Consciousness after death is a common theme in
society
A society is a group of individuals involved in persistent social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. Socie ...
and
culture
Culture () is an umbrella term which encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups.Tyl ...
in the context of
life after death
The afterlife (also referred to as life after death) is a purported existence in which the essential part of an individual's identity or their stream of consciousness continues to live after the death of their physical body. The surviving ess ...
.
Scientific
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence for ...
research
Research is "creativity, creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular att ...
has established that the physiological functioning of the
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
, the cessation of which defines
brain death
Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some aut ...
, is closely connected to mental states. However, many believe in some form of
life after death
The afterlife (also referred to as life after death) is a purported existence in which the essential part of an individual's identity or their stream of consciousness continues to live after the death of their physical body. The surviving ess ...
, which is a feature of many
religion
Religion is usually defined as a social- cultural system of designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relates humanity to supernatural, ...
s.
Neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...
is a large interdisciplinary field founded on the
premise
A premise or premiss is a true or false statement that helps form the body of an argument, which logically leads to a true or false conclusion. A premise makes a declarative statement about its subject matter which enables a reader to either agre ...
that all of
behavior
Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as wel ...
and all of the
cognitive processes
Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
that constitute the mind have their origin in the structure and function of the
nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
, especially in the brain. According to this view, the mind can be regarded as a set of operations carried out by the brain.
Many lines of
evidence
Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field.
In epistemology, evidenc ...
support this view, for example:
* Neuroanatomical correlates: In the field of
neuroimaging
Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incre ...
,
neuroscientist
A neuroscientist (or neurobiologist) is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, Biological neural network, n ...
s can use various
functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions. It is primarily used a ...
methods to measure an aspect of brain function that correlates with a particular mental state or process.
* Experimental manipulations: Neuroimaging correlational studies cannot determine whether neural activity plays a causal role in the occurrence of mental processes (
correlation does not imply causation
The phrase "correlation does not imply causation" refers to the inability to legitimately deduce a cause-and-effect relationship between two events or variables solely on the basis of an observed association or correlation between them. The id ...
) and they cannot determine if the neural activity is either
necessary or sufficient for such processes to occur. Identification of
causation and necessary and sufficient conditions requires explicit
experimental manipulation of that activity. If manipulation of brain activity changes
consciousness
Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
, then a causal role for that brain activity can be
inferred
Inferences are steps in reasoning, moving from premises to logical consequences; etymologically, the word '' infer'' means to "carry forward". Inference is theoretically traditionally divided into deduction and induction, a distinction that i ...
.
Two of the most common types of manipulation experiments are loss-of-function and gain-of-function experiments. In a loss-of-function (also called "necessity") experiment, a part of the nervous system is diminished or removed in an attempt to determine if it is necessary for a certain process to occur, and in a gain-of-function (also called "sufficiency") experiment, an aspect of the nervous system is increased relative to normal. Manipulations of brain activity can be performed in several ways:
::Pharmacological manipulation uses various
drugs
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalat ...
which alter neural activity by interfering with
neurotransmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), ...
, resulting in alterations in
perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system ...
,
mood, consciousness, cognition, and behavior. Psychoactive drugs are divided into different groups according to their pharmacological effects;
euphoriants
Euphoria ( ) is the experience (or affect) of pleasure or excitement and intense feelings of well-being and happiness. Certain natural rewards and social activities, such as aerobic exercise, laughter, listening to or making music and danc ...
which tend to induce feelings of
euphoria
Euphoria ( ) is the experience (or affect) of pleasure or excitement and intense feelings of well-being and happiness. Certain natural rewards and social activities, such as aerobic exercise, laughter, listening to or making music and da ...
,
stimulant
Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drugs including those that increase activity of the central nervous system and the body, drugs that are pleasurable and inv ...
s that induce temporary improvements in either mental or physical functions,
depressant
A depressant, or central depressant, is a drug that lowers neurotransmission levels, which is to depress or reduce arousal or stimulation, in various areas of the brain. Depressants are also colloquially referred to as downers as they lower the ...
s that depress or reduce arousal or stimulation and
hallucinogen
Hallucinogens are a large, diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes. Most hallucinogens can be categorized ...
s which can cause
hallucinations
A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...
, perception anomalies, and other substantial subjective changes in thoughts, emotion, and consciousness.
::Electrical and magnetical stimulations uses various
electrical methods and techniques like
transcranial magnetic stimulation
Transcranial magnetic stimulation (TMS) is a noninvasive form of brain stimulation in which a changing magnetic field is used to induce an electric current at a specific area of the brain through electromagnetic induction. An electric pulse gener ...
. In a comprehensive review of electrical brain stimulation (EBS) results obtained from the last 100 years neuroscientist Aslihan Selimbeyoglu and neurologist Josef Parvizi compiled a list of many different subjective experiential phenomena and behavioral changes that can be caused by electrical stimulation of the cerebral cortex or subcortical nuclei in awake and conscious human subjects.
::
Optogenetic
Optogenetics is a biological technique to control the activity of neurons or other cell types with light. This is achieved by expression of light-sensitive ion channels, pumps or enzymes specifically in the target cells. On the level of individ ...
manipulation uses light to control neurons which have been genetically sensitised to light.
*
Symptoms of brain damage: Examining case studies (like the case of
Phineas Gage
Phineas P. Gage (18231860) was an American railroad construction foreman known for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and ...
) and
lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals.
Types
There is no designated classifi ...
studies are the only sources of knowledge regarding what happens to the mind when the brain is damaged. Various symptoms have been documented.
*
Mental development
The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The fiel ...
/
brain development
The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The fiel ...
correlation: The brain grows and develops in an intricately orchestrated sequence of stages, and this development is correlated with the development of various mental capabilities. Impairments in the growth and development of the brain also result in various
neurodevelopmental disorder
Neurodevelopmental disorders are a group of disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. The effects of neurodevelopmental ...
s.
Death
Death is the permanent end of all
biological functions that sustain a living
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
. It is no longer defined as the cessation of
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
beat (
cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
) and
breath
Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.
All aerobic creatures need oxygen for cellular ...
ing, as
CPR
Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore sponta ...
and prompt
defibrillation
Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''cou ...
can sometimes restart both.
In modern medicine, when a definition of the moment of death is required, doctors and coroners usually turn to "brain death" or "biological death" to define a person as being dead; brain death being defined as the complete and irreversible loss of brain function (including involuntary activity necessary to sustain life).
Near-death experience (NDE)
A near-death experience (NDE) is a personal experience associated with impending
death
Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
, encompassing multiple possible sensations. Some explanations from neuroscience hypothesize the NDE to be a
hallucinatory state caused by various neurological factors such as
cerebral anoxia
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in o ...
,
hypercarbia
Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous pr ...
, abnormal activity in the
temporal lobe
The temporal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The temporal lobe ...
s and
brain damage
Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating t ...
, though the exact nature of such experiences is not universally agreed upon.
[Elizabeth Kübler Ross, Questions and Answers on Death and Dying: A Memoir of Living and Dying, Macmillan, 1976. .]
See also
*
Biogerontology
Biogerontology is the sub-field of gerontology concerned with the biological aging process, its evolutionary origins, and potential means to intervene in the process. The term "biogerontology" was coined by S. Rattan, and came in regular use wit ...
, the science of biological aging
*
Death anxiety
Death anxiety is anxiety caused by thoughts of one's own death, and is also referred to as thanatophobia (fear of death). Death anxiety differs from necrophobia, which is the fear of others who are dead or dying.
Psychotherapist Robert Langs ...
*
Disorders of consciousness
Disorders of consciousness are medical conditions that inhibit consciousness. Some define disorders of consciousness as any change from complete self-awareness to inhibited or absent self-awareness and arousal. This category generally includes min ...
, including brain death
*
Dualism (philosophy of mind)
Dualism most commonly refers to:
* Mind–body dualism, a philosophical view which holds that mental phenomena are, at least in certain respects, not physical phenomena, or that the mind and the body are distinct and separable from one another
** ...
*
Eternal oblivion
Eternal oblivion (also referred to as non-existence or nothingness) is the philosophical or religious concept of one's consciousness forever ceasing upon death. Pamela Health and Jon Klimo write that this concept is mostly associated with religio ...
*
Information-theoretic death
Information-theoretic death is a term of art used in cryonics to define death in a way that is permanent and independent of any future medical advances, no matter how distant or improbable that may be. Because detailed reading or restoration of in ...
*
Life extension
Life extension is the concept of extending the human life expectancy, lifespan, either modestly through improvements in medicine or dramatically by increasing the maximum lifespan beyond its generally-settled oldest people, limit of 125 years.
S ...
*
Neural correlates of consciousness
The neural correlates of consciousness (NCC) refer to the relationships between mental states and neural states and constitute the minimal set of neuronal events and mechanisms sufficient for a specific conscious percept. Neuroscientists use empi ...
*
Self
The self is an individual as the object of that individual’s own reflective consciousness. Since the ''self'' is a reference by a subject to the same subject, this reference is necessarily subjective. The sense of having a self—or ''selfhood ...
*
Senescence
Senescence () or biological aging is the gradual deterioration of functional characteristics in living organisms. The word ''senescence'' can refer to either cellular senescence or to senescence of the whole organism. Organismal senescence inv ...
, biological aging
*
Unconsciousness
Unconsciousness is a state in which a living individual exhibits a complete, or near-complete, inability to maintain an consciousness, awareness of self and environment or to respond to any human or environmental Stimulus (physiology), stimulus. ...
References
Further reading
*
Martin, Michael; Augustine, Keith. (2015)
''The Myth of an Afterlife: The Case against Life After Death'' Rowman & Littlefield.
*
Laureys, Steven;
Tononi, Giulio. (2009). ''The Neurology of Consciousness: Cognitive Neuroscience and Neuropathology''. Academic Press.
"What Happens to Consciousness When We Die" ''
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
''.
{{death
Afterlife
Consciousness
Consciousness studies
Death
Philosophy of mind
Neuroscience