<P> The philosophers of the British Empiricist and Associationist schools had a profound impact on the later course of experimental psychology . John Locke's An Essay Concerning Human Understanding (1689), George Berkeley's Treatise Concerning the Principles of Human Knowledge (1710), and David Hume's A Treatise of Human Nature (1739--1740) were particularly influential, as were David Hartley's Observations on Man (1749) and John Stuart Mill's A System of Logic . (1843). Also notable was the work of some Continental Rationalist philosophers, especially Baruch Spinoza's (1632--1677) On the Improvement of the Understanding (1662) and Gottfried Wilhelm Leibniz's (1646--1716) New Essays on Human Understanding (completed 1705, published 1765). Also was an important contribution Friedrich August Rauch's (1806--1841) book Psychology: Or, A View of the Human Soul; Including Anthropology (1840), the first English exposition of Hegelian philosophy for an American audience . </P> <P> The Danish philosopher Søren Kierkegaard also influenced the humanistic, existential, and modern psychological schools with his works The Concept of Anxiety (1844) and The Sickness Unto Death (1849). </P> <P> Also influential on the emerging discipline of psychology were debates surrounding the efficacy of Mesmerism (a precursor to hypnosis) and the value of phrenology . The former was developed in the 1770s by Austrian physician Franz Mesmer (1734--1815) who claimed to use the power of gravity, and later of "animal magnetism", to cure various physical and mental ills . As Mesmer and his treatment became increasingly fashionable in both Vienna and Paris, it also began to come under the scrutiny of suspicious officials . In 1784, an investigation was commissioned in Paris by King Louis XVI which included American ambassador Benjamin Franklin, chemist Antoine Lavoisier and physician Joseph - Ignace Guillotin (later the popularizer of the guillotine). They concluded that Mesmer's method was useless . Abbé Faria, an Indo - Portuguese priest, revived public attention in animal magnetism . Unlike Mesmer, Faria claimed that the effect was' generated from within the mind' by the power of expectancy and cooperation of the patient . Although disputed, the "magnetic" tradition continued among Mesmer's students and others, resurfacing in England in the 19th century in the work of the physician John Elliotson (1791--1868), and the surgeons James Esdaile (1808--1859), and James Braid (1795--1860) (who reconceptualized it as property of the subject's mind rather than a "power" of the Mesmerist's, and relabeled it "hypnotism"). Mesmerism also continued to have a strong social (if not medical) following in England through the 19th century (see Winter, 1998). Faria's approach was significantly extended by the clinical and theoretical work of Ambroise - Auguste Liébeault and Hippolyte Bernheim of the Nancy School . Faria's theoretical position, and the subsequent experiences of those in the Nancy School made significant contributions to the later autosuggestion techniques of Émile Coué . It was adopted for the treatment of hysteria by the director of Paris's Salpêtrière Hospital, Jean - Martin Charcot (1825--1893). </P> <P> Phrenology began as "organology", a theory of brain structure developed by the German physician, Franz Joseph Gall (1758--1828). Gall argued that the brain is divided into a large number of functional "organs", each responsible for particular human mental abilities and dispositions--hope, love, spirituality, greed, language, the abilities to detect the size, form, and color of objects, etc . He argued that the larger each of these organs are, the greater the power of the corresponding mental trait . Further, he argued that one could detect the sizes of the organs in a given individual by feeling the surface of that person's skull . Gall's ultra-localizationist position with respect to the brain was soon attacked, most notably by French anatomist Pierre Flourens (1794--1867), who conducted ablation studies (on chickens) which purported to demonstrate little or no cerebral localization of function . Although Gall had been a serious (if misguided) researcher, his theory was taken by his assistant, Johann Gaspar Spurzheim (1776--1832), and developed into the profitable, popular enterprise of phrenology, which soon spawned, especially in Britain, a thriving industry of independent practitioners . In the hands of Scottish religious leader George Combe (1788--1858) (whose book The Constitution of Man was one of the best - sellers of the century), phrenology became strongly associated with political reform movements and egalitarian principles (see, e.g., Shapin, 1975; but also see van Wyhe, 2004). Phrenology soon spread to America as well, where itinerant practical phrenologists assessed the mental well - being of willing customers (see Sokal, 2001). </P>

Which of the following approaches to psychology was brought to existence most recently