Development of Modern Psychology

The De anima of Aristotle is considered the first monument of psychology as such, centered around the belief that the heart was the basis for mental activity. The foundations of modern psychology were laid by 17th-century philosopher Thomas Hobbes, who argued that scientific causes could be established for every sort of phenomenon through deductive reasoning. The mind-body theories of Rene Descartes, Baruch Spinoza, and G. W. Leibniz were equally crucial in the development of modern psychology, where the human mind's relation to the body and its actions have been significant topics of debate.

In England the empirical method employed in modern psychological study originated in the work of John Locke, George Berkeley, Thomas Reid, and David Hume. David Hartley, James Mill, John Stuart Mill, and Alexander Bain stressed the relation of physiology to psychology, an important development in the scientific techniques of modern psychology. Important contributions were made in the physiological understanding of human psychology by French philosopher Condillac, F. J. Gall, the German founder of phrenology, and French surgeon Paul Broca, who localized speech centers in the brain.

In the 19th cent., the laboratory work of Ernst Heinrich Weber, Gustave Fechner, Wilhelm Wundt, Hermann von Helmholtz, and Edward Titchener helped to establish psychology as a scientific discipline-both through the use of the scientific method of research, and in the belief that mental processes could be quantified with careful research techniques. The principle of evolution, stemming from Charles Darwin's theory of natural selection, gave rise to what became known as dynamic psychology. The new approach, presented by American psychologist William James in his Principles of Psychology (1890), looked at consciousness as an evolutionary process.