Human

? Human Conservation status: Secure
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Superfamily: Hominoidea Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens
Binomial name
Homo sapiens Linnaeus, 1758
Subspecies
Homo sapiens idaltu (extinct) Homo sapiens sapiens

Human beings define themselves in biological, social, and spiritual terms. Biologically, humans are classified as the species Homo sapiens ( Latin for "wise man"): a bipedal primate of the superfamily Hominoidea, together with the other apes—chimpanzees, gorillas, orangutans, and gibbons.

Humans have an erect body carriage that frees their upper limbs for manipulating objects, and a highly developed brain capable of abstract reasoning, speech, language, and introspection. Bipedal locomotion appears to have evolved before the development of a large brain. The origins of bipedal locomotion and of its role in the evolution of the human brain are topics of ongoing research.

The human mind has several distinct attributes. It is responsible for complex behaviour, especially language. Curiosity and observation have led to a variety of explanations for consciousness and the relation between mind and body. Psychology attempts to study behaviour from a scientific point of view. Religious perspectives emphasise a soul, qi or atman as the essence of being, and are often characterised by the belief in and worship of God, gods or spirits. Philosophy, especially philosophy of mind, attempts to fathom the depths of each of these perspectives. Art, music and literature are often used in expressing these concepts and feelings.

Like all primates, humans are inherently social. They create complex social structures composed of co-operating and competing groups. These range from nations and states down to families, and from the community to the self. Seeking to understand and manipulate the world around them has led to the development of technology and science. Artifacts, beliefs, myths, rituals, values, and social norms have each played a role in forming humanity's culture.

Terminology

In general, the word "people" is a collective noun used to define a specific group of humans. However, when used to refer to a group of humans possessing a common ethnic, cultural or national unitary characteristic or identity, "people" is a singular noun, and as such takes an "s" in the plural; (examples: "the English-speaking peoples of the world", "the indigenous peoples of Brazil").

Juvenile males are called boys, adult males men, juvenile females girls, and adult females women. Humans are commonly referred to as persons or people, and collectively as Man (capital M), mankind, humankind, humanity, or the human race. Until the 20th century, "human" was only used adjectivally ("pertaining to mankind"). As an adjective, "human" is used neutrally (as in "human race"), but "human" and especially "humane" may also emphasize positive aspects of human nature, and can be synonymous with "benevolent" (versus "inhumane"; cf. humanitarian).

A distinction is maintained in philosophy and law between the notions "human being", or "man", and "person". The former refers to the species, while the latter refers to a rational agent (see, for example, John Locke's Essay concerning Human Understanding II 27 and Immanuel Kant's Introduction to the Metaphysic of Morals).

Biology

Anatomy and physiology

Human body types vary substantially, with some of this variation being caused by environmental and historical factors. Although body size is largely determined by genes, it is also significantly influenced by diet and exercise. The average height of a North American adult female is 162 centimetres (5 feet 4 inches), and the average weight is 62 kilograms (137 pounds). Human males are typically larger than females: the average height and weight of a North American adult male is 175 centimetres (5 feet 9 inches) and 78 kilograms (172 pounds).

Although humans appear relatively hairless compared to that of other primates, with notable hair growth occurring chiefly on the top of the head, underarms and pubic area, the average human has more hair on its body than the average chimpanzee. The main distinction is that human hairs are shorter, finer, and less coloured than the average chimpanzee's, thus making them harder to see.

The colour of human hair and skin is determined by the presence of pigments called melanins. Human skin colour can range from very dark brown to very pale pink, while human hair ranges from blond to brown to red. Most researchers believe that skin darkening was an adaptation that evolved as a defence against ultraviolet solar radiation: melanin is an effective sunblock. The skin colour of contemporary humans is geographically stratified, and in general correlates with the level of ultraviolet radiation. Human skin and hair colour is controlled in part by the genes Mc1r and SLC24A5. For example, the red hair and pale skin of some Europeans is the result of mutations in Mc1r. Human skin has a capacity to darken ( sun tanning) in response to exposure to ultraviolet radiation; this is also controlled in part by Mc1r.

Humans are capable of fully bipedal locomotion, thus leaving the arms available for manipulating objects using their hands, aided especially by opposable thumbs. Because human physiology has not fully adapted to bipedalism, the pelvic region and spinal column tend to become worn, creating locomotion difficulties in old age.

The need for regular intake of food and drink is prominently reflected in human culture, and has led to the development of food science. Failure to obtain food leads to hunger and eventually starvation, while failure to obtain water leads to thirst and dehydration. Both starvation and dehydration cause death if not alleviated -- generally, most humans can survive for over two months without food, but at most between ten to fourteen days without water. In modern times, obesity amongst some human populations has increased to almost epidemic proportions, leading to health complications and increased mortality in some developed countries, and is becoming problematic elsewhere.

The average sleep requirement is between seven and eight hours a day for an adult and nine to ten hours for a child (elderly people usually sleep for six to seven hours). Negative effects result from restriction of sleep. For instance a sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including fatigue, aggression, and bodily discomfort. It is common in modern societies for people to get less sleep than they need, leading to a state of sleep deprivation.

Life cycle

The human life cycle is similar to that of other placental mammals. New human life develops viviparously from conception. An egg is usually fertilised inside the female by sperm from the male through sexual intercourse, though in vitro fertilisation methods are also used. The fertilised egg is called a zygote. The zygote divides inside the female's uterus to become an embryo which over a period of thirty-eight weeks becomes the fetus. At birth, the fully grown fetus is expelled from the female's body and breathes independently as a baby for the first time. At this point, most modern cultures recognise the baby as a person entitled to the full protection of the law, though some jurisdictions extend personhood to human fetuses while they remain in the uterus.

Compared with that of other species, human childbirth is relatively complicated. Painful labours lasting twenty-four hours or more are not uncommon, and may result in injury to the child or the death of the mother, although the chances of a successful labour increased significantly during the twentieth century in wealthier countries. Natural childbirth remains a more dangerous ordeal in remote, underdeveloped regions of the world.

Human children are born after a nine-month gestation period, with typically 3–4 kilograms (6–9 pounds) in weight and 50–60 centimetres (20–24 inches) in height in developed countries. [1] Helpless at birth, they continue to grow for some years, typically reaching sexual maturity at twelve to fifteen years of age. Boys continue growing for some time after this, reaching their maximum height around the age of eighteen. These values vary too, depending on genes and environment.

The human lifespan can be split into a number of stages: infancy, childhood, adolescence, young adulthood, maturity and old age, although the lengths of these stages, especially the later ones, are not fixed.

There are striking differences in life expectancy around the world. The developed world is quickly getting older, with the median age around 40 years (highest in Monaco at 45.1 years), while in the developing world, the median age is 15–20 years (the lowest in Uganda at 14.8 years). Life expectancy at birth is 77.2 years in the U.S. as of 2001. [2] The expected life span at birth in Singapore is 84.29 years for a female and 78.96 years for a male, while in Botswana, due largely to AIDS, it is 30.99 years for a male and 30.53 years for a female. One in five Europeans, but one in twenty Africans, is 60 years or older, according to The World Factbook. [3]

The number of centenarians in the world was estimated by the United Nations [4] at 210,000 in 2002. The current maximum life span of humans is about 120 years ( Jeanne Calment lived for 122 years and 164 days). Worldwide, there are 81 men aged 60 or over for every 100 women of the same age, and among the oldest, there are 53 men for every 100 women.

The philosophical questions of when human personhood begins and whether it persists after death are the subject of considerable debate. The prospect of death may cause unease or fear. People who are near death sometimes report having a near-death experience, in which they have visions. Burial ceremonies are characteristic of human societies, often inspired by beliefs in an afterlife. Institutions of inheritance or ancestor worship may extend an individual's presence beyond his physical lifespan (see immortality).

Emotion and sexuality

Human emotion has a significant influence on, or can even be said to control, human behaviour. Emotional experiences perceived as pleasant, like love, admiration, or joy, contrast with those perceived as unpleasant, like hate, envy, or sorrow. There is often a distinction seen between refined emotions, which are socially learned, and survival oriented emotions, which are thought to be innate.

Human exploration of emotions as separate from other neurological phenomena is worth note, particularly in those cultures where emotion is considered separate from physiological state. In some cultural medical theories, to provide an example, emotion is considered so synonymous with certain forms of physical health that no difference is thought to exist. The Stoics believed excessive emotion was harmful, while some Sufi teachers (in particular, the poet and astronomer Omar Khayyám) felt certain extreme emotions could yield a conceptual perfection, what is often translated as ecstasy.

In modern scientific thought, certain refined emotions are considered to be a complex neural trait of many domesticated and a few non-domesticated mammals, developed commonly in reaction to superior survival mechanisms and intelligent interaction with each other and the environment; as such, refined emotion is not in all cases as discrete and separate from natural neural function as was once assumed. Still, when humans function in civilised tandem, it has been noted that uninhibited acting on extreme emotion can lead to social disorder and crime.

Human sexuality, besides ensuring reproduction, has important social functions, creating physical intimacy, bonds and hierarchies among individuals, and that may be directed to spiritual transcendence, and/or to the enjoyment of activity involving sexual gratification. Sexual desire, libido, is experienced as a bodily urge, often accompanied by strong emotions, both positive (such as love or ecstasy) and negative (such as jealousy).

As with other human self-descriptions, humans propose that it is high intelligence and complex societies of humans that have produced the most complex sexual behaviors of any animal, including a great many behaviors that are not directly connected with reproduction.

Human sexual choices are usually made in reference to cultural norms, which vary widely. Restrictions are largely determined by religious beliefs. Most sexologists, starting with the pioneers Alfred Kinsey and Sigmund Freud, believe (based upon the human species close relatives' sexual habits such as the bonobo apes, and historical records particularly the widespread ancient practices of paederasty) that the majority of homo sapiens are attracted to males and females, being inherently bisexual.

Genetics

Humans are a eukaryotic species. Each diploid cell has two sets of 23 chromosomes, each set received from one parent. There are 22 pairs of autosomes and one pair of sex chromosomes. At present estimate, humans have approximately 20,000–25,000 genes and share 98.4% of their DNA with their closest living evolutionary relatives, the two species of chimpanzees. [5] Like other mammals, humans have an XY sex determination system, so that females have the sex chromosomes XX and males have XY. The X chromosome is larger and carries many genes not on the Y chromosome, which means that recessive diseases associated with X-linked genes affect men more often than women. For example, genes that control the clotting of blood reside on the X chromosome. Women have a blood-clotting gene on each X chromosome so that one normal blood-clotting gene can compensate for a flaw in the gene on the other X chromosome. But men are hemizygous for the blood-clotting gene, since there is no gene on the Y chromosome to control blood clotting. As a result, men will suffer from haemophilia more often than women.

Race and ethnicity

Main articles: Race and Ethnic group

Humans often categorise themselves and others in terms of race or ethnicity, although the scientific validity of human races as categories is disputed. Human racial categories are based on visible traits, especially skin colour and facial features, language, and ancestry. Self identification with an ethnic group is based on kinship and descent. Race and ethnicity can lead to variant treatment and impact social identity, giving rise to the theory of identity politics. An ethnic group is a culture or subculture whose members are readily distinguishable by outsiders based on traits originating from a common racial, national, linguistic, regional or religious source.

Although most humans recognise that variances occur within a species, it is often a point of dispute as to what these differences entail, their importance, and whether discrimination based on race ( racism) is acceptable. Race and intelligence, scientific racism, xenophobia and ethnocentrism are just a few of the many bases for such practices.

Some societies have placed a great deal of emphasis on race, others have not. Four extremes include the " melting pot" of Ancient Egypt, the "colour blind" racial policy of contemporary France, slavery and Jim Crow laws being replaced by the Civil Rights Act in the United States, and the racial policy of Nazi Germany.

Habitat

The view most widely accepted by the anthropological community is that the human species originated in the African savanna between 100 and 200 thousand years ago, had colonised the rest of the Old World and Oceania by 40,000 years ago, and finally colonised the Americas by 10,000 years ago. Homo sapiens displaced groups such as Homo neanderthalensis, Homo erectus and Homo floresiensis through more successful reproduction and competition for resources. (See Human evolution, Vagina gentium, and Environment of Evolutionary Adaptedness.) Technology has allowed humans to colonise all of the continents and adapt to all climates. Within the last few decades, humans have explored Antarctica, the ocean depths, and space, although long-term habitation of these environments is not yet possible. Humans, with a population of over six billion, are one of the most numerous of the large mammals.

Most humans (61%) live in Asia. The vast majority of the remainder live in the Americas (14%), Africa (13%) and Europe (12%), with 5% in Oceania. (See list of countries by population and list of countries by population density.)

The original human lifestyle was hunting-gathering, which was adapted to the savanna. Other human lifestyles are nomadism (often linked to animal herding) and permanent settlements made possible by the development of agriculture. Humans have a great capacity for altering their habitats by various methods, such as agriculture, irrigation, urban planning, construction, transport, and manufacturing goods.

Permanent human settlements are dependent on proximity to water and, depending on the lifestyle, other natural resources such as fertile land for growing crops and grazing livestock, or seasonally by populations of prey. With the advent of large-scale trade and transport infrastructure, proximity to these resources has become unnecessary, and in many places these factors are no longer a driving force behind growth and decline of population.

Human habitation within closed ecological systems in hostile environments (Antarctica, outer space) is expensive, typically limited in duration, and restricted to scientific, military, or industrial expeditions. Life in space has been very sporadic, with a maximum of thirteen humans in space at any given time. Between 1969 and 1972, two humans at a time spent brief intervals on the Moon. As of 2005, no other celestial body has been visited by human beings, although there has been a continuous human presence in space since the launch of the initial crew to inhabit the International Space Station on October 31, 2000.

Food and drink

Humans are omnivorous animals who can consume both plant and animal products. Evidence shows that early Homo Sapiens employed a Hunter-gatherer methodology as their primary means of food collection. This involved combining stationary plant and fungal food sources (such as fruits, grains, tubers, and mushrooms) with wild game which must be hunted and killed in order to be consumed. However, many modern humans choose to be vegans or vegetarians. Additionally, it is believed that humans have used fire to prepare food prior to eating since the time of their divergence from Homo erectus, possibly even earlier.

At least ten thousand years ago, humans developed agriculture, which has altered substantially the kind of food people eat. This has led to a variety of important historical consequences, such as increased population, the development of cities, and, due to increased population density, the wider spread of infectious diseases. The types of food consumed, and the way in which they are prepared has varied widely by time, location, and culture.

The last century or so has produced enormous improvements in food production, preservation, storage and shipping. Today almost every locale in the world has access to not only its traditional cuisine, but also to many other world cuisines.

Population

From 1800 to 2000, the human population increased from one to six billion. In 2004, around 2.5 billion out of 6.3 billion people lived in urban areas, and this is expected to rise throughout the 21st century. Problems for humans living in cities include various forms of pollution, crime, and poverty, especially in inner city and suburban slums.

Evolution

Main articles: Human evolution and Human migration

The study of human evolution encompasses many scientific disciplines, but most notably physical anthropology and genetics. The term "human", in the context of human evolution, refers to the genus Homo, but studies of human evolution usually include other hominids and hominines, such as the australopithecines.

Humans are defined as hominids of the species Homo sapiens, of which the only extant subspecies is Homo sapiens sapiens (Latin for "very wise man"); Homo sapiens idaltu (roughly translated as "elderly wise man") is the extinct subspecies. Modern humans are usually considered the only surviving species in the genus Homo, although some argue that the two species of chimpanzees should be reclassified from Pan troglodytes (Common Chimpanzee) and Pan paniscus (Bonobo/Pygmy Chimpanzee) to Homo troglodytes and Homo paniscus respectively, given that they share a recent ancestor with man. [6]

Full genome sequencing resulted in these conclusions: "After 6 [million] years of separate evolution, the differences between chimp and human are just 10 times greater than those between two unrelated people and 10 times less than those between rats and mice." [ http://news.ft.com/cms/s/43445728-1a44-11da-b279-00000e2511c8.htmll Chimp and human DNA is 96% identical]

It has been estimated that the human lineage diverged from that of chimpanzees about five million years ago, and from gorillas about eight million years ago. However, in 2001 a hominid skull approximately seven million years old, classified as Sahelanthropus tchadensis, was discovered in Chad and may indicate an earlier divergence.

Two prominent scientific theories of the origins of contemporary humans exist. They concern the relationship between modern humans and other hominids:

• The single-origin or " out of Africa" hypothesis proposes that modern humans evolved in Africa and later replaced hominids in other parts of the world.

• The multiregional hypothesis proposes that modern humans evolved at least in part from independent hominid populations.

Geneticists Lynn Jorde and Henry Harpending of the University of Utah proposed that the variation in human DNA is minute compared to that of other species; and that during the Late Pleistocene, the population was reduced to a small number of breeding pairs (no more than 10,000), resulting in a very small residual gene pool. Various reasons for this possible bottleneck have been postulated, the most popular is called the Toba catastrophe theory.

Human evolution is characterised by a number of important physiological trends:

• expansion of the brain cavity and brain itself, which is typically 1,400 cm³ in volume, over twice that of a chimpanzee or gorilla. The pattern of human postnatal brain growth differs from that of other apes ( heterochrony), allowing for an extended period of social learning in juvenile humans. Physical anthropologists argue that a reorganisation of the structure of the brain is more important than cranial expansion itself;
• canine tooth reduction;
• bipedal locomotion;
• descent of the larynx and hyoid bone, making speech possible.

How these trends are related and what their role is in the evolution of complex social organisation and culture are matters of ongoing debate.

Intelligence

Human beings are considered more intelligent than other animals. While other animals are capable of creating structures (mostly as a result of instinct) and using simple tools, human technology is more complex, constantly evolving and improving with time. Even the most ancient human tools and structures are far more advanced than any structure or tool created by another animal.

The human ability to think abstractly may be unparalleled in the animal kingdom. Human beings are one of six species to pass the mirror test — which tests whether an animal recognises its reflection as an image of itself — along with common chimpanzees, bonobos, orangutans, dolphins and pigeons. Human beings under the age of 2 usually fail the test [7].

Culture

Main articles: Culture of human beings and Culture

Culture is defined here as a set of distinctive material, intellectual, emotional, and spiritual features of a social group, including art, literature, lifestyles, value systems, traditions, rituals, and beliefs.

Culture consists of at least three elements: values, social norms, and artifacts. A culture's values define what it holds to be important. Norms are expectations of how people ought to behave. Artifacts — things, or material culture — derive from the culture's values and norms together with its understanding of the way the world functions.

Origin Beliefs

Throughout their history humans have had many beliefs and theories surrounding their origin, and by extension that of the universe itself. Many of the oldest of these are related to religion and mythology, and express the belief that humans, the Earth and the universe were created by one or more deities or other supernatural entities. This may have been a creation out of nothing ( ex nihilo), or explained as the emergence of order from pre-existing chaos, often envisioned as an infinite ocean. Other common themes include the separation of mother and father gods, and a dead deity's body being used to create humanity and the world. In modern times, scientific observation and theory has provided other means for investigating the origin of humanity. The theory of evolution explains the emergence of humanity from earlier known species through the process of natural selection, whereas modern cosmology posits the universe as having been started in a period of rapid expansion known as the Big Bang. The impact and acceptance of these scientific theories, and their compatibility with earlier religious beliefs, continues to be a point of contention to some.

Language

Main articles: Language and Philosophy of language

Values, norms and technology are dependent on the capacity for humans to share ideas. The faculty of speech is a defining feature of humanity, possibly predating phylogenetic separation of the modern population. (See Origins of language.) Language is central to the communication between humans. Language is central to the sense of identity that unites cultures and ethnicities.

The invention of writing systems some 5000 years ago, allowing the preservation of speech, was a major step in cultural evolution. Language, especially written language, was sometimes thought to have supernatural status or powers -- hence the term "hieroglyphics", or "sacred carvings".

The science of linguistics describes the structure of language and the relationship between languages. There are estimated to be some 6,000 different languages, including sign languages, used today.

Music

Main article: music

Music is a natural intuitive phenomenon operating in the three worlds of time, pitch, and energy, and under the three distinct and interrelated organisation structures of rhythm, harmony, and melody.

Composing, improvising and performing music are all art forms. Listening to music is perhaps the most common form of entertainment, while learning and understanding it are popular disciplines. There are a wide variety of music genres and ethnic musics.

Government, politics and the state

Main articles: government, politics and state

A state is an organized political community occupying a definite territory, having an organized government, and possessing internal and external sovereignty. Recognition of the state's claim to independence by other states, enabling it to enter into international agreements, is often important to the establishment of its statehood. The "state" can also be defined in terms of domestic conditions, specifically, as conceptualized by Max Weber, "a state is a human community that (successfully) claims the monopoly of the legitimate use of physical force within a given territory." [8]

Government can be defined as the political means of creating and enforcing laws; typically via a bureaucratic hierarchy.

Politics is the process by which decisions are made within groups. Although the term is generally applied to behaviour within governments, politics is also observed in all human group interactions, including corporate, academic, and religious institutions. Many different political systems exist, as do many different ways of understanding them, and many definitions overlap. The most common form of government worldwide is a republic, however other examples include monarchy, social democracy, military dictatorship and theocracy.

All of these issues have a direct relationship with economics.

Trade and economics

Main articles: trade and economics

Trade is the voluntary exchange of goods, services, or both, and a form of economics. A mechanism that allows trade is called a market. The original form of trade was barter, the direct exchange of goods and services. Modern traders instead generally negotiate through a medium of exchange, such as money. As a result, buying can be separated from selling, or earning. The invention of money (and later credit, paper money and non-physical money) greatly simplified and promoted trade.

Trade exists for many reasons. Due to specialisation and division of labor, most people concentrate on a small aspect of manufacturing or service, trading their labour for products. Trade exists between regions because different regions have an absolute or comparative advantage in the production of some tradable commodity, or because different regions' size allows for the benefits of mass production. As such, trade between locations benefits both locations.

Economics is a social science that studies the production, distribution, trade and consumption of goods and services.

Economics, which focuses on measurable variables, is broadly divided into two main branches: microeconomics, which deals with individual agents, such as households and businesses, and macroeconomics, which considers the economy as a whole, in which case it considers aggregate supply and demand for money, capital and commodities. Aspects receiving particular attention in economics are resource allocation, production, distribution, trade, and competition. Economic logic is increasingly applied to any problem that involves choice under scarcity or determining economic value. Mainstream economics focuses on how prices reflect supply and demand, and uses equations to predict consequences of decisions.

War

Main article: War

War is a state of widespread conflict between states, organisations, or relatively large groups of people, which is characterised by the use of lethal violence between combatants or upon civilians.

A common perception of war is a series of military campaigns between at least two opposing sides involving a dispute over sovereignty, territory, resources, religion or other issues. A war said to liberate an occupied country is sometimes characterised as a " war of liberation", while a war between internal elements of a state is a civil war.

There have been a wide variety of rapidly advancing tactics throughout the history of war, ranging from conventional war to asymetric warfare to total war and unconventional warfare. Techniques have nearly always included hand to hand combat, the usage of ranged weapons, propaganda, Shock and Awe, and ethnic cleansing. Military intelligence has always played a key role in determining victory and defeat. In modern warfare, soldiers and armoured fighting vehicles are used to control the land, warships the seas, and air power the skies.

Througout history there has been a constant strugle between defense and offense, armour and the weapons designed to breach it. Modern examples include the bunker buster bomb, and the bunkers for which they are designed to destroy.

Many see war as destructive in nature, and a negative correlation has been shown between trade and war.

Artifacts, science, and technology

Main articles: Archaeology, Technology and Science

Human cultures are both characterized and differentiated by the objects that they make and use. Archaeology attempts to tell the story of past or lost cultures in part by close examination of the artifacts they produced. Early humans left stone tools, pottery and jewellery that are particular to various regions and times.

Improvements in technology are passed from one culture to another. For instance, the cultivation of crops arose in several different locations, but quickly spread to be an almost ubiquitous feature of human life. Similarly, advances in weapons, architecture and metallurgy are quickly disseminated.

Such techniques can be passed on by oral tradition. The development of writing, itself a type of artifact, made it possible to pass information from generation to generation and from region to region with greater accuracy.

Together, these developments made possible the commencement of civilisation and urbanisation, with their inherently complex social arrangements. Eventually this led to the institutionalisation of the development of new technology, and the associated understanding of the way the world functions. This science now forms a central part of human culture.

In recent times, physics and astrophysics have come to play a central role in shaping what is now known as physical cosmology, that is, the understanding of the universe through scientific observation and experiment. This discipline, which focuses on the universe as it exists on the largest scales and at the earliest times, begins by arguing for the big bang, a sort of cosmic explosion from which the universe itself is said to have erupted ~13.7 ± 0.2 billion (10⁹) years ago. After its violent beginnings and until its very end, scientists then propose that the entire history of the universe has been an orderly progression governed by physical laws.

Mind

Consciousness is a state of mind, said to possess qualities such as, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment.

The way in which the world is experienced is the subject of much debate and research in philosophy of mind, psychology, brain biology, neurology, and cognitive science.

Humans, often mentioned with other species, are variously said to possess consciousness, self-awareness, and a mind, the fruition of which are senses and perceptions. Each human has a subjective view of existence, the passage of time, and free will.

There are many debates about the extent to which the mind constructs or experiences the outer world, and regarding the definitions and validity of many of the terms used above.

Cognitive scientist Daniel Dennett, for example, argues that there is no such thing as a narrative centre called mind, but that instead there is simply a collection of sensory inputs and outputs: different kinds of software running in parallel (Dennett, 1991) .

Psychology and human ethology

Main articles: Psychology and Ethology

Psychology is an extremely broad field, encompassing many different approaches to the study of mental processes and behaviour.

Psychology does not necessarily refer to the brain or nervous system and can be framed purely in terms of phenomenological or information processing theories of the mind. Increasingly, though, an understanding of brain function is being included in psychological theory and practice, particularly in areas such as artificial intelligence, neuropsychology, and cognitive neuroscience.

The nature of thought is another core interest in psychology. Cognitive psychology studies cognition, the mental processes underlying behaviour. It uses information processing as a framework for understanding the mind. Perception, learning, problem solving, memory, attention, language and emotion are all well researched areas. Cognitive psychology is associated with a school of thought known as cognitivism, whose adherents argue for an information processing model of mental function, informed by positivism and experimental psychology. Techniques and models from cognitive psychology are widely applied and form the mainstay of psychological theories in many areas of both research and applied psychology.

Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development.

Social psychology intertwines sociology with psychology in their shared study of the nature and causes of human social behaviour, with an emphasis on how people think towards each other and how they relate to each other. Social Psychology aims to understand how we make sense of social situations.

The behaviour and mental processes of animals (human and non-human) can be described through animal cognition, ethology, and comparative psychology as well.

Human ecology is an academic discipline that investigates how humans and human societies interact with their environment, nature and the human social environment.

Philosophy

Main articles: Philosophy and Philosophy of mind

Philosophy is a discipline or field of study involving the investigation, analysis, and development of ideas at a general, abstract, or fundamental level. It is the discipline searching for a general understanding of values and reality by chiefly speculative rather than observational means comprising as its core logic, ontology or metaphysics, epistemology, and axiology which includes the branches of ethics and aesthetics. The term covers a very wide range of approaches, and is also used to refer to a worldview, to a perspective on an issue, or to the positions argued for by a particular philosopher or school of philosophy.

Metaphysics is a branch of philosophy concerned with the study of "first principles" and "being" ( ontology). Problems that were not originally considered metaphysical have been added to metaphysics. Other problems that were considered metaphysical problems for centuries are now typically relegated to their own separate subheadings in philosophy, such as philosophy of religion, philosophy of mind, philosophy of perception, philosophy of language, and philosophy of science. In rare cases subjects of metaphysical research have been found to be entirely physical and natural.

The mind is the term most commonly used to describe the higher functions of the human brain, particularly those of which humans are subjectively conscious, such as personality, thought, reason, memory, intelligence and emotion. Other species of animals share some of these mental capacities, and it is also used in relation to supernatural beings, as in the expression "the mind of God." The term is used here only in relation to humans.

There are many Philosophies of mind, the most common relating to the nature of being, and ones way of being, or purpose.

Adi Shankara in the East proposed Advaita Vedanta, a popular argument for monism (the metaphysical view that all is of one essential essence, substance or energy).

Another type of monism is physicalism or materialism, which holds that only the physical is real, and that the mental can be reduced to the physical. Idealism and phenomenalism, on the contrary, assert the existence of the mind and deny, or at the least deny the importance of, an external reality that exists independently of the mind.

René Descartes proposed that both mind and matter exist, and that the one cannot be reduced to the other. This represents the philosophy of mind form of dualism. Dvaita is the Hindu philosophy that incorporates a form of dualism that distinguishes God from souls.

Johannes Jacobus Poortman proposed a Pluralist classification of a number of different mystical and metaphysical views. Vishishtadvaita is the Hindu philosophy incorporating pluralism.

Plato, Aristotle, Socrates, Hume, Kant, Locke, Spinoza, Nietzsche and Wittgenstein are also philosophers of note in the history of human thought.

Many religions and spiritual traditions hold that humans have both a body and a soul, usually proposing that the soul can in some way survive the death of the body. Although the soul sometimes is equated with the mind, this is not always the case.

As a finer distinction between religion and philosophy, esoteric cosmology is distinguished from religion in its more sophisticated construction and reliance on intellectual understanding rather than faith, and from philosophy in its emphasis on techniques of psycho-spiritual transformation.

In between the doctrines of religion and science, stands the philosophical perspective of metaphysical cosmology. This ancient field of study seeks to draw logical conclusions about the nature of the universe, humanity, god and/or their connections based on the extension of some set of presumed facts borrowed from religion and/or observation.

What might be called the core metaphysical problems would be the ones which have always been considered metaphysical. What most of such problems have in common is that they are the problems of ontology, the science of being or existence as well as the basic categories thereof—trying to find out what entities and what types of entities exist. Ontology has strong implications for the conceptions of reality.

Motivation

Motivation is the driving force of desire behind all actions of any organism.

Motivation is based on emotion, specifically, on the search for satisfaction (positive emotional experiences), and the avoidance of conflict; positive and negative are defined by the individual brain state, not by social norms: a person may be driven to self-injury or violence because their brain is conditioned to create a positive response to these actions. Motivation is important because it is involved in the performance of all learned responses.

Within psychology, conflict avoidance and the libido are seen to be primary motivators. Within economics motivation is often seen to be based on Financial incentives, Moral incentives, or Coercive incentives. Religions generally posit Godly or demonic influences.

For many love is the central motivation in life. The classical Greeks had four words for love:

• Eros : Romantic love
• Philia : Friendship, Love (but especially platonic love).
• Agape : Divine, unconditioned love. Many religious persons will refer to the love that they feel towards, or receive from God as divine love or Agape.
• Storge : Natural familial affection.

Happiness or being happy is a condition which humans can have. The definition of happiness is one of the greatest philosophical topics, at least since the time of Socrates, and is especially central to Ethics, being the starting point of Aristotle's ethical works. Some people might define it as the best condition which a human can have - a condition of mental and physical health. Others may define it as freedom from want and distress; consciousness of the good order of things; assurance of one's place in the universe or society, inner peace, and so forth. Aristotle conceived of Eudaimonia, a society governed by pursuit of happiness.

The happy life is thought to be one of excellence; now an excellent life requires exertion and does not consist of amusement. If Eudaimonia, or happiness, is an activity in accordance with excellence, it's reasonable that it should be in accordance with the highest excellence, and will be that of the best thing in us."

Aristotle, " Nicomachean Ethics"

Self-reflection and humanism

Thales of Miletus, when asked what was difficult, answered in a well-known apophthegm: "To Know Thyself" γνῶθι σεαυτόν (also attributed to Socrates, and inscribed on the Temple of Apollo at Delphi).

Humans often consider themselves to be the dominant species on Earth, and the most advanced in intelligence and ability to manage their environment. This belief is especially strong in modern Western culture. Alongside such claims of dominance we often find radical pessimism because of the frailty and brevity of human life. In the Hebrew Bible, for example, dominion of man is promised in Genesis 1:28, but the author of Ecclesiastes bewails the vanity of all human effort.

The Ancient Greek philosopher Protagoras made the famous claim that "Man is the measure of all things; of what is, that it is; of what is not, that it is not." Aristotle describes man as the "communal animal" (ζῷον πολιτικόν), i.e. emphasising society-building as a central trait of human nature, and "animal with sapience" (ζῷον λόγον ἔχων, animal rationale), a term that also inspired the species' taxonomy, Homo sapiens. This philosophy is today called " Humanism".

Humanism as a philosophy defines a socio-political doctrine the bounds of which are not constrained by those of locally developed cultures, but which seeks to include all of humanity and all issues common to human beings. Because spiritual beliefs of a community often manifests as religious doctrine, the history of which is as factious as it is unitive, secular humanism grew as an answer to the need for a common philosophy that transcended the cultural boundaries of local moral codes and religions. Many humanists are religious, however, and see humanism as simply a mature expression of a common truth present in most religions. Humanists affirm the possibility of an objective truth and accept that human perception of that truth is imperfect. The most basic tenets of humanism are that humans matter and can solve human problems, and that science, freedom of speech, rational thought, democracy, and freedom in the arts are worthy pursuits or goals for all peoples. Modern humanism depends on reason and logic and rejects the supernatural.

From a scientific viewpoint, H. sapiens certainly is among the most generalised species on Earth, and few single species occupy as many diverse environments as humans. Various attempts have been made to identify a single behavioural characteristic that distinguishes humans from all other animals, e.g. the ability to make and use tools, the ability to alter the environment, language use, and the development of complex social structures. Some anthropologists think that these readily observable characteristics (tool-making and language) are based on less easily observable mental processes that might be unique among humans: the ability to think symbolically, in the abstract or logically. Others, that human capacity for symbolic thought is a development from the capacity to manipulate tools or the development of speech. It is difficult however to arrive at a set of attributes that includes all humans, and humans only. The wish to find unique human characteristics could be more a matter of anthropocentrism than of zoology in the end.

Spirit

Humans apply different approaches in an attempt to answer fundamental questions about topics such as the nature of the universe ( cosmology), its creation ( cosmogony) and destruction ( eschatology), and our place in it — who we are, why we are here, what happens after life, and more. Broadly speaking, these questions can be addressed and beliefs formed from a number of approaches and perspectives, such as religion, science, philosophy (particularly ontology within metaphysics), esotericism, and mysticism. However, these approaches are not mutually exclusive. For example, an expert scientist can be highly religious, have a philosophy of life, and follow any number of esoteric or mystical practices.

Four major approaches to forming beliefs about the nature of the universe include religious cosmology, scientific or physical cosmology, metaphysical cosmology and esoteric cosmology.

The earliest form of cosmology appears in the origin beliefs of many religions as they seek to explain the existence and nature of the world. In many cases, views about the creation ( cosmogony) and destruction ( eschatology) of the universe play a central role in shaping a framework of religious cosmology for understanding a person's role in the universe and its relationship to one or more divine beings.

Religion—sometimes used interchangeably with “ faith” or “ belief system”—is commonly defined as belief concerning the supernatural, sacred, or divine, and the moral codes, practices, values, institutions and rituals associated with such belief. In the course of its development, it has taken on many forms that vary by culture and individual perspective.

There are a number of perspectives regarding the fundamental nature and substance of humans. These are by no means mutually exclusive, and this list is by no means exhaustive.

• Materialism holds that humans are physical beings without any supernatural or spiritual component. Materialism holds to naturalism and rejects supernaturalism.
• Monotheism believes that a single deity, who is either the only one in existence, or who incorporates or excels all lesser deities, created humanity. Humans are thus bound by filial and moral duty, and cared for by paternal providence. In all the Abrahamic religions (Judaism, Christianity, and Islam), humans are lord or steward over the earth and all its other creatures. The Bible and Koran hold that humankind was created as a spiritually and physically perfect entity, but through the sins of self-idolatry and disobedience lost its perfection.
• Pantheism holds that human beings, as part of the world, are a part of God, who is identified with the world (and vice versa). ( Panentheism is similar, but holds that the world is God, but that God is more than the world.) Monism, animism, Vedic religion, and other forms of Eastern philosophy have related beliefs.
• Monism is the metaphysical view that all things are of one essential essence, substance or energy. Monistic theism, a variant of both monism and Monotheism, views God as both immanent and transcendent. Both are dominant themes in Hinduism and Surat Shabd Yoga, that hold humans are special in that they can conceptualise God and strive to achieve him, but their soul is akin to a divine spark just as an animal's is.

• Taoism may be rendered as religion, morality, duty, knowledge, rationality, ultimate truth, path, or taste. Its semantics vary widely depending on the context. Tao is generally translated into English as "The Way".
• In polytheistic religions, a whole pantheon of gods holds sway. Polytheistic deites often have individual interests or portfolios, and are arranged in a hierarchy of their own— for example, Zeus is the Greek god of thunder as well as king of the gods. Humans are mainly characterised by their inferiority to the gods, sometimes reflected in a hierarchical society ruled by dynasties that claim divine descent.
• Animism is the belief that objects and ideas including other animal species, tools, and natural phenomena have or are expressions of living spirits. Rituals in animistic cultures are often performed by shamans or priests, who are usually seen as possessing spiritual powers greater than or external to the normal human experience.
• Esotericism refers to “hidden” knowledge available only to the advanced, privileged, or initiated, as opposed to exoteric knowledge, which is public. It is used especially for spiritual practices.
• Mysticism (meaning "that which is concealed") is the pursuit of achieving communion with, or conscious awareness of, ultimate reality, the divine, spiritual truth, or God through direct, personal experience (intuition or insight); the belief in the existence of realities beyond perceptual or intellectual apprehension that are central to being and directly accessible through personal experience; or the belief that such experience is an important source of knowledge.