Constantine VII Porphyrogenitus: …an anonymous chronicle known as Theophanes Continuatus, stressed the glory of the founder of his dynasty. De administrando imperio, a handbook of foreign politics, is perhaps his most valuable work, a storehouse of information on Slavic and Turkic peoples about whom little else is known except through archaeology.

Saint Theophanes the Confessor ; feast day March 12) was a Byzantine monk, theologian, and chronicler, and a principal adversary of the heterodox in the Iconoclastic Controversy (concerning the destruction of sacred images). The annals he wrote are the leading source for 7th- and 8th-century

Theophanes The Greek was one of the leading late Byzantine painters of murals, icons, and miniatures who influenced the 15th-century painting style of the Novgorod school and the Moscow school. His early career was spent in Constantinople and Crimea, but after about 1370 he worked in Russia.

Nicephorus II Phocas: Early life.: …state and the 20-year-old empress, Theophano, as acting regent for the legitimate emperors, Basil and Constantine, aged six and three, respectively. These circumstances do not seem to have tempted Nicephorus.

Epiphany, (from Greek epiphaneia, “manifestation”), Christian holiday commemorating the first manifestation of Jesus Christ to the Gentiles, represented by the Magi, and the manifestation of his divinity, as it occurred at his baptism in the Jordan River and at his first miracle, at Cana in

theophany, (from Greek theophaneia, “appearance of God”), manifestation of deity in sensible form. The term has been applied generally to the appearance of the gods in the ancient Greek and Near Eastern religions but has in addition acquired a special technical usage in regard to biblical

Edward Benlowes: During the 1640s he composed Theophila, or Loves Sacrifice (printed 1652), a long poem describing, in some fine rhapsodic passages but with extravagant conceits, the progress of the soul toward mystic communion with God. Financially crippled by the English Civil Wars and litigation, he spent his declining years at Oxford,…

Théophile de Viau was a French poet and dramatist of the pre-Neoclassical period. Born into a Huguenot family of the minor nobility, Viau went to Paris, where he soon won a reputation as the leader of the freethinkers (libertins). He was briefly house dramatist to the Hôtel de Bourgogne in Paris,

Theophilus was a German monk who wrote De diversis artibus (c. 1110–40; also called Schedula diversarum artium), an exhaustive account of the techniques of almost all the known crafts of the first half of the 12th century. From his writings it can be deduced that Theophilus was of the Benedictine

biblical literature: The Gospel According to Luke: …the same patron, “most excellent” Theophilus. Theophilus may have been a Roman called by a title of high degree because he is an official or out of respect; or he may have been an exemplification of the Gentile Christian addressees of the Lucan Gospel. The account in Luke–Acts is for…

Theophilus was an Eastern Roman emperor (829–842), principal promoter of the 9th-century Byzantine renascence of learning and the last advocate of the Eastern heresy of Iconoclasm (the destruction of religious images) in a reign beset by Arab invasions. The son of the emperor Michael II, of the

Theophilus North, novel by Thornton Wilder, published in 1973. The last work published during Wilder’s lifetime, it has striking parallels to his own life experiences and may be considered a fictionalized memoir of his artistic and philosophical life. A first-person reminiscence of life among the

Saint Theophilus of Alexandria ; feast day, Egyptian Coptic Church, October 15; in the Syrian Church, October 17) was a theologian and patriarch of Alexandria, Egypt, violent opponent of non-Christian religions, severe critic of heterodox influence among Christian writers and monks, and a major

Theophilus of Antioch was a Syrian saint, the sixth bishop of Antioch, and one of the Christian Apologists of the 2nd century. Educated in the Greek tradition, Theophilus became a Christian as an adult, after extended deliberation, and by 170 was elected bishop of Antioch. His sole surviving work

Theophilus was a German monk who wrote De diversis artibus (c. 1110–40; also called Schedula diversarum artium), an exhaustive account of the techniques of almost all the known crafts of the first half of the 12th century. From his writings it can be deduced that Theophilus was of the Benedictine

name: European patterns of naming: …a god (they are called theophoric names) or attested to his virtues, abilities, skills, possessions, and so forth. The association of the meanings of the parts of the compound was sometimes only loose, as is particularly observable in German anthroponymy (see below). Examples of compound names include the Sanskrit Viṣṇuputra…

Ericales: Theophrasteae: Formerly placed as its own family (Theophrastaceae), the tribe Theophrasteae includes four genera and 90 species of mostly shrubs and small trees that are largely restricted to the New World. Samolus (15 species) is the only herbaceous genus, and it also grows in Europe…

Theophrastus was a Greek Peripatetic philosopher and pupil of Aristotle. He studied at Athens under Aristotle, and when Aristotle was forced to retire in 323, he became the head of the Lyceum, the academy in Athens founded by Aristotle. Under Theophrastus, the enrollment of pupils and auditors rose

Theophrastus was a Greek Peripatetic philosopher and pupil of Aristotle. He studied at Athens under Aristotle, and when Aristotle was forced to retire in 323, he became the head of the Lyceum, the academy in Athens founded by Aristotle. Under Theophrastus, the enrollment of pupils and auditors rose

Theophylact of Ochrid was an Eastern Orthodox archbishop of Ochrid (modern Ohrid, North Macedonia), theologian and linguistic scholar, who helped disseminate Byzantine culture among the Balkan Slavs during the early Middle Ages. Having studied in Constantinople (now Istanbul) under the Neoplatonist

Theophylact of Ochrid was an Eastern Orthodox archbishop of Ochrid (modern Ohrid, North Macedonia), theologian and linguistic scholar, who helped disseminate Byzantine culture among the Balkan Slavs during the early Middle Ages. Having studied in Constantinople (now Istanbul) under the Neoplatonist

Theophylactus Simocattes was a Byzantine historian whose chronicles of the Eastern Roman Empire provide a unique source for the Greek relations with the Slavs and Persians during the 6th and 7th centuries. Descended from a family of high-ranking civil servants in Egypt, Simocattes held the position

Sergius III: …involved the influential Tusculani count Theophylactus. Later, Sergius became a supporter of Pope Stephen VI (VII), who exhumed Formosus’ corpse, subjected it to a posthumous trial (the “Cadaver Synod”), and nullified Formosus’ pontificate and acts. The ensuing intrigue became complex and malicious, casting a shadow over the papacy: from 896…

Benedict VIII was the pope from 1012 to 1024, the first of several pontiffs from the powerful Tusculani family. The ascendancy of the Tusculani marked the fall of the rival Crescentii family of Rome, which had come to dominate the papacy in the latter half of the 10th century. Benedict’s

Theophylactus Simocattes was a Byzantine historian whose chronicles of the Eastern Roman Empire provide a unique source for the Greek relations with the Slavs and Persians during the 6th and 7th centuries. Descended from a family of high-ranking civil servants in Egypt, Simocattes held the position

theophylline, alkaloidal drug used in medicine as an antiasthmatic, coronary vasodilator, and diuretic. Theophylline is a xanthine alkaloid, a methylxanthine chemically related to caffeine and theobromine. Along with caffeine, it is an active constituent of tea (Camellia sinensis), but it is

Theopompus of Chios was a Greek historian and rhetorician whose Philippica, though lost in its original form, has survived through the work of later writers to form one element in the tradition concerning the reign of Philip II of Macedon. Theopompus was twice exiled from his native town, first as

Argenteuil: …and of which Charlemagne’s daughter Théorade may have been an early abbess. Héloïse, of the tragic Héloïse-Abelard romance, became prioress of the convent about 1118, but she was expelled in 1129, and the convent was made into a monastery. Enshrined in the monastery’s Church of Saint-Denis is the putative seamless…

theorbo, large bass lute, or archlute, used from the 16th to the 18th century for song accompaniments and for basso continuo parts. It had six to eight single strings running along the fingerboard and, alongside them, eight off-the-fingerboard bass strings, or diapasons. Both sets of strings had

theorbo: A similar, smaller instrument, the theorbo-lute, or French lute, was a modification of the regular double-strung lute, to which were added one to three off-the-fingerboard courses of bass strings. There were two pegboxes, one angled backward. Smaller and more agile than the theorbo, the theorbo-lute was the favourite of the…

Axel Hugo Teodor Theorell was a Swedish biochemist whose study of enzymes that facilitate oxidation reactions in living cells contributed to the understanding of enzyme action and led to the discovery of the ways in which nutrients are used by organisms in the presence of oxygen to produce usable

theorem, in mathematics and logic, a proposition or statement that is demonstrated. In geometry, a proposition is commonly considered as a problem (a construction to be effected) or a theorem (a statement to be proved). The statement “If two lines intersect, each pair of vertical angles is equal,”

formal logic: Natural deduction method in PC: Such a wff is a theorem of logic. It can be shown that those theorems derivable by the rules stated above—together with the definition of α ≡ β as (α ⊃ β) · (β ⊃ α)—are precisely the valid wffs of PC. A set of natural deduction rules yielding as…

Giles of Rome: …doctrine of substance in his Theoremata de esse et essentia (“Essays on Being and Essence”). A storm of opposition from other theologians forced Giles to take refuge in Bayeux, Fr. (1278–80).

Canadian literature: The Quiet Revolution: …Madeleine Gagnon (Lueur [1979; "Glimmer"]), France Théoret (Une Voix pour Odile [1978; "A Voice for Odile"]), and Yolande Villemaire (La Vie en prose [1980; “Life in Prose”]). In her utopian novel L’Euguélionne (1976; The Euguelion), Louky Bersianik (pseudonym of Lucile Durand) used the conventions of the fantastic to conjure up…

Viktor Ambartsumian: His textbook Theoretical Astrophysics (1958) went through many editions and translations. It contains examples of his unique and fruitful approaches to stubborn astronomical problems. In addition, he studied radio signals coming from outside the Milky Way Galaxy. He was led to conclude that these radio signals represent…

computational biology: Distinctions among related fields: …can also be distinguished from theoretical biology (which itself is sometimes grouped with mathematical biology), though again there are significant relationships. Theoretical biology often focuses on mathematical abstractions and speculative interpretations of biological systems that may or may not be of practical use in analysis or amenable to computational implementation.…

chemistry: Physical chemistry: …devoted to this subject is theoretical chemistry. Theoretical chemists make extensive use of computers to help them solve complicated mathematical equations. Other branches of physical chemistry include chemical thermodynamics, which deals with the relationship between heat and other forms of chemical energy, and chemical kinetics, which seeks to measure and…

cognitive science: Approaches: …on neural networks, and (3) theoretical neuroscience, which is in part an attempt to integrate aspects of the other two approaches in a neurologically realistic account of brain activity.

Niels Bohr: Bohr’s Institute for Theoretical Physics: In the spring of 1916, Bohr was offered a new professorship at the University of Copenhagen; dedicated to theoretical physics, it was the second professorship in physics there. As physics was still pursued in the cramped quarters of the Polytechnic Institute,…

Henri Pousseur: …la musique expérimentale (1970; “Theoretical Pieces I: Experimental Music”), he argued that older methods of discussing and appraising music are in some instances not valid for music that makes use of new musical aims, resources, and techniques.

chromatography: Column efficiency: …column is reported as the number of theoretical plates (plate number), N, a concept Martin borrowed from his experience with fractional distillation: where tr is the retention time measured from the instant of injection and w is the peak width obtained by drawing tangents to the sides of the Gaussian…

philosophy of biology: Molecular biology: Finally, theoretical reductionism is the view in the philosophy of science that the entities and laws posited in older scientific theories can be logically derived from newer scientific theories, which are therefore in some sense more basic.

Sir Alan Cottrell: …work culminated in the book Theoretical Structural Metallurgy (1948), which used concepts from solid-state physics and thermodynamics and became a classic in the field.

Walther Nernst: Early research: …Regel und der Thermodynamik (1893; Experimental and Theoretical Applications of Thermodynamics to Chemistry), in which he stressed the central importance of Avogadro’s law, thermodynamics, and both physics and chemistry in the treatment of chemical processes.

Christianity: Eastern Christianity: …the vision or contemplation (theōria) of God as the goal of human blessedness found a scriptural warrant in the sixth Beatitude: “Blessed are the pure in heart, for they shall see God” (Matthew 5:8). The notion of deification (theiosis) fit with the New Testament emphasis on becoming sons of…

Eubulus: …as chief commissioner of the Theoric Fund, which provided free seats at public spectacles, to exercise control over Athenian finances, since commissioners of the fund were granted power in other departments of finance. His astute supervision of state expenditure restored the economic position of Athens without increasing the burden of…

Georg von Peuerbach: Peuerbach’s best-known work, the Theoricae novae planetarum (1454; “New Theories of the Planets”), began as lectures to the Viennese “Citizens’ School” (Bürgerschule), which Regiomontanus copied in his notebook. An influential university textbook, the Theoricae novae planetarum eventually replaced the widely used, anonymous 13th-century Theorica planetarum communis (the common “Theory…

Joseph Fourier: …analytique de la chaleur (1822; The Analytical Theory of Heat). He showed how the conduction of heat in solid bodies may be analyzed in terms of infinite mathematical series now called by his name, the Fourier series. Far transcending the particular subject of heat conduction, his work stimulated research in…

Pierre-Simon, marquis de Laplace: …Théorie analytique des probabilités (Analytic Theory of Probability), first published in 1812, in which he described many of the tools he invented for mathematically predicting the probabilities that particular events will occur in nature. He applied his theory not only to the ordinary problems of chance but also to…

Victor Riqueti, marquis de Mirabeau: In his Théorie de l’impôt (1760; “Theory of Taxation”) he attacked the tax farmers (financiers who purchased from the crown the right to collect indirect taxes) and proposed that they be replaced with a system of direct taxes on land and on personal income. Although the tax…

Julius Plücker: In Theorie der algebraischen Curven (1839; “Theory of Algebraic Curves”), he presented the famous “Plücker formulas” relating the number of singularities (points at which a function is not defined or is infinite) on algebraic curves to those of their dual curves. His System der analytischen Geometrie…

Johann Heinrich Lambert: … (1760; “The Measurement of Light”); Die Theorie der Parallellinien (1766; “The Theory of Parallel Lines”), which contains results later included in non-Euclidean geometry; and Pyrometrie (1779; “The Measurement of Heat”). The Neues Organon (1764; “New Organon”), his principal philosophical work, contains an analysis of a great variety of questions, among…

Sophus Lie: …collaboration with Engel, Lie published Theorie der Transformationsgruppen, 3 vol. (1888–93; “Theory of Transformation Groups”), which contains his investigations of the general theory of continuous groups. In 1886 Lie succeeded Klein as professor of geometry at Leipzig, where Engel had moved in 1885. Over the next 12 years Lie attracted…

Étienne-Louis Boullée: In his famous essay La Théorie des corps, Boullée investigated the properties of geometric forms and their effect on the senses, attributing “innate” symbolic qualities to the cube, pyramid, cylinder, and sphere, the last regarded as an ideal form. In a series of projects for public monuments, culminating in…

Jürgen Habermas: Philosophy and social theory of Jürgen Habermas: …Theorie des kommunikativen Handelns (1981; The Theory of Communicative Action). Drawing on the work of analytic (Anglo-American) philosophers (e.g., Ludwig Wittgenstein and J.L. Austin), Continental philosophers (Horkheimer, Adorno, Edmund Husserl, Hans-Georg Gadamer, Alfred Schutz, and György

Adrien-Marie Legendre: …systematic form under the title Théorie des nombres, 2 vol. (1830). This work included his flawed proof of the law of quadratic reciprocity. The law was regarded by Gauss, the greatest mathematician of the day, as the most important general result in number theory since the work of Pierre de…

Stefan Banach: Of his published works, his Théorie des opérations linéaires (1932; “Theory of Linear Operations”) is the most important. Banach and his coworkers summarized the previously developed concepts and theorems of functional analysis and integrated them into a comprehensive system. Banach himself introduced the concept of normed linear spaces, which are…

aesthetics: Marxist aesthetics: …Die Theorie des Romans (1920; The Theory of the Novel). Neither Lukács nor Benjamin produced a coherent aesthetics as defined in this article, although each was immensely influential on the practice of modern literary criticism whether Marxist or not in its ultimate inspiration.

Augustin Pyrame de Candolle: …published his most important work, Théorie élémentaire de la botanique, in which he contended that plant anatomy, not physiology, must be the sole basis of classification, for which he coined the term taxonomy. After introducing the concept of homologous parts (of common ancestry, although different in structure) for plants as…

anthropology: The anthropological study of religion: anthropologist Edward Evans-Pritchard (Theories of Primitive Religion [1965]), “how religious beliefs and practices affect in any society the minds, the feelings, the lives, and the interrelations of its members…religion is what religion does.” Although Edward Burnett Tylor’s classic Primitive Culture (1871) documented the wide-ranging doings of his fellow…

lü pipes: …first to develop a comprehensive music theory, and the lü pipes embody their ideas. According to legend, Huangdi, the Yellow Emperor, sent the minister Ling Lun to find bamboo tubes to use for tuning pipes. Ling Lun cut one to an auspicious length and called it the huangzhong (“yellow bell”),…

Sir William Hodge: …Hodge formulated in his book Theory and Application of Harmonic Integrals what became known as the Hodge conjecture: that for certain “nice” spaces (projective algebraic varieties), their complicated shapes can be covered (approximated) by a collection of simpler geometric pieces called algebraic cycles. The conjecture received little attention before he…

Henry Schultz: His The Theory and Measurement of Demand (1938), a survey of statistical methods and their applications, combined economic theory, particularly the mathematical work of Léon Walras and Vilfredo Pareto, with econometrics.

John Lindley: His Theory and Practice of Horticulture (1842) is considered to be one of the best books ever written on the physiological principles of horticulture. He developed his own natural system of plant classification for his best-known book, The Vegetable Kingdom (1846). Although his system was never…

David Ames Wells: …Changes (1889), and the posthumous Theory and Practice of Taxation (1900). The last two demonstrate his ability as an empirical investigator. Wells was also one of the highest-paid economists of his era. He earned $10,000 annually (20 times the average annual family income of the time) as a member of…

Joseph-Louis Lagrange, comte de l’Empire: …des fonctions analytiques (1797; “Theory of Analytic Functions”) and Leçons sur le calcul des fonctions (1804; “Lessons on the Calculus of Functions”) and were the first textbooks on real analytic functions. In them Lagrange tried to substitute an algebraic foundation for the existing and problematic analytic foundation of calculus—although…

Thorstein Veblen: Early life: In 1904 he published The Theory of Business Enterprise, in which he expanded on his evolutionary theme of the incompatibility between the modern industrial process and the irrational means of business and finance (i.e., on the difference between making goods and making money).

Jürgen Habermas: Philosophy and social theory of Jürgen Habermas: …Theorie des kommunikativen Handelns (1981; The Theory of Communicative Action). Drawing on the work of analytic (Anglo-American) philosophers (e.g., Ludwig Wittgenstein and J.L. Austin), Continental philosophers (Horkheimer, Adorno, Edmund Husserl, Hans-Georg Gadamer, Alfred Schutz, and György

Julian Steward: …theoretical work was anthologized in Theory of Culture Change: The Methodology of Multilinear Evolution (1955), in which he attempted to show that social systems arise out of patterns of resource exploitation which, in turn, are determined by the technological adaptation of a people to their natural environment. Although there are…

Eddie Redmayne: Red and The Theory of Everything: …legendary physicist Stephen Hawking in The Theory of Everything (2014).

Edward Charles Titchmarsh: …complex variable theory, he wrote The Theory of Functions (1932), which became a leading textbook on real and complex function theory and was translated into numerous languages.

Oskar Morgenstern: …John von Neumann he wrote Theory of Games and Economic Behavior (1944), applying Neumann’s theory of games of strategy (published 1928) to competitive business. Among his other books are On the Accuracy of Economic Observations (1950), Prolegomena to a Theory of Organization (1951), and Predictability of Stock Market Prices (1970;…

David Blackwell: …many publications included the classic Theory of Games and Statistical Decisions (1954; with M.A. Girshick) and Basic Statistics (1969). Blackwell was elected (1976) an honorary fellow of the Royal Statistical Society and won the John von Neumann Theory Prize in 1979.

James Edward Meade: …early important work resulted in The Theory of International Economic Policy, which was published in two volumes—The Balance of Payments (1951) and Trade and Welfare (1955). In the first of these books he sought to synthesize Keynesian and neoclassical elements in a model designed to show the effects of various…

international relations: Structures, institutions, and levels of analysis: …the publication of Kenneth Waltz’s Theory of International Politics in 1979. Neorealism represented an effort to inject greater precision, or conceptual rigour, into realist theory. While retaining power as a central explanatory notion, Waltz’s neorealism also incorporated the idea of structure as it is reflected in alliances and other cooperative…

Gottfried von Haberler: …trade, and his major work, The Theory of International Trade (1937), is considered a classic. Particularly influential was his reformulation of the theory of comparative costs in terms of opportunity cost. He introduced the production substitution curve (now referred to as the production-possibility frontier), which offered a framework for considering…

democracy: Rawls: In A Theory of Justice (1971), the American philosopher John Rawls attempted to develop a nonutilitarian justification of a democratic political order characterized by fairness, equality, and individual rights. Reviving the notion of a social contract, which had been dormant since the 18th century, he imagined…

Rudolf Stammler: …translated by Isaac Husik as The Theory of Justice (1925).

Edward Hastings Chamberlin: …thesis became the basis for Theory of Monopolistic Competition (1933), a book that spurred discussion of competition, especially between firms whose consumers have preferences for particular products and firms that control the prices of their products without being monopolists.

Adam Smith: The Theory of Moral Sentiments of Adam Smith: In 1759 Smith published his first work, The Theory of Moral Sentiments. Didactic, exhortative, and analytic by turns, it lays the psychological foundation on which The Wealth of Nations was later to be built. In it Smith described…

Lev Semyonovich Pontryagin: …led to his fundamental monograph, Theory of Optimal Processes (1961; English translation 1962). In later years he wrote several other expository works on mathematics.

political science: Theory of rational choice: In The Theory of Political Coalitions (1962), Riker demonstrated by mathematical reasoning why and how politicians form alliances. Riker and his followers applied this version of rational choice theory—which they variously called rational choice, public choice, social choice, formal modeling, or positive political theory—to explain almost…

William Stanley Jevons: …logician and economist whose book The Theory of Political Economy (1871) expounded the “final” (marginal) utility theory of value. Jevons’s work, along with similar discoveries made by Karl Menger in Vienna (1871) and by Léon Walras in Switzerland (1874), marked the opening of a new period in the history of…

metalogic: Satisfaction of a theory by a structure: finite and infinite models: …to the book Wissenschaftslehre (1837; Theory of Science) by Bernhard Bolzano, a Bohemian theologian and mathematician, and, in a more concrete context, to the introduction of models of non-Euclidean geometries about that time. In the mathematical treatment of logic, these concepts can be found in works of the late 19th-century…

organizational analysis: Origins of the discipline: and modernization (eventually published as Theory of Social and Economic Organization; 1947), Weber attributed the rise of organizations to the expansion of markets, to developments in the law, and especially to changes in the nature of authority.

Brooks Adams: In 1913 he published The Theory of Social Revolutions, a study of defects in the American form of government, developing the idea of the imminent danger in the existence of great wealth that exerted private power but declined to accept responsibility. After Henry Adams’ death, Adams prepared for publication…

S.F. Nadel: In his posthumous Theory of Social Structure (1958), sometimes regarded as one of the 20th century’s foremost theoretical works in the social sciences, Nadel examined social roles, which he considered to be crucial in the analysis of social structure.

Lord Rayleigh: …work on his great book, The Theory of Sound, in which he examined questions of vibrations and the resonance of elastic solids and gases. The first volume appeared in 1877, followed by a second in 1878, concentrating on acoustical propagation in material media. After some revision during his lifetime and…

John Robert Schrieffer: He published Theory of Superconductivity in 1964.

Sir William Rowan Hamilton: …first published mathematical paper, “Theory of Systems of Rays,” begins by proving that a system of light rays filling a region of space can be focused down to a single point by a suitably curved mirror if and only if those light rays are orthogonal to some series of…

consumption: The rational optimization framework: economist Milton Friedman’s treatise A Theory of the Consumption Function (1957). The permanent income hypothesis omits the detailed treatment of demographics and retirement encompassed in the life-cycle model, focusing instead on the aspects that matter most for macroeconomic analysis, such as predictions about the nature of the consumption function,…

uniformitarianism: Hutton’s contributions: …published in two volumes as Theory of the Earth (1795)—at meetings of the Royal Society of Edinburgh. Hutton showed that Earth had a long history that could be interpreted in terms of processes observed in the present. He showed, for instance, how soils were formed by the weathering of rocks…

ethics: Moral realism: In A Theory of the Good and the Right (1979), Brandt went so far as to include in his idealized conditions a requirement that the person be motivated only by “rational desires”—that is, by the desires that he would have after undergoing cognitive psychotherapy (which enables…

conspicuous consumption: …the term in his book The Theory of the Leisure Class (1899). The concept of conspicuous consumption can be illustrated by considering the motivation to drive a luxury car rather than an economy car. Any make of car provides transport to a destination, but the use of a luxury car…

location theory: …den Standort der Industrien (Theory of the Location of Industries, 1929). Weber’s theory, called the location triangle, sought the optimum location for the production of a good based on the fixed locations of the market and two raw material sources, which geographically form a triangle. He sought to determine…

aesthetics: Marxist aesthetics: …Die Theorie des Romans (1920; The Theory of the Novel). Neither Lukács nor Benjamin produced a coherent aesthetics as defined in this article, although each was immensely influential on the practice of modern literary criticism whether Marxist or not in its ultimate inspiration.

Gerard Debreu: Debreu’s classic monograph, Theory of Value: An Axiomatic Analysis of Economic Equilibrium, was published in 1959. In it Debreu provided the mathematical underpinnings for the phenomenon of equilibrium in supply and demand that was first articulated (as the “invisible hand” that leads self-seeking men unwittingly to aid society)…

George Berkeley: His American venture and ensuing years: Berkeley replied with The Theory of Vision, or Visual Language…Vindicated and Explained (1733). This fine work brought the metaphysics of the Essay into line with the Principles and added his doctrine of cause, admitting defects in the premises of the original Essay. Alciphron provoked replies from the satirist…

scientific theory, systematic ideational structure of broad scope, conceived by the human imagination, that encompasses a family of empirical (experiential) laws regarding regularities existing in objects and events, both observed and posited. A scientific theory is a structure suggested by these