Alfred Adler (; German: [ˈaːdlɐ]; 7 February 1870 – 28 May 1937) was an Austrian medical doctor, psychotherapist, and founder of the school of individual psychology. His emphasis on the importance of feelings of inferiority, the inferiority complex, is recognized as an isolating element which plays a key role in personality development. Alfred Adler considered a human being as an individual whole, therefore he called his psychology "Individual Psychology" (Orgler 1976).
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Theories of a wholly good or wholly malevolent world strike him as foolish. Of those who believe in a wholly good world he says that they do not understand depravity. As for pessimists, the question he asks of them is, "Is that all they see, such people?" For him, the world is both, and therefore it is neither. Merely to make a judgment of that kind is, to representatives of either position, a satisfaction. Whereas, to him, judgment is second to wonder, to speculation on men, drugged and clear, jealous, ambitious, good, tempted, curious, each in his own time and with his customs and motives, and bearing the imprint of strangeness in the world. In a sense, everything is good because it exists. Or, good or not good, it exists, it is ineffable, and, for that reason, marvelous.