Mind

From Wikipedia, the free encyclopedia

A phrenological mapping^[1] of the brain. Phrenology was among the first attempts to correlate mental functions with specific parts of the brain.

René Descartes' illustration of mind/body dualism. Descartes believed inputs are passed on by the sensory organs to the epiphysis in the brain and from there to the immaterial spirit.^[2]

A mind /ˈmaɪnd/ is the set of cognitive faculties that enables consciousness, perception, thinking, judgement, and memory—a characteristic of humans, but which also may apply to other life forms.^[3][4]

A lengthy tradition of inquiries in philosophy, religion, psychology and cognitive science has sought to develop an understanding of what a mind is and what its distinguishing properties are. The main question regarding the nature of mind is its relation to the physical brain and nervous system – a question which is often framed as the Mind-body problem, which considers whether mind is somehow separate from physical existence (dualism and idealism^[5]), deriving from and/or reducible to physical phenomena such as neuronal activity (physicalism), or whether the mind is identical with the brain or some activity of the brain.^[6] Another question concerns which types of beings are capable of having minds, for example whether mind is exclusive to humans, possessed also by some or all animals, by all living things, or whether mind can also be a property of some types of man-made machines.

Whatever its relation to the physical body it is generally agreed that mind is that which enables a being to have subjective awareness and intentionality towards their environment, to perceive and respond to stimuli with some kind of agency, and to have consciousness, including thinking and feeling.^[3][7]

Important philosophers of mind include Mulla Sadra, Plato, Descartes, Leibniz, Kant, Martin Heidegger, John Searle, Daniel Dennett and many others. The description and definition is also a part of psychology where psychologists such as Sigmund Freud and William James have developed influential theories about the nature of the human mind. In the late 20th and early 21st centuries the field of cognitive science emerged and developed many varied approaches to the description of mind and its related phenomena. The possibility of non-human minds is also explored in the field of artificial intelligence, which works closely in relation with cybernetics and information theory to understand the ways in which human mental phenomena can be replicated by nonbiological machines.

The concept of mind is understood in many different ways by many different cultural and religious traditions. Some see mind as a property exclusive to humans whereas others ascribe properties of mind to non-living entities (e.g. panpsychism and animism), to animals and to deities. Some of the earliest recorded speculations linked mind (sometimes described as identical with soul or spirit) to theories concerning both life after death, and cosmological and natural order, for example in the doctrines of Zoroaster, the Buddha, Plato, Aristotle, and other ancient Greek, Indian and, later, Islamic and medieval European philosophers.

Etymology

The original meaning of Old English gemynd was the faculty of memory, not of thought in general. Hence call to mind, come to mind, keep in mind, to have mind of, etc. The word retains this sense in Scotland. Old English had other words to express "mind", such as hyge "mind, spirit".

The meaning of "memory" is shared with Old Norse, which has munr. The word is originally from a PIE verbal root *men-, meaning "to think, remember", whence also Latin mens "mind", Sanskrit manas "mind" and Greek μένος "mind, courage, anger".

The generalization of mind to include all mental faculties, thought, volition, feeling and memory, gradually develops over the 14th and 15th centuries.^[8]

Definitions

The attributes that make up the mind is debated. Some psychologists argue that only the "higher" intellectual functions constitute mind, particularly reason and memory. In this view the emotions — love, hate, fear, joy — are more primitive or subjective in nature and should be seen as different from the mind as such. Others argue that various rational and emotional states cannot be so separated, that they are of the same nature and origin, and should therefore be considered all part of what we call the mind.

In popular usage, mind is frequently synonymous with thought: the private conversation with ourselves that we carry on "inside our heads." Thus we "make up our minds," "change our minds" or are "of two minds" about something. One of the key attributes of the mind in this sense is that it is a private sphere to which no one but the owner has access. No one else can "know our mind." They can only interpret what we consciously or unconsciously communicate.

Mental faculties

Broadly speaking, mental faculties are the various functions of the mind, or things the mind can "do".
Thought is a mental act that allows humans to make sense of things in the world, and to represent and interpret them in ways that are significant, or which accord with their needs, attachments, goals, commitments, plans, ends, desires, etc. Thinking involves the symbolic or semiotic mediation of ideas or data, as when we form concepts, engage in problem solving, reasoning and making decisions. Words that refer to similar concepts and processes include deliberation, cognition, ideation, discourse and imagination.

Thinking is sometimes described as a "higher" cognitive function and the analysis of thinking processes is a part of cognitive psychology. It is also deeply connected with our capacity to make and use tools; to understand cause and effect; to recognize patterns of significance; to comprehend and disclose unique contexts of experience or activity; and to respond to the world in a meaningful way.

Memory is the ability to preserve, retain, and subsequently recall, knowledge, information or experience. Although memory has traditionally been a persistent theme in philosophy, the late nineteenth and early twentieth centuries also saw the study of memory emerge as a subject of inquiry within the paradigms of cognitive psychology. In recent decades, it has become one of the pillars of a new branch of science called cognitive neuroscience, a marriage between cognitive psychology and neuroscience.

Imagination is the activity of generating or evoking novel situations, images, ideas or other qualia in the mind. It is a characteristically subjective activity, rather than a direct or passive experience. The term is technically used in psychology for the process of reviving in the mind percepts of objects formerly given in sense perception. Since this use of the term conflicts with that of ordinary language, some psychologists have preferred to describe this process as "imaging" or "imagery" or to speak of it as "reproductive" as opposed to "productive" or "constructive" imagination. Things imagined are said to be seen in the "mind's eye". Among the many practical functions of imagination are the ability to project possible futures (or histories), to "see" things from another's perspective, and to change the way something is perceived, including to make decisions to respond to, or enact, what is imagined.

Consciousness in mammals (this includes humans) is an aspect of the mind generally thought to comprise qualities such as subjectivity, sentience, and the ability to perceive the relationship between oneself and one's environment. It is a subject of much research in philosophy of mind, psychology, neuroscience, and cognitive science. Some philosophers divide consciousness into phenomenal consciousness, which is subjective experience itself, and access consciousness, which refers to the global availability of information to processing systems in the brain.^[9] Phenomenal consciousness has many different experienced qualities, often referred to as qualia. Phenomenal consciousness is usually consciousness of something or about something, a property known as intentionality in philosophy of mind.

Mental content

Mental contents are those items that are thought of as being "in" the mind, and capable of being formed and manipulated by mental processes and faculties. Examples include thoughts, concepts, memories, emotions, percepts and intentions. Philosophical theories of mental content include internalism, externalism, representationalism and intentionality.

Memetics

Memetics is a theory of mental content based on an analogy with Darwinian evolution, which was originated by Richard Dawkins and Douglas Hofstadter in the 1980s. It is an evolutionary model of cultural information transfer. A meme, analogous to a gene, is an idea, belief, pattern of behaviour (etc.) "hosted" in one or more individual minds, and can reproduce itself from mind to mind. Thus what would otherwise be regarded as one individual influencing another to adopt a belief, is seen memetically as a meme reproducing itself.

Relation to the brain

In animals, the brain, or encephalon (Greek for "in the head"), is the control center of the central nervous system, responsible for thought. In most animals, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, equilibrioception, taste and olfaction. While all vertebrates have a brain, most invertebrates have either a centralized brain or collections of individual ganglia. Primitive animals such as sponges do not have a brain at all. Brains can be extremely complex. For example, the human brain contains around 86 billion neurons, each linked to as many as 10,000 others.^[10][11]
Understanding the relationship between the brain and the mind – mind-body problem is one of the central issues in the history of philosophy – is a challenging problem both philosophically and scientifically.^[12] There are three major philosophical schools of thought concerning the answer: dualism, materialism, and idealism. Dualism holds that the mind exists independently of the brain;^[13] materialism holds that mental phenomena are identical to neuronal phenomena;^[14] and idealism holds that only mental phenomena exist.^[14]

Through most of history many philosophers found it inconceivable that cognition could be implemented by a physical substance such as brain tissue (that is neurons and synapses).^[15] Descartes, who thought extensively about mind-brain relationships, found it possible to explain reflexes and other simple behaviors in mechanistic terms, although he did not believe that complex thought, and language in particular, could be explained by reference to the physical brain alone.^[16]

The most straightforward scientific evidence of a strong relationship between the physical brain matter and the mind is the impact physical alterations to the brain have on the mind, such as with traumatic brain injury and psychoactive drug use.^[17] Philosopher Patricia Churchland notes that this drug-mind interaction indicates an intimate connection between the brain and the mind.^[18]

In addition to the philosophical questions, the relationship between mind and brain involves a number of scientific questions, including understanding the relationship between mental activity and brain activity, the exact mechanisms by which drugs influence cognition, and the neural correlates of consciousness.

Evolutionary history of the human mind

The evolution of human intelligence refers to a set of theories that attempt to explain how human intelligence has evolved. The question is closely tied to the evolution of the human brain, and to the emergence of human language.
The timeline of human evolution spans some 7 million years, from the separation of the Pan genus until the emergence of behavioral modernity by 50,000 years ago. Of this timeline, the first 3 million years concern Sahelanthropus, the following 2 million concern Australopithecus, while the final 2 million span the history of actual human species (the Paleolithic).

Many traits of human intelligence, such as empathy, theory of mind, mourning, ritual, and the use of symbols and tools, are already apparent in great apes although in lesser sophistication than in humans.

There is a debate between supporters of the idea of a sudden emergence of intelligence, or "Great leap forward" and those of a gradual or continuum hypothesis.

Theories of the evolution of intelligence include:

• Robin Dunbar's social brain hypothesis^[19]
• Geoffrey Miller's sexual selection hypothesis^[20]
• The ecological dominance-social competition (EDSC)^[21] explained by Mark V. Flinn, David C. Geary and Carol V. Ward based mainly on work by Richard D. Alexander.
• The idea of intelligence as a signal of good health and resistance to disease.
• The Group selection theory contends that organism characteristics that provide benefits to a group (clan, tribe, or larger population) can evolve despite individual disadvantages such as those cited above.
• The idea that intelligence is connected with nutrition, and thereby with status^[22] A higher IQ could be a signal that an individual comes from and lives in a physical and social environment where nutrition levels are high, and vice versa.

Philosophy of mind

Philosophy of mind is the branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body. The mind-body problem, i.e. the relationship of the mind to the body, is commonly seen as the central issue in philosophy of mind, although there are other issues concerning the nature of the mind that do not involve its relation to the physical body.^[23] José Manuel Rodriguez Delgado writes, "In present popular usage, soul and mind are not clearly differentiated and some people, more or less consciously, still feel that the soul, and perhaps the mind, may enter or leave the body as independent entities."^[24]
Dualism and monism are the two major schools of thought that attempt to resolve the mind-body problem. Dualism is the position that mind and body are in some way separate from each other. It can be traced back to Plato,^[25] Aristotle^[26][27][28] and the Samkhya and Yoga schools of Hindu philosophy,^[29] but it was most precisely formulated by René Descartes in the 17th century.^[30] Substance dualists argue that the mind is an independently existing substance, whereas Property dualists maintain that the mind is a group of independent properties that emerge from and cannot be reduced to the brain, but that it is not a distinct substance.^[31]

The 20th century philosopher Martin Heidegger suggested that subjective experience and activity (i.e. the "mind") cannot be made sense of in terms of Cartesian "substances" that bear "properties" at all (whether the mind itself is thought of as a distinct, separate kind of substance or not). This is because the nature of subjective, qualitative experience is incoherent in terms of – or semantically incommensurable with the concept of – substances that bear properties. This is a fundamentally ontological argument.^[32]

The philosopher of cognitive science Daniel Dennett, for example, argues there is no such thing as a narrative center called the "mind", but that instead there is simply a collection of sensory inputs and outputs: different kinds of "software" running in parallel.^[33] Psychologist B.F. Skinner argued that the mind is an explanatory fiction that diverts attention from environmental causes of behavior;^[34] he considered the mind a "black box" and thought that mental processes may be better conceived of as forms of covert verbal behavior.^[35][36]

Mind/body perspectives

Monism is the position that mind and body are not physiologically and ontologically distinct kinds of entities. This view was first advocated in Western Philosophy by Parmenides in the 5th Century BC and was later espoused by the 17th Century rationalist Baruch Spinoza.^[37] According to Spinoza's dual-aspect theory, mind and body are two aspects of an underlying reality which he variously described as "Nature" or "God".

• Physicalists argue that only the entities postulated by physical theory exist, and that the mind will eventually be explained in terms of these entities as physical theory continues to evolve.
• Idealists maintain that the mind is all that exists and that the external world is either mental itself, or an illusion created by the mind.
• Neutral monists adhere to the position that perceived things in the world can be regarded as either physical or mental depending on whether one is interested in their relationship to other things in the world or their relationship to the perceiver. For example, a red spot on a wall is physical in its dependence on the wall and the pigment of which it is made, but it is mental in so far as its perceived redness depends on the workings of the visual system. Unlike dual-aspect theory, neutral monism does not posit a more fundamental substance of which mind and body are aspects.

The most common monisms in the 20th and 21st centuries have all been variations of physicalism; these positions include behaviorism, the type identity theory, anomalous monism and functionalism.^[38]

Many modern philosophers of mind adopt either a reductive or non-reductive physicalist position, maintaining in their different ways that the mind is not something separate from the body.^[38] These approaches have been particularly influential in the sciences, e.g. in the fields of sociobiology, computer science, evolutionary psychology and the various neurosciences.^{[39][40][41][42]} Other philosophers, however, adopt a non-physicalist position which challenges the notion that the mind is a purely physical construct.

• Reductive physicalists assert that all mental states and properties will eventually be explained by scientific accounts of physiological processes and states.^[43][44][45]
• Non-reductive physicalists argue that although the brain is all there is to the mind, the predicates and vocabulary used in mental descriptions and explanations are indispensable, and cannot be reduced to the language and lower-level explanations of physical science.^[46][47]

Continued progress in neuroscience has helped to clarify many of these issues, and its findings strongly support physicalists' assertions.^[48][49] Nevertheless our knowledge is incomplete, and modern philosophers of mind continue to discuss how subjective qualia and the intentional mental states can be naturally explained.^[50][51]

Scientific study

Simplified diagram of Spaun, a 2.5-million-neuron computational model of the brain. (A) The corresponding physical regions and connections of the human brain. (B) The mental architecture of Spaun.^[52]

Neuroscience

Neuroscience studies the nervous system, the physical basis of the mind. At the systems level, neuroscientists investigate how biological neural networks form and physiologically interact to produce mental functions and content such as reflexes, multisensory integration, motor coordination, circadian rhythms, emotional responses, learning, and memory. At a larger scale, efforts in computational neuroscience have developed large-scale models that simulate simple, functioning brains.^[52] As of 2012, such models include the thalamus, basal ganglia, prefrontal cortex, motor cortex, and occipital cortex, and consequentially simulated brains can learn, respond to visual stimuli, coordinate motor responses, form short-term memories, and learn to respond to patterns. Currently, researchers aim to program the hippocampus and limbic system, hypothetically imbuing the simulated mind with long-term memory and crude emotions.^[53]
By contrast, affective neuroscience studies the neural mechanisms of personality, emotion, and mood primarily through experimental tasks.

Cognitive Science

Cognitive science examines the mental functions that give rise to information processing, termed cognition. These include attention, memory, producing and understanding language, learning, reasoning, problem solving, and decision making. Cognitive science seeks to understand thinking "in terms of representational structures in the mind and computational procedures that operate on those structures".^[54]

Psychology

Psychology is the scientific study of human behavior, mental functioning, and experience. As both an academic and applied discipline, Psychology involves the scientific study of mental processes such as perception, cognition, emotion, personality, as well as environmental influences, such as social and cultural influences, and interpersonal relationships, in order to devise theories of human behavior. Psychology also refers to the application of such knowledge to various spheres of human activity, including problems of individuals' daily lives and the treatment of mental health problems.
Psychology differs from the other social sciences (e.g., anthropology, economics, political science, and sociology) due to its focus on experimentation at the scale of the individual, or individuals in small groups as opposed to large groups, institutions or societies. Historically, psychology differed from biology and neuroscience in that it was primarily concerned with mind rather than brain. Modern psychological science incorporates physiological and neurological processes into its conceptions of perception, cognition, behaviour, and mental disorders.

Mental health

By analogy with the health of the body, one can speak metaphorically of a state of health of the mind, or mental health. Merriam-Webster defines mental health as "A state of emotional and psychological well-being in which an individual is able to use his or her cognitive and emotional capabilities, function in society, and meet the ordinary demands of everyday life." According to the World Health Organization (WHO), there is no one "official" definition of mental health. Cultural differences, subjective assessments, and competing professional theories all affect how "mental health" is defined. In general, most experts agree that "mental health" and "mental illness" are not opposites. In other words, the absence of a recognized mental disorder is not necessarily an indicator of mental health.
One way to think about mental health is by looking at how effectively and successfully a person functions. Feeling capable and competent; being able to handle normal levels of stress, maintaining satisfying relationships, and leading an independent life; and being able to "bounce back," or recover from difficult situations, are all signs of mental health.

Psychotherapy is an interpersonal, relational intervention used by trained psychotherapists to aid clients in problems of living. This usually includes increasing individual sense of well-being and reducing subjective discomforting experience. Psychotherapists employ a range of techniques based on experiential relationship building, dialogue, communication and behavior change and that are designed to improve the mental health of a client or patient, or to improve group relationships (such as in a family). Most forms of psychotherapy use only spoken conversation, though some also use various other forms of communication such as the written word, art, drama, narrative story, or therapeutic touch. Psychotherapy occurs within a structured encounter between a trained therapist and client(s). Purposeful, theoretically based psychotherapy began in the 19th century with psychoanalysis; since then, scores of other approaches have been developed and continue to be created.

Non-human minds

Animal intelligence

Animal cognition, or cognitive ethology, is the title given to a modern approach to the mental capacities of animals. It has developed out of comparative psychology, but has also been strongly influenced by the approach of ethology, behavioral ecology, and evolutionary psychology. Much of what used to be considered under the title of "animal intelligence" is now thought of under this heading. Animal language acquisition, attempting to discern or understand the degree to which animal cognition can be revealed by linguistics-related study, has been controversial among cognitive linguists.

Artificial intelligence

Computer simulation of the branching architecture of the dendrites of pyramidal neurons.^[55]

In 1950 Alan M. Turing published "Computing machinery and intelligence" in Mind, in which he proposed that machines could be tested for intelligence using questions and answers. This process is now named the Turing Test. The term Artificial Intelligence (AI) was first used by John McCarthy who considered it to mean "the science and engineering of making intelligent machines".^[56] It can also refer to intelligence as exhibited by an artificial (man-made, non-natural, manufactured) entity. AI is studied in overlapping fields of computer science, psychology, neuroscience and engineering, dealing with intelligent behavior, learning and adaptation and usually developed using customized machines or computers.

Research in AI is concerned with producing machines to automate tasks requiring intelligent behavior. Examples include control, planning and scheduling, the ability to answer diagnostic and consumer questions, handwriting, natural language, speech and facial recognition. As such, the study of AI has also become an engineering discipline, focused on providing solutions to real life problems, knowledge mining, software applications, strategy games like computer chess and other video games. One of the biggest limitations of AI is in the domain of actual machine comprehension. Consequentially natural language understanding and connectionism (where behavior of neural networks is investigated) are areas of active research and development.

The debate about the nature of the mind is relevant to the development of artificial intelligence. If the mind is indeed a thing separate from or higher than the functioning of the brain, then hypothetically it would be much more difficult to recreate within a machine, if it were possible at all. If, on the other hand, the mind is no more than the aggregated functions of the brain, then it will be possible to create a machine with a recognisable mind (though possibly only with computers much different from today's), by simple virtue of the fact that such a machine already exists in the form of the human brain.

In religion

Many religions associate spiritual qualities to the human mind. These are often tightly connected to their mythology and afterlife.

The Indian philosopher-sage Sri Aurobindo attempted to unite the Eastern and Western psychological traditions with his integral psychology, as have many philosophers and New religious movements. Judaism teaches that "moach shalit al halev", the mind rules the heart. Humans can approach the Divine intellectually, through learning and behaving according to the Divine Will as enclothed in the Torah, and use that deep logical understanding to elicit and guide emotional arousal during prayer. Christianity has tended to see the mind as distinct from the soul (Greek nous) and sometimes further distinguished from the spirit. Western esoteric traditions sometimes refer to a mental body that exists on a plane other than the physical. Hinduism's various philosophical schools have debated whether the human soul (Sanskrit atman) is distinct from, or identical to, Brahman, the divine reality. Taoism sees the human being as contiguous with natural forces, and the mind as not separate from the body. Confucianism sees the mind, like the body, as inherently perfectible.

Buddhism

According to Buddhist philosopher Dharmakirti, the mind has two fundamental qualities: "clarity and cognizes". If something is not those two qualities, it cannot validly be called mind. "Clarity" refers to the fact that mind has no color, shape, size, location, weight, or any other physical characteristic, and "cognizes" that it functions to know or perceive objects.^[57] "Knowing" refers to the fact that mind is aware of the contents of experience, and that, in order to exist, mind must be cognizing an object. You cannot have a mind - whose function is to cognize an object - existing without cognizing an object.
Mind, in Buddhism, is also described as being "space-like" and "illusion-like". Mind is space-like in the sense that it is not physically obstructive. It has no qualities which would prevent it from existing. In Mahayana Buddhism, mind is illusion-like in the sense that it is empty of inherent existence. This does not mean it does not exist, it means that it exists in a manner that is counter to our ordinary way of misperceiving how phenomena exist, according to Buddhism. When the mind is itself cognized properly, without misperceiving its mode of existence, it appears to exist like an illusion. There is a big difference however between being "space and illusion" and being "space-like" and "illusion-like". Mind is not composed of space, it just shares some descriptive similarities to space. Mind is not an illusion, it just shares some descriptive qualities with illusions.

Buddhism posits that there is no inherent, unchanging identity (Inherent I, Inherent Me) or phenomena (Ultimate self, inherent self, Atman, Soul, Self-essence, Jiva, Ishvara, humanness essence, etc.) which is the experiencer of our experiences and the agent of our actions. In other words, human beings consist of merely a body and a mind, and nothing extra. Within the body there is no part or set of parts which is - by itself or themselves - the person. Similarly, within the mind there is no part or set of parts which are themselves "the person". A human being merely consists of five aggregates, or skandhas and nothing else.

In the same way, "mind" is what can be validly conceptually labelled onto our mere experience of clarity and knowing. There is something separate and apart from clarity and knowing which is "Awareness", in Buddhism. "Mind" is that part of experience the sixth sens door, which can be validly referred to as mind by the concept-term "mind". There is also not "objects out there, mind in here, and experience somewhere in-between". There is a third thing called "awareness" which exists being aware of the contents of mind and what mind cognizes. There are five senses (arising of mere experience: shapes, colors, the components of smell, components of taste, components of sound, components of touch) and mind as the sixth institution; this means, expressly, that there can be a third thing called "awareness" and a third thing called "experiencer who is aware of the experience". This awareness is deeply related to "no-self" because it does not judge the experience with craving or aversion.

Clearly, the experience arises and is known by mind, but there is a third thing calls Sathi what is the "real experiencer of the experience" that sits apart from the experience and which can be aware of the experience in 4 levels. (Maha Sathipatthana Sutta.)

1. Body
2. Sensations (Changes of the body mind.)
3. Mind,
4. Contents of the mind. (Changes of the body mind.)

To be aware of these four levels one needs to cultivate equanimity toward Craving and Aversion. This is Called Vipassana which is different from the way of reacting with Craving and Aversion. This is the state of being aware and eqanimous to the complete experience of here and now. This is the way of Buddhism, with regards to mind and the ultimate nature of minds (and persons).

Mortality of the mind

Due to the mind-body problem, a lot of interest and debate surrounds the question of what happens to one's conscious mind as one's body dies. During brain death all brain function permanently ceases, according to the current neuroscientific view which sees these processes as the physical basis of mental phenomena, the mind fails to survive brain death and ceases to exist. This permanent loss of consciousness after death is often called "eternal oblivion". The belief that some spiritual or incorporeal component (soul) exists and that it is preserved after death is described by the term "afterlife".

In pseudoscience

Parapsychology

Parapsychology is the scientific study of certain types of paranormal phenomena, or of phenomena which appear to be paranormal,^[58] for instance precognition, telekinesis and telepathy.

The term is based on the Greek para (beside/beyond), psyche (soul/mind), and logos (account/explanation) and was coined by psychologist Max Dessoir in or before 1889.^[59] J. B. Rhine later popularized "parapsychology" as a replacement for the earlier term "psychical research", during a shift in methodologies which brought experimental methods to the study of psychic phenomena.^[59] Parapsychology is controversial, with many scientists believing that psychic abilities have not been demonstrated to exist.^{[60][61][62][63][64]} The status of parapsychology as a science has also been disputed,^[65] with many scientists regarding the discipline as pseudoscience.^[66][67][68]

Human impact on the environment

From Wikipedia, the free encyclopedia

The ecosystem of public parks often includes humans feeding the wildlife.

Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments, biodiversity, and other resources.^[1][2] The term anthropogenic designates an effect or object resulting from human activity. The term was first used in the technical sense by Russian geologist Alexey Pavlov, and was first used in English by British ecologist Arthur Tansley in reference to human influences on climax plant communities.^[3] The atmospheric scientist Paul Crutzen introduced the term "anthropocene" in the mid-1970s.^[4] The term is sometimes used in the context of pollution emissions that are produced as a result of human activities but applies broadly to all major human impacts on the environment.^[5]

Causes

Technology

The applications of technology (in general) often result in unavoidable environmental impacts, which according to the I=PAT equation is measured as resource use or pollution generated per unit GDP. Environmental impacts caused by the application of technology are often perceived as unavoidable for several reasons. First, given that the purpose of many technologies is to exploit, control, or otherwise “improve” upon nature for the perceived benefit of humanity while at the same time the myriad of processes in nature have been optimized and are continually adjusted by evolution, any disturbance of these natural processes by technology is likely to result in negative environmental consequences.^[6] Second, the conservation of mass principle and the first law of thermodynamics (i.e., conservation of energy) dictate that whenever material resources or energy are moved around or manipulated by technology, environmental consequences are inescapable. Third, according to the second law of thermodynamics, order can be increased within a system (such as the human economy) only by increasing disorder or entropy outside the system (i.e., the environment). Thus, technologies can create “order” in the human economy (i.e., order as manifested in buildings, factories, transportation networks, communication systems, etc.) only at the expense of increasing “disorder” in the environment. According to a number of studies, increased entropy is likely to be correlated to negative environmental impacts.^{[7][8][9][10]}

Agriculture

The environmental impact of agriculture varies based on the wide variety of agricultural practices employed around the world.

Fishing

Fishing down the foodweb.

The environmental impact of fishing can be divided into issues that involve the availability of fish to be caught, such as overfishing, sustainable fisheries, and fisheries management; and issues that involve the impact of fishing on other elements of the environment, such as by-catch.

These conservation issues are part of marine conservation, and are addressed in fisheries science programs. There is a growing gap between how many fish are available to be caught and humanity’s desire to catch them, a problem that gets worse as the world population grows.

Similar to other environmental issues, there can be conflict between the fishermen who depend on fishing for their livelihoods and fishery scientists who realize that if future fish populations are to be sustainable then some fisheries must reduce or even close.^[11]

The journal Science published a four-year study in November 2006, which predicted that, at prevailing trends, the world would run out of wild-caught seafood in 2048. The scientists stated that the decline was a result of overfishing, pollution and other environmental factors that were reducing the population of fisheries at the same time as their ecosystems were being degraded. Yet again the analysis has met criticism as being fundamentally flawed, and many fishery management officials, industry representatives and scientists challenge the findings, although the debate continues. Many countries, such as Tonga, the United States, Australia and New Zealand, and international management bodies have taken steps to appropriately manage marine resources.^[12][13]

Irrigation

The environmental impact of irrigation includes the changes in quantity and quality of soil and water as a result of irrigation and the ensuing effects on natural and social conditions at the tail-end and downstream of the irrigation scheme.
The impacts stem from the changed hydrological conditions owing to the installation and operation of the scheme.

An irrigation scheme often draws water from the river and distributes it over the irrigated area. As a hydrological result it is found that:

• the downstream river discharge is reduced
• the evaporation in the scheme is increased
• the groundwater recharge in the scheme is increased
• the level of the water table rises
• the drainage flow is increased.

These may be called direct effects.

The effects thereof on soil and water quality are indirect and complex, Water logging and soil salination are part of these, whereas the subsequent impacts on natural, ecological and socio-economic conditions is very intricate.

Irrigation can also be done extracting groundwater by (tube)wells. As a hydrological result it is found that the level of the water descends. The effects may be water mining, land/soil subsidence, and, along the coast, saltwater intrusion.

Irrigation projects can have large benefits, but the negative side effects are often overlooked.^[14][15] Agricultural irrigation technologies such as high powered water pumps, dams, and pipelines are responsible for the large-scale depletion of fresh water resources such as aquifers, lakes, and rivers. Humans appropriate more than 50% of the planet’s fresh water, mostly for use in irrigation.^[16] As a result of this massive diversion of freshwater, lakes, rivers, and creeks are running dry, severely altering or stressing surrounding ecosystems, and contributing to the extinction of many aquatic species.^[17]

Topsoil loss

The industrialization of agriculture during the last 150 years, specifically the widespread use of fossil fuel powered farm machinery for plowing, has resulted in massive top soil loss. Soils are currently lost at the rate of inches per decade while it takes hundreds of years for one inch of new topsoil to form.^[18] In the United States, 90% of the cropland is losing topsoil at a rate faster than is being formed.^[19] Worldwide, about one third of arable land has been lost due to erosion.^[20]

Meat production

The environmental impact of meat production includes pollution and the use of resources such as fossil fuels, water, and land. According to a 2006 report by the Livestock, Environment and Development Initiative, the livestock industry is one of the largest contributors to environmental degradation worldwide, and modern practices of raising animals for food contributes on a "massive scale" to air and water pollution, land degradation, climate change, and loss of biodiversity. The initiative concluded that "the livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global."^[21] In 2006 FAO estimated that meat industry contributes 18% of all emissions of greenhouse gasses. This figure was challenged in 2009 by two World-Watch researchers who estimated a 51% minimum,^[22] however this paper has not been peer reviewed.^[23]
Animals that feed on grain need more water than grain crops.^[24] In tracking food animal production from the feed through to the dinner table, the inefficiencies of meat, milk and egg production range from a 4:1 energy input to protein output ratio up to 54:1.^[24] The result is that producing animal-based food is typically much less efficient than the harvesting of grains, vegetables, legumes, seeds and fruits for direct human consumption.^[24]

Relatedly, the production and consumption of meat and other animal products is associated with the clearing of rainforests, resource depletion, air and water pollution, land and economic inefficiency, species extinction, and other environmental harms.

The author of the influential 2006 Stern Review on climate change has stated "people will need to turn vegetarian if the world is to conquer climate change". This is due to emissions of methane (which is 23 times more potent of a greenhouse gas versus carbon dioxide) from cows and pigs via flatulence and eructation.^[25]

Palm oil

A village palm oil press "malaxeur" in Bandundu, Democratic Republic of the Congo

Palm oil, produced from the oil palm, is a basic source of income for many farmers in Southeast Asia, Central and West Africa, and Central America. It is locally used as a cooking oil, exported for use in many commercial food and personal care products and is converted into biofuel. It produces up to 10 times more oil per unit area as soyabeans, rapeseed or sunflowers. Oil palms produce 38% of vegetable oil output on 5% of the world’s vegetable-oil farmland.^[26] Palm oil is under increasing scrutiny in relation to its effects on the environment.

Energy industry

The environmental impact of energy harvesting and consumption is diverse. In recent years there has been a trend towards the increased commercialization of various renewable energy sources.
In the real world of consumption of fossil fuel resources which lead to global warming and climate change. However, little change is being made in many parts of the world. If the peak oil theory proves true, more explorations of viable alternative energy sources, could be more friendly to the environment.

Rapidly advancing technologies can achieve a transition of energy generation, water and waste management, and food production towards better environmental and energy usage practices using methods of systems ecology and industrial ecology.^[27][28]

Biodiesel

The environmental impact of biodiesel is diverse. It includes greenhouse gas emissions, pollution, biodegradation, biodegradation in aquatic environments, and carbonyl emissions.

Coal mining and burning

The environmental impact of coal mining and burning is diverse.^[29] Legislation passed by the US Congress in 1990 required the United States Environmental Protection Agency (EPA) to issue a plan to alleviate toxic pollution from coal-fired power plants. After delay and litigation, the EPA now has a court-imposed deadline of March 16, 2011, to issue its report.

Electricity generation

The environmental impact of electricity generation is significant because modern society uses large amounts of electrical power. This power is normally generated at power plants that convert some other kind of energy into electricity. Each such system has advantages and disadvantages, but many of them pose environmental concerns.

Nuclear power

The environmental impact of nuclear power results from the nuclear fuel cycle processes including mining, processing, transporting and storing fuel and radioactive fuel waste. Released radioisotopes pose a health danger to human populations, animals and plants as radioactive particles enter organisms through various transmission routes.Radiation is a carcinogen and causes numerous effects on living organisms and systems. The environmental impacts of nuclear power plant releases such as the Chernobyl disaster, the Fukushima Daiichi nuclear disaster and the Three Mile Island accident, among others, persist indefinitely. The radioactive decay rate of particles varies greatly, dependent upon the atomic properties of a particular isotope. Radioactive Plutonium-244 has a half-life of 80.8 million years, which indicates the time duration required for half of a given sample to decay.^[30]

Oil shale industry

Kiviõli Oil Shale Processing & Chemicals Plant in ida-Virumaa, Estonia

The environmental impact of the oil shale industry includes the consideration of issues such as land use, waste management, and water and air pollution caused by the extraction and processing of oil shale. Surface mining of oil shale deposits causes the usual environmental impacts of open-pit mining. In addition, the combustion and thermal processing generate waste material, which must be disposed of, and harmful atmospheric emissions, including carbon dioxide, a major greenhouse gas. Experimental in-situ conversion processes and carbon capture and storage technologies may reduce some of these concerns in future, but may raise others, such as the pollution of groundwater.^[31]

Petroleum

The environmental impact of petroleum is often negative because it is toxic to almost all forms of life. The possibility of climate change exists. Petroleum, commonly referred to as oil, is closely linked to virtually all aspects of present society, especially for transportation and heating for both homes and for commercial activities.

Reservoirs

The Wachusett Dam in Clinton, Massachusetts.

The environmental impact of reservoirs is coming under ever increasing scrutiny as the world demand for water and energy increases and the number and size of reservoirs increases.

Dams and the reservoirs can be used to supply drinking water, generate hydroelectric power, increasing the water supply for irrigation, provide recreational opportunities and to improve certain aspects of the environment. However, adverse environmental and sociological impacts have also been identified during and after many reservoir constructions. Although the impact varies greatly between different dams and reservoirs, common criticisms include preventing sea-run fish from reaching their historical mating grounds, less access to water downstream, and a smaller catch for fishing communities in the area. Advances in technology have provided solutions to many negative impacts of dams but these advances are often not viewed as worth investing in if not required by law or under the threat of fines. Whether reservoir projects are ultimately beneficial or detrimental—to both the environment and surrounding human populations— has been debated since the 1960s and probably long before that. In 1960 the construction of Llyn Celyn and the flooding of Capel Celyn provoked political uproar which continues to this day. More recently, the construction of Three Gorges Dam and other similar projects throughout Asia, Africa and Latin America have generated considerable environmental and political debate.

Wind power

Wind turbines in an agricultural setting.

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor. Wind powered electricity generation consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.^[32]

There are reports of bird and bat mortality at wind turbines, as there are around other artificial structures. The scale of the ecological impact may^[33] or may not^[34] be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs,^[35] affect the siting and operation of wind turbines.

There are conflicting reports about the effects of noise on people who live very close to a wind turbine.

Manufactured products

Cleaning agents

The environmental impact of cleaning agents is diverse. In recent years, measures have been taken to reduce these effects.

Nanotechnology

Nanotechnology's environmental impact can be split into two aspects: the potential for nanotechnological innovations to help improve the environment, and the possibly novel type of pollution that nanotechnological materials might cause if released into the environment. As nanotechnology is an emerging field, there is great debate regarding to what extent industrial and commercial use of nanomaterials will affect organisms and ecosystems.

Paint

The environmental impact of paint is diverse. Traditional painting materials and processes can have harmful effects on the environment, including those from the use of lead and other additives. Measures can be taken to reduce environmental impact, including accurately estimating paint quantities so that wastage is minimized, use of paints, coatings, painting accessories and techniques that are environmentally preferred. The United States Environmental Protection Agency guidelines and Green Star ratings are some of the standards that can be applied.

Paper

A pulp and paper mill in New Brunswick, Canada. Although pulp and paper manufacturing requires large amounts of energy, a portion of it comes from burning wood waste.

The environmental impact of paper is significant, which has led to changes in industry and behaviour at both business and personal levels. With the use of modern technology such as the printing press and the highly mechanised harvesting of wood, paper has become a cheap commodity. This has led to a high level of consumption and waste. With the rise in environmental awareness due to the lobbying by environmental organizations and with increased government regulation there is now a trend towards sustainability in the pulp and paper industry.

Pesticides

The environmental impact of pesticides is often greater than what is intended by those who use them. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including nontarget species, air, water, bottom sediments, and food.^[36] Pesticide contaminates land and water when it escapes from production sites and storage tanks, when it runs off from fields, when it is discarded, when it is sprayed aerially, and when it is sprayed into water to kill algae.^[37]
The amount of pesticide that migrates from the intended application area is influenced by the particular chemical's properties: its propensity for binding to soil, its vapor pressure, its water solubility, and its resistance to being broken down over time.^[38] Factors in the soil, such as its texture, its ability to retain water, and the amount of organic matter contained in it, also affect the amount of pesticide that will leave the area.^[38] Some pesticides contribute to global warming and the depletion of the ozone layer.^[39]

Pharmaceuticals and personal care products

The environmental impact of pharmaceuticals and personal care products (PPCPs) is largely speculative. PPCPs are substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. PPCPs have been detected in water bodies throughout the world. The effects of these chemicals on humans and the environment are not yet known, but to date there is no scientific evidence that they have an impact on human health.^[40]

Mining

Acid mine drainage in the Rio Tinto River.

The environmental impact of mining includes erosion, formation of sinkholes, loss of biodiversity, and contamination of soil, groundwater and surface water by chemicals from mining processes. In some cases, additional forest logging is done in the vicinity of mines to increase the available room for the storage of the created debris and soil.^[41] Besides creating environmental damage, the contamination resulting from leakage of chemicals also affect the health of the local population.^[42] Mining companies in some countries are required to follow environmental and rehabilitation codes, ensuring the area mined is returned to close to its original state. Some mining methods may have significant environmental and public health effects.

Transport

Interstate 10 and Interstate 45 near downtown Houston, Texas in the United States.

The environmental impact of transport is significant because it is a major user of energy, and burns most of the world's petroleum. This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through emission of carbon dioxide,^[43] for which transport is the fastest-growing emission sector.^[44] By subsector, road transport is the largest contributor to global warming.^[43]

Environmental regulations in developed countries have reduced the individual vehicles emission; however, this has been offset by an increase in the number of vehicles, and more use of each vehicle.^[43] Some pathways to reduced the carbon emissions of road vehicles considerably have been studied.^[45] Energy use and emissions vary largely between modes, causing environmentalists to call for a transition from air and road to rail and human-powered transport, and increase transport electrification and energy efficiency.

Other environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. By reducing transportation emissions globally, it is predicted that there will be significant positive effects on Earth's air quality, acid rain, smog and climate change.^[46]

The health impact of transport emissions is also of concern. A recent survey of the studies on the effect of traffic emissions on pregnancy outcomes has linked exposure to emissions to adverse effects on gestational duration and possibly also intrauterine growth.^[47]

Aviation

The environmental impact of aviation occurs because aircraft engines emit noise, particulates, and gases which contribute to climate change^[48][49] and global dimming.^[50] Despite emission reductions from automobiles and more fuel-efficient and less polluting turbofan and turboprop engines, the rapid growth of air travel in recent years contributes to an increase in total pollution attributable to aviation. In the EU, greenhouse gas emissions from aviation increased by 87% between 1990 and 2006.^[51] Among other factors leading to this phenomenon are the increasing number of hypermobile travellers^[52] and social factors that are making air travel commonplace, such as frequent flyer programs.^[52]
There is an ongoing debate about possible taxation of air travel and the inclusion of aviation in an emissions trading scheme, with a view to ensuring that the total external costs of aviation are taken into account.^[53]

Roads

The environmental impact of roads includes the local effects of highways (public roads) such as on noise, water pollution, habitat destruction/disturbance and local air quality; and the wider effects including climate change from vehicle emissions. The design, construction and management of roads, parking and other related facilities as well as the design and regulation of vehicles can change the impacts to varying degrees.

Shipping

The environmental impact of shipping includes greenhouse gas emissions and oil pollution. Carbon dioxide emissions from shipping is currently estimated at 4 to 5% of the global total, and estimated by the International Maritime Organisation (IMO) to rise by up to 72% by 2020 if no action is taken.^[54] There is also a potential for introducing invasive species into new areas through shipping, usually by attaching themselves to the ship's hull.
The First Intersessional Meeting of the IMO Working Group on Greenhouse Gas Emissions^[55] from Ships took place in Oslo, Norway on 23–27 June 2008. It was tasked with developing the technical basis for the reduction mechanisms that may form part of a future IMO regime to control greenhouse gas emissions from international shipping, and a draft of the actual reduction mechanisms themselves, for further consideration by IMO’s Marine Environment Protection Committee (MEPC).^[56]

War

An Agent Orange spray run, part of Operation Ranch Hand, during the Vietnam War by UC-123B Provider aircraft.

As well as the cost to human life and society, there is a significant environmental impact of war. Scorched earth methods during, or after war have been in use for much of recorded history but with modern technology war can cause a far greater devastation on the environment. Unexploded ordnance can render land unusable for further use or make access across it dangerous or fatal.

Effects

Biodiversity

Human impact on biodiversity is significant, humans have caused the extinction of many species, including the dodo and, potentially, large megafaunal species during the last ice age. Though most experts agree that human beings have accelerated the rate of species extinction, the exact degree of this impact is unknown, perhaps 100 to 1000 times the normal background rate of extinction.^[57][58] Some authors have postulated that without human interference the biodiversity of this planet would continue to grow at an exponential rate.^[1]

Coral reefs

Human impact on coral reefs is significant. Coral reefs are dying around the world.^[59] In particular, coral mining, pollution (organic and non-organic), overfishing, blast fishing and the digging of canals and access into islands and bays are serious threats to these ecosystems. Coral reefs also face high dangers from pollution, diseases, destructive fishing practices and warming oceans.^[60] In order to find answers for these problems, researchers study the various factors that impact reefs. The list of factors is long, including the ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, biological virus, impacts of dust storms carrying agents to far flung reefs, pollutants, algal blooms and others. Reefs are threatened well beyond coastal areas.
General estimates show approximately 10% world's coral reefs are already dead.^[61][62][63] It is estimated that about 60% of the world's reefs are at risk due to destructive, human-related activities. The threat to the health of reefs is particularly strong in Southeast Asia, where 80% of reefs are endangered.

Carbon cycle

Global warming is the result of increasing atmospheric carbon dioxide concentrations which is caused primarily by the combustion of fossil energy sources such as petroleum, coal, and natural gas, and to an unknown extent by destruction of forests, increased methane (post-industria1: 150%), volcanic activity and cement production. Such massive alteration of the global carbon cycle has only been possible because of the availability and deployment of advanced technologies, ranging in application from fossil fuel exploration, extraction, distribution, refining, and combustion in power plants and automobile engines. Potential negative environmental impacts caused by increasing atmospheric carbon dioxide concentrations are rising global air temperatures, altered hydrogeological cycles resulting in more frequent and severe droughts, storms, and floods, as well as sea level rise and ecosystem disruption.^[64]

Nitrogen cycle

Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation.^[65][66] As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N₂O) mole fractions have increased from a pre-industrial value of ~270 nmol/mol to ~319 nmol/mol in 2005.^[67] Human activities account for over one-third of N₂O emissions, most of which are due to the agricultural sector.^[67]