usually female) who in the primeval state were so tightly bound to each other that no offspring could emerge. These myths often depict creation as the result of a sexual union, and serve as genealogical record of the deities born from it.^[35]

In the second form of world parent myth, creation itself springs from dismembered parts of the body of the primeval being. Often in these stories the limbs, hair, blood, bones or organs of the primeval being are somehow severed or sacrificed to transform into sky, earth, animal or plant life, and other worldly features. These myths tend to emphasize creative forces as animistic in nature rather than sexual, and depict the sacred as the elemental and integral component of the natural world.^[36] One example of this is the Norse creation myth described in Gylfaginning exactly in the poem Völuspá.^[37]

Emergence

In emergence myths humanity emerges from another world into the one they currently inhabit. The previous world is often considered the womb of the earth mother, and the process of emergence is likened to the act of giving birth. The role of midwife is usually played by a female deity, like the spider woman of Native American mythology. Male characters rarely figure into these stories, and scholars often consider them in counterpoint to male-oriented creation myths, like those of the ex nihilo variety.^[19]
 

In the kiva of both ancient and present-day Pueblo peoples, the sipapu is a small round hole in the floor that represents the portal through which the ancestors first emerged. (The larger hole is a fire pit, here in a ruin from the Mesa Verde National Park.)

Emergence myths commonly describe the creation of people and/or supernatural beings as a staged ascent or metamorphosis from nascent forms through a series of subterranean worlds to arrive at their current place and form. Often the passage from one world or stage to the next is impelled by inner forces, a process of germination or gestation from earlier, embryonic forms.^[38][39] The genre is most commonly found in Native American cultures where the myths frequently link the final emergence of people from a hole opening to the underworld to stories about their subsequent migrations and eventual settlement in their current homelands.^[40]

Earth-diver

The earth-diver is a common character in various traditional creation myths. In these stories a supreme being usually sends an animal into the primal waters to find bits of sand or mud with which to build habitable land. Some scholars interpret these myths psychologically while others interpret them cosmogonically. In both cases emphasis is placed on beginnings emanating from the depths.^[41] Earth-diver myths are common in Native American folklore but can be found among the Chukchi and Yukaghir, the Tatars and many Finno-Ugrian traditions. The pattern of distribution of these stories suggest they have a common origin in the eastern Asiatic coastal region, spreading as peoples migrated west into Siberia and east to the North American continent.^[42][43]

Characteristic of many Native American myths, earth-diver creation stories begin as beings and potential forms linger asleep or suspended in the primordial realm. The earth-diver is among the first of them to awaken and lay the necessary groundwork by building suitable lands where the coming creation will be able to live. In many cases, these stories will describe a series of failed attempts to make land before the solution is found.