(All translated into English: Attention, The Diseases of Memory, The Diseases of the Will, The Diseases of Personality, General Ideas, The Creative Imagination). Also, the works of Fouillée, which are related to German voluntarism, but contain at the same time a great deal of metaphysics and are somewhat influenced by the Platonic doctrine of ideas (L'evolutionisme des idées-forces, 1890, and Psychologie des idées-forces, 1893).
Works on the history of psychology especially worthy of mention: Siebeck, Geschichte der Psychologie, Pt. 1st, 1880–1884, and also articles in the first three vols. of Arch. f. Gesch. d. Phil, (these cover the ancient and medieval periods). Lange, History of Materialism. Dessoir, Geschichte der neueren deutschen Psychologie, 2nd ed. 1902 (including as yet only 1st vol.). Sommer, Grundzüge einer Geschichte der deutschen Psychologie und Aesthetik von Wolf-Baumgarten bis Kant-Schiller, 1892. Ribot, (English trans. by Baldwin) German Psychology of Today, Fr. ed. 1885, Eng. ed. 1886. W. Wundt, "Psychologie" in the Festschrift for Kuno Fischer, 1904.
§ 3. METHODS OF PSYCHOLOGY.
I. Since psychology has for its object, not specific contents of experience, but general experience in its immediate character, it can make use of no methods except such as the empirical sciences in general employ for the determination, analysis, and causal interpretation of facts. The fact that natural science abstracts from the subject, while psychology does not, can be no ground for modifications in the essential character of the methods employed in the two fields, though this fact does modify the way in which the methods are applied.
The natural sciences may serve, because they matured earlier, as an example for psychology in the matter of method. These sciences make use of two chief methods, namely experiment and observation. Experiment is observation under the condition of purposive control by the observer of the rise and course of the phenomena observed. Observation, in the narrower sense of the term, is the investigation of phenomena
