Theory of categories

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https://en.wikipedia.org/wiki/Theory_of_categories

In ontology, the theory of categories concerns itself with the categories of being: the highest genera or kinds of entities according to Amie Thomasson. To investigate the categories of being, or simply categories, is to determine the most fundamental and the broadest classes of entities. A distinction between such categories, in making the categories or applying them, is called an ontological distinction. Various systems of categories have been proposed, they often include categories for substances, properties, relations, states of affairs or events. A representative question within the theory of categories might articulate itself, for example, in a query like, "Are universals prior to particulars?"

Early development

The process of abstraction required to discover the number and names of the categories of being has been undertaken by many philosophers since Aristotle and involves the careful inspection of each concept to ensure that there is no higher category or categories under which that concept could be subsumed. The scholars of the twelfth and thirteenth centuries developed Aristotle's ideas. For example, Gilbert of Poitiers divides Aristotle's ten categories into two sets, primary and secondary, according to whether they inhere in the subject or not:

• Primary categories: Substance, Relation, Quantity and Quality
• Secondary categories: Place, Time, Situation, Condition, Action, Passion

Furthermore, following Porphyry’s likening of the classificatory hierarchy to a tree, they concluded that the major classes could be subdivided to form subclasses, for example, Substance could be divided into Genus and Species, and Quality could be subdivided into Property and Accident, depending on whether the property was necessary or contingent. An alternative line of development was taken by Plotinus in the second century who by a process of abstraction reduced Aristotle's list of ten categories to five: Substance, Relation, Quantity, Motion and Quality. Plotinus further suggested that the latter three categories of his list, namely Quantity, Motion and Quality correspond to three different kinds of relation and that these three categories could therefore be subsumed under the category of Relation. This was to lead to the supposition that there were only two categories at the top of the hierarchical tree, namely Substance and Relation. Many supposed that relations only exist in the mind. Substance and Relation, then, are closely commutative with Mind and Matter--this is expressed most clearly in the dualism of René Descartes.

Vaisheshika

Padārtha is a Sanskrit word for "categories" in Vaisheshika and Nyaya schools of Indian philosophy.

Stoic

The Stoics held that all beings (ὄντα)—though not all things (τινά)—are material. Besides the existing beings they admitted four incorporeals (asomata): time, place, void, and sayable. They were held to be just 'subsisting' while such a status was denied to universals. Thus, they accepted Anaxagoras's idea (as did Aristotle) that if an object is hot, it is because some part of a universal heat body had entered the object. But, unlike Aristotle, they extended the idea to cover all accidents. Thus, if an object is red, it would be because some part of a universal red body had entered the object.

They held that there were four categories.

1. Substance (ὑποκείμενον): The primary matter, formless substance, (ousia) that things are made of
2. Quality (ποιόν): The way matter is organized to form an individual object; in Stoic physics, a physical ingredient (pneuma: air or breath), which informs the matter
3. Somehow disposed (πως ἔχον): Particular characteristics, not present within the object, such as size, shape, action, and posture
4. Somehow disposed in relation to something (πρός τί πως ἔχον): Characteristics related to other phenomena, such as the position of an object within time and space relative to other objects

The Stoics outlined that our own actions, thoughts, and reactions are within our control. The opening paragraph of the Enchiridion states the categories as: "Some things in the world are up to us, while others are not. Up to us are our faculties of judgment, motivation, desire, and aversion. In short, whatever is our own doing." These suggest a space that is up to us or within our power. A simple example of the Stoic categories in use is provided by Jacques Brunschwig:

I am a certain lump of matter, and thereby a substance, an existent something (and thus far that is all); I am a man, and this individual man that I am, and thereby qualified by a common quality and a peculiar one; I am sitting or standing, disposed in a certain way; I am the father of my children, the fellow citizen of my fellow citizens, disposed in a certain way in relation to something else.

Aristotle

Main article: Categories (Aristotle)

One of Aristotle’s early interests lay in the classification of the natural world, how for example the genus "animal" could be first divided into "two-footed animal" and then into "wingless, two-footed animal". He realised that the distinctions were being made according to the qualities the animal possesses, the quantity of its parts and the kind of motion that it exhibits. To fully complete the proposition "this animal is ..." Aristotle stated in his work on the Categories that there were ten kinds of predicate where ...

"... each signifies either substance or quantity or quality or relation or where or when or being-in-a-position or having or acting or being acted upon".

He realised that predicates could be simple or complex. The simple kinds consist of a subject and a predicate linked together by the "categorical" or inherent type of relation. For Aristotle the more complex kinds were limited to propositions where the predicate is compounded of two of the above categories for example "this is a horse running". More complex kinds of proposition were only discovered after Aristotle by the Stoic, Chrysippus, who developed the "hypothetical" and "disjunctive" types of syllogism and these were terms which were to be developed through the Middle Ages and were to reappear in Kant's system of categories.

Category came into use with Aristotle's essay Categories, in which he discussed univocal and equivocal terms, predication, and ten categories:

• Substance, essence (ousia) – examples of primary substance: this man, this horse; secondary substance (species, genera): man, horse
• Quantity (poson, how much), discrete or continuous – examples: two cubits long, number, space, (length of) time.
• Quality (poion, of what kind or description) – examples: white, black, grammatical, hot, sweet, curved, straight.
• Relation (pros ti, toward something) – examples: double, half, large, master, knowledge.
• Place (pou, where) – examples: in a marketplace, in the Lyceum
• Time (pote, when) – examples: yesterday, last year
• Position, posture, attitude (keisthai, to lie) – examples: sitting, lying, standing
• State, condition (echein, to have or be) – examples: shod, armed
• Action (poiein, to make or do) – examples: to lance, to heat, to cool (something)
• Affection, passion (paschein, to suffer or undergo) – examples: to be lanced, to be heated, to be cooled

Plotinus

Plotinus in writing his Enneads around AD 250 recorded that "philosophy at a very early age investigated the number and character of the existents ... some found ten, others less .... to some the genera were the first principles, to others only a generic classification of existents". He realised that some categories were reducible to others saying "why are not Beauty, Goodness and the virtues, Knowledge and Intelligence included among the primary genera?" He concluded that such transcendental categories and even the categories of Aristotle were in some way posterior to the three Eleatic categories first recorded in Plato's dialogue Parmenides and which comprised the following three coupled terms:

• Unity/Plurality
• Motion/Stability
• Identity/Difference

Plotinus called these "the hearth of reality" deriving from them not only the three categories of Quantity, Motion and Quality but also what came to be known as "the three moments of the Neoplatonic world process":

• First, there existed the "One", and his view that "the origin of things is a contemplation"
• The Second "is certainly an activity ... a secondary phase ... life streaming from life ... energy running through the universe"
• The Third is some kind of Intelligence concerning which he wrote "Activity is prior to Intellection ... and self knowledge"

Plotinus likened the three to the centre, the radii and the circumference of a circle, and clearly thought that the principles underlying the categories were the first principles of creation. "From a single root all being multiplies". Similar ideas were to be introduced into Early Christian thought by, for example, Gregory of Nazianzus who summed it up saying "Therefore, Unity, having from all eternity arrived by motion at duality, came to rest in trinity".

Modern development

Kant and Hegel accused the Aristotelian table of categories of being 'rhapsodic', derived arbitrarily and in bulk from experience, without any systematic necessity.

The early modern dualism, which has been described above, of Mind and Matter or Subject and Relation, as reflected in the writings of Descartes underwent a substantial revision in the late 18th century. The first objections to this stance were formulated in the eighteenth century by Immanuel Kant who realised that we can say nothing about Substance except through the relation of the subject to other things.

For example: In the sentence "This is a house" the substantive subject "house" only gains meaning in relation to human use patterns or to other similar houses. The category of Substance disappears from Kant's tables, and under the heading of Relation, Kant lists inter alia the three relationship types of Disjunction, Causality and Inherence. The three older concepts of Quantity, Motion and Quality, as Peirce discovered, could be subsumed under these three broader headings in that Quantity relates to the subject through the relation of Disjunction; Motion relates to the subject through the relation of Causality; and Quality relates to the subject through the relation of Inherence. Sets of three continued to play an important part in the nineteenth century development of the categories, most notably in G.W.F. Hegel's extensive tabulation of categories, and in C.S. Peirce's categories set out in his work on the logic of relations. One of Peirce's contributions was to call the three primary categories Firstness, Secondness and Thirdness which both emphasises their general nature, and avoids the confusion of having the same name for both the category itself and for a concept within that category.

In a separate development, and building on the notion of primary and secondary categories introduced by the Scholastics, Kant introduced the idea that secondary or "derivative" categories could be derived from the primary categories through the combination of one primary category with another. This would result in the formation of three secondary categories: the first, "Community" was an example that Kant gave of such a derivative category; the second, "Modality", introduced by Kant, was a term which Hegel, in developing Kant's dialectical method, showed could also be seen as a derivative category; and the third, "Spirit" or "Will" were terms that Hegel and Schopenhauer were developing separately for use in their own systems. Karl Jaspers in the twentieth century, in his development of existential categories, brought the three together, allowing for differences in terminology, as Substantiality, Communication and Will. This pattern of three primary and three secondary categories was used most notably in the nineteenth century by Peter Mark Roget to form the six headings of his Thesaurus of English Words and Phrases. The headings used were the three objective categories of Abstract Relation, Space (including Motion) and Matter and the three subjective categories of Intellect, Feeling and Volition, and he found that under these six headings all the words of the English language, and hence any possible predicate, could be assembled.

Kant

Main article: Category (Kant)

In the Critique of Pure Reason (1781), Immanuel Kant argued that the categories are part of our own mental structure and consist of a set of a priori concepts through which we interpret the world around us. These concepts correspond to twelve logical functions of the understanding which we use to make judgements and there are therefore two tables given in the Critique, one of the Judgements and a corresponding one for the Categories. To give an example, the logical function behind our reasoning from ground to consequence (based on the Hypothetical relation) underlies our understanding of the world in terms of cause and effect (the Causal relation). In each table the number twelve arises from, firstly, an initial division into two: the Mathematical and the Dynamical; a second division of each of these headings into a further two: Quantity and Quality, and Relation and Modality respectively; and, thirdly, each of these then divides into a further three subheadings as follows.

Table of Judgements Mathematical Quantity Universal Particular Singular Quality Affirmative Negative Infinite Dynamical Relation Categorical Hypothetical Disjunctive Modality Problematic Assertoric Apodictic

Table of Categories Mathematical Quantity Unity Plurality Totality Quality Reality Negation Limitation Dynamical Relation Inherence and Subsistence (substance and accident) Causality and Dependence (cause and effect) Community (reciprocity) Modality Possibility Existence Necessity

Criticism of Kant's system followed, firstly, by Arthur Schopenhauer, who amongst other things was unhappy with the term "Community", and declared that the tables "do open violence to truth, treating it as nature was treated by old-fashioned gardeners", and secondly, by W.T.Stace who in his book The Philosophy of Hegel suggested that in order to make Kant's structure completely symmetrical a third category would need to be added to the Mathematical and the Dynamical. This, he said, Hegel was to do with his category of concept.

Hegel

G.W.F. Hegel in his Science of Logic (1812) attempted to provide a more comprehensive system of categories than Kant and developed a structure that was almost entirely triadic. So important were the categories to Hegel that he claimed the first principle of the world, which he called the "absolute", is "a system of categories ... the categories must be the reason of which the world is a consequent".

Using his own logical method of sublation, later called the Hegelian dialectic, reasoning from the abstract through the negative to the concrete, he arrived at a hierarchy of some 270 categories, as explained by W. T. Stace. The three very highest categories were "logic", "nature" and "spirit". The three highest categories of "logic", however, he called "being", "essence", and "notion" which he explained as follows:

• Being was differentiated from Nothing by containing with it the concept of the "other", an initial internal division that can be compared with Kant's category of disjunction. Stace called the category of Being the sphere of common sense containing concepts such as consciousness, sensation, quantity, quality and measure.
• Essence. The "other" separates itself from the "one" by a kind of motion, reflected in Hegel's first synthesis of "becoming". For Stace this category represented the sphere of science containing within it firstly, the thing, its form and properties; secondly, cause, effect and reciprocity, and thirdly, the principles of classification, identity and difference.
• Notion. Having passed over into the "Other" there is an almost neoplatonic return into a higher unity that in embracing the "one" and the "other" enables them to be considered together through their inherent qualities. This according to Stace is the sphere of philosophy proper where we find not only the three types of logical proposition: disjunctive, hypothetical, and categorical but also the three transcendental concepts of beauty, goodness and truth.

Schopenhauer's category that corresponded with "notion" was that of "idea", which in his Four-Fold Root of Sufficient Reason he complemented with the category of the "will". The title of his major work was The World as Will and Idea. The two other complementary categories, reflecting one of Hegel's initial divisions, were those of Being and Becoming. At around the same time, Goethe was developing his colour theories in the Farbenlehre of 1810, and introduced similar principles of combination and complementation, symbolising, for Goethe, "the primordial relations which belong both to nature and vision". Hegel in his Science of Logic accordingly asks us to see his system not as a tree but as a circle.

Twentieth-century development

In the twentieth century the primacy of the division between the subjective and the objective, or between mind and matter, was disputed by, among others, Bertrand Russell and Gilbert Ryle. Philosophy began to move away from the metaphysics of categorisation towards the linguistic problem of trying to differentiate between, and define, the words being used. Ludwig Wittgenstein’s conclusion was that there were no clear definitions which we can give to words and categories but only a "halo" or "corona" of related meanings radiating around each term. Gilbert Ryle thought the problem could be seen in terms of dealing with "a galaxy of ideas" rather than a single idea, and suggested that category mistakes are made when a concept (e.g. "university"), understood as falling under one category (e.g. abstract idea), is used as though it falls under another (e.g. physical object). With regard to the visual analogies being used, Peirce and Lewis, just like Plotinus earlier, likened the terms of propositions to points, and the relations between the terms to lines. Peirce, taking this further, talked of univalent, bivalent and trivalent relations linking predicates to their subject and it is just the number and types of relation linking subject and predicate that determine the category into which a predicate might fall. Primary categories contain concepts where there is one dominant kind of relation to the subject. Secondary categories contain concepts where there are two dominant kinds of relation. Examples of the latter were given by Heidegger in his two propositions "the house is on the creek" where the two dominant relations are spatial location (Disjunction) and cultural association (Inherence), and "the house is eighteenth century" where the two relations are temporal location (Causality) and cultural quality (Inherence). A third example may be inferred from Kant in the proposition "the house is impressive or sublime" where the two relations are spatial or mathematical disposition (Disjunction) and dynamic or motive power (Causality). Both Peirce and Wittgenstein introduced the analogy of colour theory in order to illustrate the shades of meanings of words. Primary categories, like primary colours, are analytical representing the furthest we can go in terms of analysis and abstraction and include Quantity, Motion and Quality. Secondary categories, like secondary colours, are synthetic and include concepts such as Substance, Community and Spirit.

Apart from these, the categorial scheme of Alfred North Whitehead and his Process Philosophy, alongside Nicolai Hartmann and his Critical Realism, remain one of the most detailed and advanced systems in categorial research in metaphysics.

Peirce

Main article: Categories (Peirce)

Charles Sanders Peirce, who had read Kant and Hegel closely, and who also had some knowledge of Aristotle, proposed a system of merely three phenomenological categories: Firstness, Secondness, and Thirdness, which he repeatedly invoked in his subsequent writings. Like Hegel, C.S. Peirce attempted to develop a system of categories from a single indisputable principle, in Peirce's case the notion that in the first instance he could only be aware of his own ideas. "It seems that the true categories of consciousness are first, feeling ... second, a sense of resistance ... and third, synthetic consciousness, or thought". Elsewhere he called the three primary categories: Quality, Reaction and Meaning, and even Firstness, Secondness and Thirdness, saying, "perhaps it is not right to call these categories conceptions, they are so intangible that they are rather tones or tints upon conceptions":

• Firstness (Quality): "The first is predominant in feeling ... we must think of a quality without parts, e.g. the colour of magenta ... When I say it is a quality I do not mean that it "inheres" in a subject ... The whole content of consciousness is made up of qualities of feeling, as truly as the whole of space is made up of points, or the whole of time by instants".
• Secondness (Reaction): "This is present even in such a rudimentary fragment of experience as a simple feeling ... an action and reaction between our soul and the stimulus ... The idea of second is predominant in the ideas of causation and of statical force ... the real is active; we acknowledge it by calling it the actual".
• Thirdness (Meaning): "Thirdness is essentially of a general nature ... ideas in which thirdness predominate [include] the idea of a sign or representation ... Every genuine triadic relation involves meaning ... the idea of meaning is irreducible to those of quality and reaction ... synthetical consciousness is the consciousness of a third or medium".

Although Peirce's three categories correspond to the three concepts of relation given in Kant's tables, the sequence is now reversed and follows that given by Hegel, and indeed before Hegel of the three moments of the world-process given by Plotinus. Later, Peirce gave a mathematical reason for there being three categories in that although monadic, dyadic and triadic nodes are irreducible, every node of a higher valency is reducible to a "compound of triadic relations". Ferdinand de Saussure, who was developing "semiology" in France just as Peirce was developing "semiotics" in the US, likened each term of a proposition to "the centre of a constellation, the point where other coordinate terms, the sum of which is indefinite, converge".

Others

Edmund Husserl (1962, 2000) wrote extensively about categorial systems as part of his phenomenology.

For Gilbert Ryle (1949), a category (in particular a "category mistake") is an important semantic concept, but one having only loose affinities to an ontological category.

Contemporary systems of categories have been proposed by John G. Bennett (The Dramatic Universe, 4 vols., 1956–65), Wilfrid Sellars (1974), Reinhardt Grossmann (1983, 1992), Johansson (1989), Hoffman and Rosenkrantz (1994), Roderick Chisholm (1996), Barry Smith (ontologist) (2003), and Jonathan Lowe (2006).

World domination

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/World_domination

World domination (also called global domination or world conquest or cosmocracy) is a hypothetical power structure, either achieved or aspired to, in which a single political authority holds the power over all or virtually all the inhabitants of Earth. Various individuals or regimes have tried to achieve this goal throughout history, without ever attaining it. The theme has been often used in works of fiction, particularly in political fiction, as well as in conspiracy theories (which may posit that some person or group has already secretly achieved this goal), particularly those fearing the development of a "New World Order" involving a world government of a totalitarian nature.

History

Main article: List of largest empires

The British Empire at its territorial peak in 1921

While various empires over the course of history have been able to expand and dominate large parts of the world, none have come close to conquering all the territory on Earth. However, these empires have had a global impact in cultural and economic terms that is still felt today. Some of the largest and more prominent empires include:

• The Mongol Empire, which in the 13th century under Genghis Khan came to control the largest continuous land empire in the world, spanning from East Asia to the Middle East and Eastern Europe. It eventually fractured and ended with the fall of the Yuan dynasty, which was established by Kublai Khan. It reached its greatest extent in 1309, when it controlled the region through which the Silk Road trade route ran. Ensuring the stability of this trade route enabled commerce across Eurasia, accelerating the pace of economic and technological development around the world.
• The British Empire, originating under Elizabeth I, was the largest empire in history. By 1921, the British Empire reached its height and dominated a quarter of the globe, controlling territory on each continent. The empire went through a long period of decline and decolonization following the end of the Second World War, which had brought it close to bankruptcy, until it ceased to be a dominant force in world affairs. English is still the official language in many countries, most of which were former British colonies, and is widely spoken as a second language around the world. The Industrial Revolution that took place in the United Kingdom from the 18th century was spread to the rest of the globe through the expansion of the British Empire, enabling the development of an industrialized global economy.
• The Russian Empire, which controlled vast areas of Eurasia stretching from the Baltic region to Russian Manchuria, reaching its largest extent in 1895. The empire collapsed during the February Revolution in 1917, which saw Tsar Nicholas II abdicate. The cultural and economic unity of the Russian Empire allowed the rise of its successor state, the Soviet Union, a superpower whose military strength and ideology were major forces in global politics during the 20th century. After the collapse of the Soviet Union in 1991, the Russian Federation remains one of the few nations to pursue its goals through territorial conquest in the 21st century.

• 

  Charles I of Spain and V of the Holy Roman Empire with an allegation of being a Universal monarch who was near to the Dominium mundi.

  The Spanish Empire under the Habsburg monarchy and Iberian Union, which controlled vast areas of Europe, America, Africa and some parts of Asia. The empire collapsed in a process that started in the Thirty Years' War and the Napoleonic Wars. It was the first global empire in human history, being the first one who was referred to as The empire on which the sun never sets and having pretensions (specially during the Spanish Habsburg) to being the secular leaders of the worldwide Christendom and the sword of the Pope against their opponents, the Protestant Reformers on Northern Europe, the Regalism from Kingdom of France, the Islamic world on Greater Middle East (mostly Ottoman Empire on Western Asia and Morocco of North Africa), the Pagans from the West Indies and East Indies, and all the enemies of the Catholic Church in their Christian mission to Evangelise all the World.

By the early 21st century, wars of territorial conquest were uncommon and the world's nations could attempt to resolve their differences through multilateral diplomacy under the auspices of global organizations like the United Nations and World Trade Organization. The world's superpowers and potential superpowers rarely attempt to exert global influence through the types of territorial empire-building seen in history, but the influence of historical empires is still important and the idea of world domination is still socially and culturally relevant.

Social and political ideologies

Main article: World government

By 500 BC, Darius the Great had created the largest empire up until that time, but it was still only a fraction of the land and people of the Earth (controlling near half population of the entire world).

Historically, world domination has been thought of in terms of a nation expanding its power to the point that all other nations are subservient to it. This may be achieved by establishing a hegemony, an indirect form of government and of imperial dominance in which the hegemon (leading state) controls geopolitically subordinate states by means of its implied power—by the threat of force, rather than by direct military force. However, domination can also be achieved by direct military force.

The title of King of the Universe appeared in Ancient Mesopotamia as a title of great prestige claiming world domination, being used by powerful monarchs, starting with the Akkadian emperor Sargon (2334–2284 BC) and it was used in a succession of later empires claiming symbolical descent from Sargon's Akkadian Empire. During the Early Dynastic Period in Mesopotamia (c. 2900–2350 BC), the rulers of the various city-states (the most prominent being Ur, Uruk, Lagash, Umma and Kish) in the region would often launch invasions into regions and cities far from their own, at most times with negligible consequences for themselves, in order to establish temporary and small empires to either gain or keep a superior position relative to the other city-states. Eventually this quest to be more prestigious and powerful than the other city-states resulted in a general ambition for universal rule. Since Mesopotamia was equated to correspond to the entire world and Sumerian cities had been built far and wide (cities the like of Susa, Mari and Assur were located near the perceived corners of the world) it seemed possible to reach the edges of the world (at this time thought to be the lower sea, the Persian gulf, and the upper sea, the Mediterranean).

The title šar kiššatim was perhaps most prominently used by the kings of the Neo-Assyrian Empire, more than a thousand years after the fall of the Akkadian Empire.

After taking Babylon and defeat the Neo-Babylonian Empire, Cyrus the Great proclaimed himself "king of Babylon, king of Sumer and Akkad, king of the four corners of the world" in the famous Cyrus Cylinder, an inscription deposited in the foundations of the Esagila temple dedicated to the chief Babylonian god, Marduk. Cyrus the Great's dominions composed the largest empire the world had ever seen to that point, spanning from the Mediterranean Sea and Hellespont in the west to the Indus River in the east and Iranian philosophy, literature and religion played dominant roles in world events for the next millennium, like the Cyrus Cylinder as the oldest-known declaration of human rights. Before Cyrus and his army crossed the river Araxes to battle with the Armenians, he installed his son Cambyses II as king in case he should not return from battle. However, once Cyrus had crossed the Aras River, he had a vision in which Darius had wings atop his shoulders and stood upon the confines of Europe and Asia (the known world). When Cyrus awoke from the dream, he inferred it as a great danger to the future security of the empire, as it meant that Darius would one day rule the whole world. However, his son Cambyses was the heir to the throne, not Darius, causing Cyrus to wonder if Darius was forming treasonable and ambitious designs. This led Cyrus to order Hystaspes to go back to Persis and watch over his son strictly, until Cyrus himself returned. In many cuneiform inscriptions, like Behistun Inscription, Darius the Great denote his achievements, he presents himself as a devout believer of Ahura Mazda, perhaps even convinced that he had a divine right to rule over the world, believing that because he lived righteously by Asha, Ahura Mazda supported him as a Virtuos monarch and appointed him to rule the Achaemenid Empire and their global projection, while believing that each rebellion in his kingdom was the work of druj, the enemy of Asha, due to Dualist beliefs.

In the 4th century BCE, Alexander the Great notably expressed a desire to conquer the world, and a legend persists that after he completed his military conquest of the known ancient world, he "wept because he had no more worlds to conquer", as he was unaware of China farther to the east and had no way to know about civilizations in the Americas.

After the collapse of Macedonian Empire, the Seleucid Empire appeared with claims to world rule in their imperial ideology, as Antiochus I Soter claimed the ancient Mesopotamian title King of the Universe. However, it didn't reflect realistic Seleucid imperial ambitions at this point after the treaty of peace of Seleucus I Nicator with the Mauryans had set a limit to eastern expansion, and Antiochus ceding the lands west of Thrace to the Antigonids.

On the Indosphere, Bharata Chakravartin was the first chakravartin (universal emperor, ruler of rulers or possessor of chakra) of Avasarpini (present half time cycle as per Jain cosmology). In a Jain legend, Yasasvati Devi, senior-most queen of Rishabhanatha (first Jain tirthankara), saw four auspicious dreams one night. She saw the sun and the moon, the Mount Meru, the lake with swans, earth and the ocean. Rishabhanatha explained her that these dreams meant that a chakravartin ruler will be born to them who will conquer whole of the world. Then, Bharata, a Kshatriya from Ikshvaku dynasty, was born to them on the ninth day of the dark half of the month of Chaitra. He is said to have conquered all the six parts of the world, during his digvijaya (winning six divisions of earth in all directions), and to have engaged in a fight with Bahubali, his brother, to conquer the last remaining city. The ancient name of India was named "Bhāratavarsha" or "Bhārata" or "Bharata-bhumi" after him. In the Hindu text, Skanda Purana (chapter 37) it is stated that "Rishabhanatha was the son of Nabhiraja, and Rishabha had a son named Bharata, and after the name of this Bharata, this country is known as Bharata-varsha." After completing his world-conquest, he is said to have proceeded for his capital Ayodhyapuri with a huge army and the divine chakra-ratna (spinning, disk-like super weapon with serrated edges). Also, there's a legend of the Maharaj Vikramaditya's Empire, which spread across Middle East and East Asia (reaching even modern Indonesia) as a great Hindu world emperor (Chakravarti), probably inspiring the imperial pretensions of Chandragupta II and Skandagupta, as the term Vikramaditya is also used as a title by several Hindu monarchs. According to P.N. Oak and Stephen Knapp, king Vikrama’s empire extended up to Europe and whole Jambudweep (Asia) . But, according to most historical texts, his kingdom was located in the present-day northern India and Pakistan, implying that the historic Vikramaditya only ruled on Bharat until River Indus as per Bhavishya Purana. So, there is no epigraphic evidence to suggest that his rule extended to Europe, Arabia, Central Asia or Southeast Asia (Sources of contemporary empires, like Parthians, Kushans, Chinese, Romans, Sassanids) don't mention an empire ruling from Arabia to Indonesia), and that part of his rule is considered to be legend rather than historical fact, lying in the fact that Indic religious conceptions of the Indian sub-continent as being "the world" (as how the term Jambudvipa is used broadly to the same), and how that translates into folk memories. However, the Mahabharata or Somadeva's Kathasaritasagara has pretensions of world ruling, as performing some mystic ritual and virtues would be a signal of becoming emperor of the whole world, as Dharma has a universal jurisdiction in all the cosmos. In which there was a time when King Yudhisthira ruled over "the world". As From Śuciratha will come the son named Vṛṣṭimān, and his son, Suṣeṇa, will be the emperor of the entire world. Also there are signs in Bāṇabhaṭṭa that will shall arise an emperor named Harsha, who will rule over all the continents like Harishchandra, who will conquer the world like Mandhatr. But, the world, in the time of Ramayana in the 12th millennium BCE and Mahabharata in the 5th millennium BCE was only India. Some pan-indian empires, like Maurya Empire, were seeking the world domination (first of the known ancient world by indian in the Akhand Bharat, and then enter in conflict with Seleucid Empire), as Ashoka the great was a devout Buddhist and wanted to stablish it as a world religion. Also, the first references to a Chakravala Chakravartin (an emperor who rules over all four of the continents) appear in monuments from the time of the early Maurya Empire, in the 4th to 3rd century BCE, in reference to Chandragupta Maurya and his grandson Ashoka.

On the Sinosphere, one of the consequences of the Mandate of Heaven in Imperial China was the claim of the Emperor of China as Son of Heaven who ruled tianxia (meanint "all under heaven", closely associated with civilization and order in classical Chinese philosophy), which in English can be transliterated as "ruler of the whole world", being equivalent to the concept of a universal monarch. The title was interpreted literally only in China and Japan, whose monarchs were referred to as demigods, deities, or "living gods", chosen by the gods and goddesses of heaven. The theory, from Confucian bureaucracy, behind this was that the Chinese emperor acted as the autocrat of all under Heaven and held a mandate to rule over everyone else in the world; but only as long as he served the people well. If the quality of rule became questionable because of repeated natural disasters such as flood or famine, or for other reasons, then rebellion was justified. This important concept legitimized the dynastic cycle or the change of dynasties. The center of this world view was not exclusionary in nature, and outer groups, such as ethnic minorities and foreign people, who accepted the mandate of the Chinese Emperor (through annexation or being Tributary state of China) were themselves received and included into the Chinese tianxia (in which equates China as "everything under the sky"), as it presupposed "inclusion of all" and implied acceptance of the world's diversities, emphasizing harmonious reciprocal dependence and ruled by virtue as a means for lasting peace. Although in practice there would be areas of the known world which were not under the control of the Chinese monarch ("barbarians"), in Chinese political theory the rulers of those areas derived their power from the Chinese monarch (Sinocentrism). This principle was exemplified with Qin Shi Huang's goal to "unify all under Heaven", which was, in fact, representative of his desire to control and expand Chinese territory to act as an actual geographic entity, as consecuence of existing many of feudal states that had shared cultural and economic interests, so the concept of a great nation centered on the Yellow River Plain (the known world, both Han or Non-Han in Hua–Yi distinction) gradually expanded and the equivalence of tianxia with the Chinese nation evolved due to the feudal practice of conferring land. For the emperors of the central kingdom of China, the world can be roughly divided into two broad and simple categories: civilization and non-civilization, which means the people who have accepted the emperor's supremacy, the Heavenly virtue and its principle, and the people who have not accepted it; then, they recognized their country as the only true civilization in all respects, starting with their geography and including all the known world in a Celestial Empire. China's neighbors were obliged to pay their respects to the 'excellent' Chinese emperors within these boundaries on a regular basis. It can be said that this was the most important element of the East Asian order, which was implicit in the name of Celestial Empire in the past. In the 7th century during the Tang dynasty, some northern tribes of Turkic origin, after being made vassal (as consecuence of Tang campaign against the Eastern Turks), referred to the Emperor Taizong as the "Khan of Heaven". Also The Chinese emperor exercised power over the surrounding dynasty under the name of Celestial Empire. Especially in the case of kings of ancient Korea, it was the subject of the Chinese emperor. The idea of the absolute authority of the Chinese emperor and the extension of tianxia by the assimilation of vassal states began to fade with the Opium Wars, as China was made to refer to Great Britain as a "sovereign nation", equal to itself, it to establish a foreign affairs bureau and accommodate to Westphalian sovereignty of Western nations' system of international affairs during New Imperialism.

On Sasanian Empire, the use of the mythological Kayanian title of kay, first used by Yazdegerd II and reached its zenith under Peroz I, was due to a shift in the political perspective of the Sasanian Empire. Originally disposed towards the west against their rivals from the Byzantine Empire, this now changed to the east against Hephthalites. The war against the Hunnic tribes (Iranian Huns) may have awakened the mythical rivalry existing between the Iranian Kayanian rulers (mythical kings of the legendary Avestan dynasty) and their Turanian enemies, which is demonstrated in the Younger Avesta. Based on the legend of the Iranian hero-king Fereydun (Frēdōn in Middle Persian), who divided his kingdom between his three sons: his eldest son Salm received the empire of the west, "Rûm" (more generally meaning the Roman Empire, the Greco-Roman world, or just "the West"); the second eldest Tur received the empire of the east, Turān (all the lands north and east of the Amu Darya, as far as China); and the youngest, Iraj, received the heartland of the empire, Iran. So, the Sasanians Shahanshah may have believed themselves to be the heirs of the Fereydun and Iraj (reinforced because they were Ahura Mazda's worshippers), and so possibly considered both the Byzantine domains in west and the eastern domains of the Hephthalites as belonging to Iran, and therefore have been symbolically asserting their rights over these lands of both Hemispheres of Earth by assuming the title of kay.

On the Mongol Empire, Genghis Khan genuinely believed that it was his destiny to conquer the world for his god, Tengri, having a mission of bringing the rest of the world under one sword. This was based in his shamanic beliefs of the Great Blue Sky that spans the world, deriving his mandate for a world empire from this universal divinity, being close to unify Eurasia into a world empire under the shamanic umbrella. Also, Temujin took name "Genghis Khan", which means Universal Ruler, then, his sons and grandsons took up challenge of world conquest.

The fourth Mughal emperor styled himself Jahangir, meaning "world conqueror", and her wife Mehr-un-Nissa being awarded with the title of Nur Jahan ('Light of the World').

The Ottoman Empire had claims of world domination through Ottoman Caliphate. The Süleyman the Magnificent's Venetian helmet was an elaborate headpiece designed to project the sultan's power in the context of the Ottoman–Habsburg rivalry. Meaning The four floors of the Crown also represent Solomon's goal of world conquest—reigning the North, the South, the East, and the West—as well as the Pope's famous triple crown and the Holy Roman Empire two years ago. It was a reference to Charles V, who was crowned as the German Emperor, and also the three-tiered tiara worn by the Pope Clement VII.

However, with the full size and scope of the world known, it has been said that "world domination is an impossible goal", and specifically that "no single nation however big and powerful can dominate a world" of well over a hundred interdependent nations and billions of people.

An opposite view was expressed by Hans Morgenthau in 1948. He stressed that the mechanical development of weapons, transportation, and communication makes "the conquest of the world technically possible, and they make it technically possible to keep the world in that conquered state." He argues that a lack of such infrastructure explains why great ancient empires, though vast, failed to complete the universal conquest of their world and perpetuate the conquest. "Today no technological obstacle stands in the way of a world-wide empire," as "modern technology makes it possible to extend the control of mind and action to every corner of the globe regardless of geography and season." Morgenthau continued on the technological progress:

It has also given total war that terrifying, world-embracing impetus which seems to be satisfied with nothing less than world dominion... The machine age begets its own triumphs, each forward step calling forth two or more on the road of technological progress. It also begets its own victories, military and political; for with the ability to conquer the world and keep it conquered, it creates the will to conquer it.

In the early 17th century, Sir Walter Raleigh proposed that world domination could be achieved through control of the oceans, writing that "whosoever commands the sea commands the trade; whosoever commands the trade of the world commands the riches of the world, and consequently the world itself". In 1919, Halford Mackinder offered another influential theory for a route to world domination, writing:

Who rules East Europe commands the Heartland;
Who rules the Heartland commands the World-Island;
Who rules the World-Island commands the World.

While Mackinder's "Heartland Theory" initially received little attention outside geography, it later exercised some influence on the foreign policies of world powers seeking to obtain the control suggested by the theory. Impressed with the swift opening of World War II, Derwent Whittlesey wrote in 1942:

The swift march of conquest stunned or dazzled the onlookers... The grandiose concept of the world domination became possible as a practical objective only with the rise of science and its application to mechanical invention. By these means the earth’s scattered land units and territories became accessible and complementary to each other, and for the first time the world state, so long a futile medieval ideal, became a goal that might conceivably be reached.

Yet before the entrance of the United States into this War and with Isolationism still intact, U.S. strategist Hanson W. Baldwin had projected that "[t]omorrow air bases may be the highroad to power and domination... Obviously it is only by air bases ... that power exercised in the sovereign skies above a nation can be stretched far beyond its shores... Perhaps... future acquisitions of air bases ... can carry the voice of America through the skies to the ends of the earth.

Some proponents of ideologies (communism, fascism, Nazism, and socialism) actively pursue the goal of establishing a form of government consistent with their political beliefs, or assert that the world is moving "naturally" towards the adoption of a particular form of government (or self), authoritarian or anti-authoritarian. These proposals are not concerned with a particular nation achieving world domination, but with all nations conforming to a particular social or economic model. A goal of world domination can be to establish a world government, a single common political authority for all of humanity. The period of the Cold War, in particular, is considered to be a period of intense ideological polarization, given the existence of two rival blocs—the capitalist West and the communist East—that each expressed the hope of seeing the triumph of their ideology over that of the enemy. The ultimate end of such a triumph would be that one ideology or the other would become the sole governing ideology in the world.

In certain religions, some adherents may also seek the conversion (peaceful or forced) of as many people as possible to their own religion, without restrictions of national or ethnic origin. This type of spiritual domination is usually seen as distinct from the temporal dominion, although there have been instances of efforts begun as holy wars devolving into the pursuit of wealth, resources, and territory. Some Christian groups teach that a false religion, led by false prophets who achieve world domination by inducing nearly universal worship of a false deity, is a prerequisite to end times described in the Book of Revelation. As one author put it, "[i]f world domination is to be obtained, the masses of little people must be brought on board with religion".

In some instances, speakers have accused nations or ideological groups of seeking world domination, even where those entities have denied that this was their goal. For example, J. G. Ballard quoted Aldous Huxley as having said of the United States entering the First World War, "I dread the inevitable acceleration of American world domination which will be the result of it all...Europe will no longer be Europe". In 2012, politician and critic of Islam Geert Wilders characterized Islam as "an ideology aiming for world domination rather than a religion", and in 2008 characterized the 2008 Israel–Gaza conflict as a proxy action by Islam against the West, contending that "[t]he end of Israel would not mean the end of our problems with Islam, but only... the start of the final battle for world domination".

Passive cooling

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Passive_cooling

A traditional Iranian solar cooling design using a wind tower

Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from entering the interior (heat gain prevention) or by removing heat from the building (natural cooling).

Natural cooling utilizes on-site energy, available from the natural environment, combined with the architectural design of building components (e.g. building envelope), rather than mechanical systems to dissipate heat. Therefore, natural cooling depends not only on the architectural design of the building but on how the site's natural resources are used as heat sinks (i.e. everything that absorbs or dissipates heat). Examples of on-site heat sinks are the upper atmosphere (night sky), the outdoor air (wind), and the earth/soil.

Passive cooling is an important tool for design of buildings for climate change adaptation – reducing dependency on energy-intensive air conditioning in warming environments.

Overview

Passive cooling covers all natural processes and techniques of heat dissipation and modulation without the use of energy. Some authors consider that minor and simple mechanical systems (e.g. pumps and economizers) can be integrated in passive cooling techniques, as long they are used to enhance the effectiveness of the natural cooling process. Such applications are also called 'hybrid cooling systems'. The techniques for passive cooling can be grouped in two main categories:

• Preventive techniques that aim to provide protection and/or prevention of external and internal heat gains.
• Modulation and heat dissipation techniques that allow the building to store and dissipate heat gain through the transfer of heat from heat sinks to the climate. This technique can be the result of thermal mass or natural cooling.

Preventive techniques

This ancient Roman house avoids gaining heat. Heavy masonry walls, small exterior windows, and a narrow walled garden oriented N-S shade the house, preventing heat gain. The house opens onto a central atrium with an impluvium (open to the sky); the evaporative cooling of the water causes a cross-draft from atrium to garden.

Protection from or prevention of heat gains encompasses all the design techniques that minimizes the impact of solar heat gains through the building's envelope and of internal heat gains that is generated inside the building due occupancy and equipment. It includes the following design techniques:

• Microclimate and site design - By taking into account the local climate and the site context, specific cooling strategies can be selected to apply which are the most appropriate for preventing overheating through the envelope of the building. The microclimate can play a huge role in determining the most favorable building location by analyzing the combined availability of sun and wind. The bioclimatic chart, the solar diagram and the wind rose are relevant analysis tools in the application of this technique.
• Solar control - A properly designed shading system can effectively contribute to minimizing the solar heat gains. Shading both transparent and opaque surfaces of the building envelope will minimize the amount of solar radiation that induces overheating in both indoor spaces and building's structure. By shading the building structure, the heat gain captured through the windows and envelope will be reduced.
• Building form and layout - Building orientation and an optimized distribution of interior spaces can prevent overheating. Rooms can be zoned within the buildings in order to reject sources of internal heat gain and/or allocating heat gains where they can be useful, considering the different activities of the building. For example, creating a flat, horizontal plan will increase the effectiveness of cross-ventilation across the plan. Locating the zones vertically can take advantage of temperature stratification. Typically, building zones in the upper levels are warmer than the lower zones due to stratification. Vertical zoning of spaces and activities uses this temperature stratification to accommodate zone uses according to their temperature requirements. Form factor (i.e. the ratio between volume and surface) also plays a major role in the building's energy and thermal profile. This ratio can be used to shape the building form to the specific local climate. For example, more compact forms tend to preserve more heat than less compact forms because the ratio of the internal loads to envelope area is significant.
• Thermal insulation - Insulation in the building's envelope will decrease the amount of heat transferred by radiation through the facades. This principle applies both to the opaque (walls and roof) and transparent surfaces (windows) of the envelope. Since roofs could be a larger contributor to the interior heat load, especially in lighter constructions (e.g. building and workshops with roof made out of metal structures), providing thermal insulation can effectively decrease heat transfer from the roof.
• Behavioral and occupancy patterns - Some building management policies such as limiting the number of people in a given area of the building can also contribute effectively to the minimization of heat gains inside a building. Building occupants can also contribute to indoor overheating prevention by: shutting off the lights and equipment of unoccupied spaces, operating shading when necessary to reduce solar heat gains through windows, or dress lighter in order to adapt better to the indoor environment by increasing their thermal comfort tolerance.
• Internal gain control - More energy-efficient lighting and electronic equipment tend to release less energy thus contributing to less internal heat loads inside the space.

Modulation and heat dissipation techniques

The modulation and heat dissipation techniques rely on natural heat sinks to store and remove the internal heat gains. Examples of natural sinks are night sky, earth soil, and building mass. Therefore, passive cooling techniques that use heat sinks can act to either modulate heat gain with thermal mass or dissipate heat through natural cooling strategies.

• Thermal mass - Heat gain modulation of an indoor space can be achieved by the proper use of the building's thermal mass as a heat sink. The thermal mass will absorb and store heat during daytime hours and return it to the space at a later time. Thermal mass can be coupled with night ventilation natural cooling strategy if the stored heat that will be delivered to the space during the evening/night is not desirable.
• Natural cooling - Natural cooling refers to the use of ventilation or natural heat sinks for heat dissipation from indoor spaces. Natural cooling can be separated into five different categories: ventilation, night flushing, radiative cooling, evaporative cooling, and earth coupling.

Ventilation

A pair of short windcatchers (malqaf) used in traditional architecture; wind is forced down on the windward side and leaves on the leeward side (cross-ventilation). In the absence of wind, the circulation can be driven with evaporative cooling in the inlet. In the center, a shuksheika (roof lantern vent), used to shade the qa'a below while allowing hot air rise out of it (stack effect).

Ventilation as a natural cooling strategy uses the physical properties of air to remove heat or provide cooling to occupants. In select cases, ventilation can be used to cool the building structure, which subsequently may serve as a heat sink.

• Cross ventilation - The strategy of cross ventilation relies on wind to pass through the building for the purpose of cooling the occupants. Cross ventilation requires openings on two sides of the space, called the inlet and outlet. The sizing and placement of the ventilation inlets and outlets will determine the direction and velocity of cross ventilation through the building. Generally, an equal (or greater) area of outlet openings must also be provided to provide adequate cross ventilation.
• Stack ventilation - Cross ventilation is an effective cooling strategy, however, wind is an unreliable resource. Stack ventilation is an alternative design strategy that relies on the buoyancy of warm air to rise and exit through openings located at ceiling height. Cooler outside air replaces the rising warm air through carefully designed inlets placed near the floor.

These two strategies are part of the ventilative cooling strategies.

One specific application of natural ventilation is night flushing.

Night flushing

A courtyard in Florence, Italy. It is tall and narrow, with a fountain spouting very thin streams of water at the bottom, and upper rooms opening onto it. Night flushing of the courtyard happens automatically as the night air cools; evaporative cooling cools it further and can be used to create drafts and change the air during the day. Windows can be left open around the clock.

Night flushing (also known as night ventilation, night cooling, night purging, or nocturnal convective cooling) is a passive or semi-passive cooling strategy that requires increased air movement at night to cool the structural elements of a building. A distinction may be made between free cooling to chill water and night flushing to cool down building thermal mass. To execute night flushing, one typically keeps the building envelope closed during the day. The building structure's thermal mass acts as a sink through the day and absorbs heat gains from occupants, equipment, solar radiation, and conduction through walls, roofs, and ceilings. At night, when the outside air is cooler, the envelope is opened, allowing cooler air to pass through the building so the stored heat can be dissipated by convection. This process reduces the temperature of the indoor air and of the building's thermal mass, allowing convective, conductive, and radiant cooling to take place during the day when the building is occupied. Night flushing is most effective in climates with a large diurnal swing, i.e. a large difference between the daily maximum and minimum outdoor temperature. For optimal performance, the nighttime outdoor air temperature should fall well below the daytime comfort zone limit of 22 °C (72 °F), and should not have low absolute or specific humidity. In hot, humid climates the dirunal temperature swing is typically small, and the nighttime humidity stays high. Night flushing has limited effectiveness and can introduce high humidity that causes problems and can lead to high energy costs if it is removed by active systems during the day. Thus, night flushing's effectiveness is limited to sufficiently dry climates. For the night flushing strategy to be effective at reducing indoor temperature and energy usage, the thermal mass must be sized sufficiently and distributed over a wide enough surface area to absorb the space's daily heat gains. Also, the total air change rate must be high enough to remove the internal heat gains from the space at night. There are three ways night flushing can be achieved in a building:

• Natural night flushing by opening windows at night, letting wind-driven or buoyancy-driven airflow cool the space, and then closing windows during the day.
• Mechanical night flushing by forcing air mechanically through ventilation ducts at night at a high airflow rate and supplying air to the space during the day at a code-required minimum airflow rate.
• Mixed-mode night flushing through a combination of natural ventilation and mechanical ventilation, also known as mixed-mode ventilation, by using fans to assist the natural nighttime airflow.

These three strategies are part of the ventilative cooling strategies.

There are numerous benefits to using night flushing as a cooling strategy for buildings, including improved comfort and a shift in peak energy load.^[22] Energy is most expensive during the day. By implementing night flushing, the usage of mechanical ventilation is reduced during the day, leading to energy and money savings.

There are also a number of limitations to using night flushing, such as usability, security, reduced indoor air quality, humidity, and poor room acoustics. For natural night flushing, the process of manually opening and closing windows every day can be tiresome, especially in the presence of insect screens. This problem can be eased with automated windows or ventilation louvers, such as in the Manitoba Hydro Place. Natural night flushing also requires windows to be open at night when the building is most likely unoccupied, which can raise security issues. If outdoor air is polluted, night flushing can expose occupants to harmful conditions inside the building. In loud city locations, the opening of windows can create poor acoustical conditions inside the building. In humid climates, night flushing can introduce humid air, typically above 90% relative humidity during the coolest part of the night. This moisture can accumulate in the building overnight leading to increased humidity during the day leading to comfort problems and even mold growth.

Radiative cooling

Main article: Radiative cooling

The infrared atmospheric window, frequencies in which the atmosphere is unusually transparent, is the large blueish block on the right. An object that is fluorescent in these wavelengths can cool itself to below ambient air temperature.

Radiative cooling energy budget in a yakhchāl.

All objects constantly emit and absorb radiant energy. An object will cool by radiation if the net flow is outward, which is the case during the night. At night, the long-wave radiation from the clear sky is less than the long-wave infrared radiation emitted from a building, thus there is a net flow to the sky. Since the roof provides the greatest surface visible to the night sky, designing the roof to act as a radiator is an effective strategy. Types of radiative cooling strategies that utilize the roof surface include direct and indirect, and fluorescent.

• Direct radiant cooling - In a building designed to optimize direct radiation cooling, the building roof acts as a heat sink to absorb the daily internal loads. The roof acts as the best heat sink because it is the greatest surface exposed to the night sky. Radiate heat transfer with the night sky will remove heat from the building roof, thus cooling the building structure. Roof ponds are an example of this strategy. The roof pond design became popular with the development of the Sky thermal system designed by Harold Hay in 1977. There are various designs and configurations for the roof pond system but the concept is the same for all designs. The roof uses water, either plastic bags filled with water or an open pond, as the heat sink while a system of movable insulation panels regulate the mode of heating or cooling. During daytime in the summer, the water on the roof is protected from the solar radiation and ambient air temperature by movable insulation, which allows it to serve as a heat sink and absorb the heat generated inside through the ceiling. At night, the panels are retracted to allow nocturnal radiation between the roof pond and the night sky, thus removing the stored heat. In winter, the process is reversed so that the roof pond is allowed to absorb solar radiation during the day and release it during the night into the space below.
• Indirect radiant cooling - A heat transfer fluid removes heat from the building structure through radiate heat transfer with the night sky. A common design for this strategy involves a plenum between the building roof and the radiator surface. Air is drawn into the building through the plenum, cooled from the radiator, and cools the mass of the building structure. During the day, the building mass acts as a heat sink.
• Fluorescent radiant cooling - An object can be made fluorescent: it will then absorb light at some wavelengths, but radiate the energy away again at other, selected wavelengths. By selectively radiating heat in the infrared atmospheric window, a range of frequencies in which the atmosphere is unusually transparent, an object can effectively use outer space as a heat sink, and cool to well below ambient air temperature.

Evaporative cooling

A salasabil (currently dry) in the Red Fort in Delhi, India. A salasabil is designed to maximize evaporative cooling; the cooling, in turn, may be used to drive air circulation.

Main article: Evaporative cooling

This design relies on the evaporative process of water to cool the incoming air while simultaneously increasing the relative humidity. A saturated filter is placed at the supply inlet so the natural process of evaporation can cool the supply air. Apart from the energy to drive the fans, water is the only other resource required to provide conditioning to indoor spaces. The effectiveness of evaporative cooling is largely dependent on the humidity of the outside air; dryer air produces more cooling. A study of field performance results in Kuwait revealed that power requirements for an evaporative cooler are approximately 75% less than the power requirements for a conventional packaged unit air-conditioner. As for interior comfort, a study found that evaporative cooling reduced inside air temperature by 9.6 °C compared to outdoor temperature. An innovative passive system uses evaporating water to cool the roof so that a major portion of solar heat does not come inside.

Ancient Egypt used evaporative cooling; for instance, reeds were hung in windows and were moistened with trickling water.

Evaporation from the soil and transpiration from plants also provides cooling; the water released from the plant evaporates. Gardens and potted plants are used to drive cooling, as in the hortus of a domus, the tsubo-niwa of a machiya, and so on.

Earth coupling

A qanat and windcatcher used as an earth duct, for both earth coupling and evaporative cooling. No fan is needed; the suction in the lee of the windtower draws the air up and out.

Main article: Ground-coupled heat exchanger

Earth coupling uses the moderate and consistent temperature of the soil to act as a heat sink to cool a building through conduction. This passive cooling strategy is most effective when earth temperatures are cooler than ambient air temperature, such as in hot climates.

• Direct coupling or earth sheltering occurs when a building uses earth as a buffer for the walls. The earth acts as a heat sink and can effectively mitigate temperature extremes. Earth sheltering improves the performance of building envelopes by reducing heat losses and also reduces heat gains by limiting infiltration.
• Indirect coupling means that a building is coupled with the earth by means of earth ducts. An earth duct is a buried tube that acts as avenue for supply air to travel through before entering the building. The supply air is cooled by conductive heat transfer between the tubes and surrounding soil. Therefore, earth ducts will not perform well as a source of cooling unless the soil temperature is lower than the desired room air temperature. Earth ducts typically require long tubes to cool the supply air to an appropriate temperature before entering the building. A fan is required to draw the air from the earth duct into the building. Some of the factors that affect the performance of an earth duct are: duct length, number of bends, thickness of duct wall, depth of duct, diameter of the duct, and air velocity.

In conventional buildings

Further information: Green building

There are "smart-roof coatings" and "smart windows" for cooling that switches to warming during cold temperatures. The whitest paint formulation can reflect up to 98.1% of sunlight.