Utilization of food by the body
They desire to understand the world, including both past, present, and future, and even study other animals and themselves. Retrieved 11 May A complete protein includes all of the essential amino acids. The way glucose molecules link together makes them digestible starch or non-digestible fiber. All naturally fiber-rich foods are also rich in carbohydrates.
These can impose particular costs such as more or less expensive heating or clothing requirements. Conventions and customs determine the commodity requirements of expected standards of behaviour and consumption, so that relative income poverty in a rich community may translate into absolute poverty in the space of capability. The diagnosis of capability failures, or significant interpersonal variations in capability, directs attention to the relevant causal pathways responsible.
For example, the physically handicapped often have more expensive requirements to achieve the same capabilities, such as mobility, while at the same time they also have greater difficulty earning income in the first place.
The concept of a capability has a global-local character in that its definition abstracts from particular circumstances, but its realization depends on specific local requirements. This makes the Capability Approach applicable across political, economic, and cultural borders.
For example, Sen points out that being relatively income poor in a wealthy society can entail absolute poverty in some important capabilities, because they may require more resources to achieve. For example, the capability for employment may require more years of education in a richer society. Many capabilities will have underlying requirements that vary strongly with social circumstances although others, such as adequate nourishment, may vary less.
Presently in Saudi Arabia, for example, women must have the company of a close male relative to appear in public, and require a chauffeur and private car to move between private spaces since they are not permitted to use public transport or drive a car themselves. The Capability Approach only identifies such capability failures and diagnoses their causes. However, if there is general agreement in the first place that such capabilities should be equally guaranteed for all, there is a clear basis for criticizing clearly unjust social norms as the source of relative deprivation and thus as inconsistent with the spirit of such a guarantee.
The capability approach takes a multi-dimensional approach to evaluation. Capability analysis rejects the presumption that unusual achievement in some dimensions compensates for shortfalls in others.
Capability evaluation is informationally demanding and its precision is limited by the level of agreement about which functionings are valuable.
However, Sen has shown that even where only elementary evaluation of quite basic capabilities is possible for example, life-expectancy or literacy outcomes , this can still provide much more, and more relevant, action-guiding information than the standard alternatives.
In particular, by making perspicuous contrasts between successes and failures the capability approach can direct political and public attention to neglected dimensions of human well-being. For example, countries with similar levels of wealth can have dramatically different levels of aggregate achievement - and inequality - on such non-controversially important dimensions as longevity and literacy.
And, vice versa , countries with very small economies can sometimes score as highly on these dimensions as the richest. This demonstrates both the limitations of relying exclusively on economic metrics for evaluating development, and the fact that national wealth does not pose a rigid constraint on such achievements that GNP is not destiny.
The Philippines does more with less. Rawls suggests that this constitutes the privileging of a particular non-political comprehensive conception of rational advantage or the good. Theories of justice that focus on the distribution of means implicitly assume that they will provide the same effective freedom to live the life one has reason to value to all, but this excludes relevant information about the relationship between particular people and resources.
That means that even if it happened that everyone had the same conception of the good, and the same bundle of resources, the fact of heterogeneity would mean that people would have differential real capability to pursue the life they had reason to value. Therefore, Sen argues, a theory of justice based on fairness should be directly and deeply concerned with the effective freedom — capability — of actual people to achieve the lives they have reason to value.
Sen does not say which capabilities are important or how they are to be distributed: Different capability theorists have taken different approaches to the valuation of capabilities, from procedural accounts to ones based on substantive understandings of human nature. There are related concerns about the institutional structure of the Capability Approach, for example, brought by the Rawlsian social justice theorist, Thomas Pogge Pogge How should capabilities be weighted against each other and non-capability concerns?
For example, should some basic capabilities be prioritized as more urgent? What does the Capability Approach imply for interpersonal equality? How should capability enhancement be paid for? How much responsibility should individuals take for the results of their own choices? What should be done about non-remediable deprivations, such as blindness?
There are several components to this family of criticisms. Martha Nussbaum, for example, points out that a just society requires balancing and even limiting certain freedoms, such as regarding the expression of racist views, and in order to do so must make commitments about which freedoms are good or bad, important or trivial Nussbaum Nevertheless Sen is clear in his view that the value of social goods is only derivative upon the reflective choices of those concerned see, for example, Sen a.
With regard to freedom, Sen distinguishes the ability to choose between different options from the value of those options. These two together make up effective freedom or capability. This relates to its concern with tracing the causal pathways of specific deprivations, with how exactly different people are able or unable to convert resources into valuable functionings. However it has been criticized for its crudeness.
It contains only three dimensions — longevity, literacy mean years of schooling , and Gross National Income per capita — which are weighted equally. It also requires detailed information on the real inter-personal variations in translating commodities into functionings. It is not clear however that such informational ambitions could ever be realized.
Nevertheless it has succeeded in demonstrating that capability related information can be used systematically as a credible supplement to economic metrics. Sen accepts that some information about capabilities is easier to obtain than others. Firstly, he argues that we already have quite extensive information about some basic capabilities even for many quite poor countries, such as about health, that can and should be systematically assessed.
There is therefore no need to limit our assessment to economic metrics which firstly count the wrong things means and secondly also come with significant measurement error despite their apparent numerical precision. Secondly, he argues that if researchers accept the capability space as the new priority for evaluation that will motivate the development of new data collection priorities and methods.
Nevertheless, the Capability Approach is not concerned with information collection for its own sake, but rather with the appropriate use of information for assessment. It is therefore not committed to, nor does its effective use require, building a perfect information collection and assessment bureaucracy.
Some theoretical accounts are primarily concerned with operationalising the evaluative dimension of the Capability Approach: This section provides a brief outline of some of these.
Instead she proposes a procedural approach to the selection of capabilities for particular purposes, such as the evaluation of gender inequality in terms of capabilities Robeyns She claims that valuational procedures that meet her criteria provide epistemic, academic, and political legitimacy for empirically evaluating capability. Her five criteria are:. All proposed list elements should be explicit, so they can be discussed and debated.
The method of generating the list should be made explicit so it can be scrutinized. The level of abstraction of the list should be appropriate to its purposes, whether for philosophical, legal, political, or social discussion.
If the list is intended for empirical application or public policy then it should be drawn up in two distinct stages, first an ideal stage and then a pragmatic one that reflects perhaps temporary feasibility constraints on information and resources. The list should include all important elements and those elements should not be reducible to others though they may overlap.
Sabina Alkire has developed a philosophically grounded framework for the participatory valuation and evaluation of development projects in terms of capability enhancement Alkire This allows her to go beyond standard cost-benefit analyses of development projects in financial terms to investigate which capabilities that the people concerned have reason to value are enhanced and by how much.
The intrinsically important dimensions identified by this method are: One of the advantages Alkire claims for her approach is its ability to elicit what the people whose lives are the subject of development projects really consider valuable, which may sometimes surprise external planners and observers.
Her use of the participatory approach for assessing NGO fieldwork in Pakistan showed, for example, that even the very poor can and do reasonably value other things than material well-being, such as religion and social participation.
Elizabeth Anderson has proposed a partial theory of justice based on equal capability of democratic citizenship Anderson Anderson takes equality in social relationships as the focus for her egalitarian theory of justice and argues that one should analyze the requirements of such equality in terms of the social conditions supporting it as a capability.
Positively, they are entitled to whatever capabilities are necessary for functioning as an equal citizen in a democratic state Anderson , John Alexander has proposed a capability theory based on a Republican understanding of the importance of freedom as non-domination Alexander But he argues that the Capability Approach should go further to elaborate this commitment to real freedom in Republican terms.
For example, the ability of a physically disabled but socially well-connected person to travel outside whenever she wants by arranging the help of friends, family and voluntary organizations. In addition the Republican perspective requires that her capability for mobility should be independent of context. For example, in the form of a guaranteed legal right to government assistance on demand, or by the provision of her own specially adapted self-drive vehicle.
Otherwise she may be said to be still deprived since her capability is not completely free. Domination should also be integrated into capability evaluation because it will often be a cause of capability deprivation. It is no coincidence that the people who are most capability deprived are often the poorest and weakest in society, and as a result also vulnerable to yet further exploitation.
Martha Nussbaum has developed the most systematic, extensive, and influential capability theory of justice to date. Being able to have good health, including reproductive health; to be adequately nourished; to have adequate shelter. Being able to move freely from place to place; to be secure against violent assault, including sexual assault and domestic violence; having opportunities for sexual satisfaction and for choice in matters of reproduction.
Senses, Imagination, and Thought. Being able to have pleasurable experiences and to avoid non-beneficial pain. Being able to have attachments to things and people outside ourselves; to love those who love and care for us, to grieve at their absence; in general, to love, to grieve, to experience longing, gratitude, and justified anger.
Supporting this capability means supporting forms of human association that can be shown to be crucial in their development. This entails protection for the liberty of conscience and religious observance. Being able to live with and toward others, to recognize and show concern for other human beings, to engage in various forms of social interaction; to be able to imagine the situation of another.
Protecting this capability means protecting institutions that constitute and nourish such forms of affiliation, and also protecting the freedom of assembly and political speech. Having the social bases of self-respect and nonhumiliation; being able to be treated as a dignified being whose worth is equal to that of others. This entails provisions of nondiscrimination on the basis of race, sex, sexual orientation, ethnicity, caste, religion, national origin.
Being able to live with concern for and in relation to animals, plants, and the world of nature. Being able to laugh, to play, to enjoy recreational activities.
Being able to hold property both land and movable goods , and having property rights on an equal basis with others; having the right to seek employment on an equal basis with others; having the freedom from unwarranted search and seizure. In work, being able to work as a human being, exercising practical reason, and entering into meaningful relationships of mutual recognition with other workers. In her early contributions to the capability approach, Nussbaum justified the composition of her list by explicitly Aristotelian argument about the perfectionist requirements of the truly human life Nussbaum This means that she now presents her list as a proposal that is neutral with respect to particular conceptions of the good, but can be endorsed by many different groups in a society through an overlapping consensus.
However the list components themselves remain almost identical and retain a distinctively Aristotelian cast. She argues that her list of 10 fundamental capabilities follow from the requirements of dignity and have been tested and adapted over the course of an extensive cross-cultural dialogue she has carried out, particularly in India as related in her book, Women and Human Development , The threshold is a 'sufficientarian' principle that specifies the minimum requirements of justice: Access to these capabilities is required by human dignity, Nussbaum argues, but this does not mean that a life lacking in any of these, whether from external deprivation or individual choice, is a less than human life.
Choice and deprivation are different however. If someone lacks access to these capabilities, for example, to be well-nourished bodily health , that reflects a failure by society to respect her human dignity.
If someone chooses not to take up her opportunities to certain capabilities, for example, to adopt an ascetic life-style and fast for religious reasons at the expense of her bodily health, respecting that choice is also an aspect of respecting her dignity. Nussbaum suggests that her list, together with the precise location of the threshold, should be democratically debated and incorporated into national constitutional guarantees, international human rights legislation and international development policy.
For example, freedom of speech may be defined differently in law in the USA and Germany, because of their different histories, without endangering the fundamental capability. Nevertheless, because each capability is equally centrally important and a shortfall in any area is significant in itself, the scope for governments to make trade-offs between them, for example, on the basis of quantitative cost-benefit analysis, is limited.
Others have argued that her legal-moral-philosophical orientation is elitist and over-optimistic about what constitutions and governments are like and are capable of Menon ; is over-specified and paternalistic yet still misses out important capabilities and is inappropriate for many uses, such as quality of life measurement or development fieldwork Alkire , In response to such criticisms, Nussbaum has defended the contents of her list as having cross-cultural credibility, but also emphasised that she is not trying to impose a definitive capability theory on everyone.
She makes a clear and explicit distinction between the dimensions of justification why her theory is best and implementation its more humble meta-status as an object for democratic deliberation and decision by those concerned Nussbaum Nussbaum and Sen collaborated in the late s and early s and since they are the most high-profile writers in the Capability Approach their accounts are often elided, despite significant differences.
The accounts of Sen and Nussbaum differ significantly in ways that relate to their different concerns and backgrounds. Which Functionings Matter for the Good Life? This is in contrast with the oceans that may be inside larger icy satellites like Ganymede, Callisto, or Titan, where layers of high-pressure phases of ice are thought to underlie the liquid water layer.
Hydrogen sulfide has been proposed as a hypothetical solvent for life and is quite plentiful on Jupiter's moon Io , and may be in liquid form a short distance below the surface. The scientific search for extraterrestrial life is being carried out both directly and indirectly.
Scientists search for biosignatures within the Solar System by studying planetary surfaces and examining meteorites. It is designed to assess the past and present habitability on Mars using a variety of scientific instruments.
The rover landed on Mars at Gale Crater in August The Gaia hypothesis stipulates that any planet with a robust population of life will have an atmosphere in chemical disequilibrium, which is relatively easy to determine from a distance by spectroscopy.
However, significant advances in the ability to find and resolve light from smaller rocky worlds near their star are necessary before such spectroscopic methods can be used to analyze extrasolar planets.
To that effect, the Carl Sagan Institute was founded in and is dedicated to the atmospheric characterization of exoplanets in circumstellar habitable zones. In August , findings by NASA, based on studies of meteorites found on Earth, suggest DNA and RNA components adenine , guanine and related organic molecules , building blocks for life as we know it, may be formed extraterrestrially in outer space. In August , and in a world first, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde , in a distant star system.
The molecule was found around the protostellar binary IRAS , which is located light years from Earth. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation.
Projects such as SETI are monitoring the galaxy for electromagnetic interstellar communications from civilizations on other worlds. The length of time required for a signal to travel across the vastness of space means that any signal detected would come from the distant past. Some astronomers search for extrasolar planets that may be conducive to life, narrowing the search to terrestrial planets within the habitable zone of their star.
There is at least one planet on average per star. The nearest known exoplanet is Proxima Centauri b , located 4. Almost all of the planets detected so far are within the Milky Way, but there have also been a few possible detections of extragalactic planets. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life.
One sign that a planet probably already contains life is the presence of an atmosphere with significant amounts of oxygen , since that gas is highly reactive and generally would not last long without constant replenishment. This replenishment occurs on Earth through photosynthetic organisms. One way to analyze the atmosphere of an exoplanet is through spectrography when it transits its star, though this might only be feasible with dim stars like white dwarfs.
The science of astrobiology considers life on Earth as well, and in the broader astronomical context. In , "remains of biotic life " were found in 4.
In , University of California, Santa Cruz , astronomer and astrophysicist Frank Drake devised the Drake equation as a way to stimulate scientific dialogue at a meeting on the search for extraterrestrial intelligence SETI. The equation is best understood not as an equation in the strictly mathematical sense, but to summarize all the various concepts which scientists must contemplate when considering the question of life elsewhere.
Drake's proposed estimates are as follows, but numbers on the right side of the equation are agreed as speculative and open to substitution:. The Drake equation has proved controversial since several of its factors are uncertain and based on conjecture, not allowing conclusions to be made. Based on observations from the Hubble Space Telescope , there are between and billion galaxies in the observable universe. Even if it is assumed that only one out of a billion of these stars has planets supporting life, there would be some 6.
A study based on results from the Kepler spacecraft estimated that the Milky Way contains at least as many planets as it does stars, resulting in — billion exoplanets. The apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for such civilizations is known as the Fermi paradox. Cosmic pluralism, the plurality of worlds, or simply pluralism, describes the philosophical belief in numerous "worlds" in addition to Earth, which might harbor extraterrestrial life.
Before the development of the heliocentric theory and a recognition that the Sun is just one of many stars,  the notion of pluralism was largely mythological and philosophical. With the scientific and Copernican revolutions , and later, during the Enlightenment , cosmic pluralism became a mainstream notion, supported by the likes of Bernard le Bovier de Fontenelle in his work Entretiens sur la pluralité des mondes. The astronomer Camille Flammarion promoted the notion of cosmic pluralism in his book La pluralité des mondes habités.
There was a dramatic shift in thinking initiated by the invention of the telescope and the Copernican assault on geocentric cosmology. Once it became clear that Earth was merely one planet amongst countless bodies in the universe, the theory of extraterrestrial life started to become a topic in the scientific community.
The best known early-modern proponent of such ideas was the Italian philosopher Giordano Bruno , who argued in the 16th century for an infinite universe in which every star is surrounded by its own planetary system. Bruno wrote that other worlds "have no less virtue nor a nature different to that of our earth" and, like Earth, "contain animals and inhabitants".
In Baroque literature such as The Other World: The Societies and Governments of the Moon by Cyrano de Bergerac , extraterrestrial societies are presented as humoristic or ironic parodies of earthly society.
Fontanelle 's "Conversations on the Plurality of Worlds" translated into English in offered similar excursions on the possibility of extraterrestrial life, expanding, rather than denying, the creative sphere of a Maker. The possibility of extraterrestrials remained a widespread speculation as scientific discovery accelerated. William Herschel , the discoverer of Uranus , was one of many 18th—19th-century astronomers who believed that the Solar System is populated by alien life.
Other luminaries of the period who championed "cosmic pluralism" included Immanuel Kant and Benjamin Franklin. At the height of the Enlightenment , even the Sun and Moon were considered candidates for extraterrestrial inhabitants.
Speculation about life on Mars increased in the late 19th century, following telescopic observation of apparent Martian canals —which soon, however, turned out to be optical illusions. Wells to write the novel The War of the Worlds in , telling of an invasion by aliens from Mars who were fleeing the planet's desiccation.
Spectroscopic analysis of Mars's atmosphere began in earnest in , when U. The science fiction genre, although not so named during the time, developed during the late 19th century.
Jules Verne 's Around the Moon features a discussion of the possibility of life on the Moon, but with the conclusion that it is barren. Stories involving extraterrestrials are found in e. Wells was published in which stands at the beginning of the popular idea of the "Martian invasion" of Earth prominent in 20th-century pop culture.
Most unidentified flying objects or UFO sightings  can be readily explained as sightings of Earth-based aircraft, known astronomical objects , or as hoaxes. The possibility of extraterrestrial life on the Moon was ruled out in the s, and during the s it became clear that most of the other bodies of the Solar System do not harbor highly developed life, although the question of primitive life on bodies in the Solar System remains open.
The failure so far of the SETI program to detect an intelligent radio signal after decades of effort has at least partially dimmed the prevailing optimism of the beginning of the space age. Notwithstanding, belief in extraterrestrial beings continues to be voiced in pseudoscience , conspiracy theories, and in popular folklore , notably " Area 51 " and legends. It has become a pop culture trope given less-than-serious treatment in popular entertainment.
At the same time, the data returned by space probes, and giant strides in detection methods, have allowed science to begin delineating habitability criteria on other worlds, and to confirm that at least other planets are plentiful, though aliens remain a question mark. In , geologist and paleontologist Peter Ward and astrobiologist Donald Brownlee published a book entitled Rare Earth: Why Complex Life is Uncommon in the Universe.
Ward and Brownlee are open to the idea of evolution on other planets that is not based on essential Earth-like characteristics such as DNA and carbon. Theoretical physicist Stephen Hawking in warned that humans should not try to contact alien life forms. He warned that aliens might pillage Earth for resources.
In November , the White House released an official response to two petitions asking the U. According to the response, "The U. In , the exoplanet Keplerf was discovered, along with Keplere and Keplerc. A related special issue of the journal Science , published earlier, described the discovery of the exoplanets. On 17 April , the discovery of the Earth-size exoplanet Keplerf , light-years from Earth , was publicly announced;  it is the first Earth-size planet to be discovered in the habitable zone and it has been hypothesized that there may be liquid water on its surface.
On 13 February , scientists including Geoffrey Marcy , Seth Shostak , Frank Drake and David Brin at a convention of the American Association for the Advancement of Science , discussed Active SETI and whether transmitting a message to possible intelligent extraterrestrials in the Cosmos was a good idea;   one result was a statement, signed by many, that a "worldwide scientific, political and humanitarian discussion must occur before any message is sent".
The group contracted the services of the meter Robert C. From Wikipedia, the free encyclopedia. For other uses, see Astrobiology. Some major international efforts to search for extraterrestrial life. Clockwise from top left: The search for extrasolar planets image: Kepler telescope Listening for extraterrestrial signals indicating intelligence image: Allen array Robotic exploration of the Solar System image: Curiosity rover on Mars.
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