INTRODUCTORY. 7 



and inspired by Leibniz, seems to me to have impressed 

 upon many of the prominent thinkers in Germany, Eng- 

 land, and France of to-day the tone of their thought, 

 and suggested the attitude they have taken up to the 

 great philosophical problems. 



From the foregoing it might appear as if the process of 

 philosophical thought were similar to that which I have 

 had occasion to point to in many passages in the earlier 

 volumes of this work. I there showed how various 

 terms handed down from earlier as-es with a vague and 

 undefined meaning have been raised to the rank of lead- 

 ing ideas by the scientific thought of recent times. Such 

 terms were, e.g., "attraction," "repulsion," "atom," "mass " 

 and " motion," " energy," " form," " development," &c. 

 By being clearly defined — i.e., by having a fixed meaning 

 attached to them — they have become centres around 

 which the scientific thought of the century has gathered, 

 and which have guided us in that survey which this 

 History has undertaken. 



It would appeal- as if an analogous process might guide 

 us in our survey of the philosophical thought of the 



■ Therapie als mechaiiische 

 Naturwissenschaften ' (1842). 



'Logik' (1843). 



Articles — " Leben," " Lebens- 

 straft," " lustinkt," "Seele 

 und Seelenleben," in Wagner's 

 ' Handworterbuch der Physi- 

 ologie ' (1843-46). 



' Ueber den Begriff der Schon- 

 heit' (1845), and 'Ueber 

 Bedingungen der Kunstschon- 

 heit' (1847). 



• Allgemeine Physiologie des 

 Korperlichen Lebens ' (18.51). 



' Medicinische Psychologie oder 

 Physiologie der Seele' (1852). 



' Microcosmus,' 3 vols. (1856-64). 



' Streitschriften ' (1857). 



' Geschichte der Aesthetik in 

 Deutschland' (1868). 



' System der Philosophic ' (2 vols. 

 'Logik,' ' Metaphysik,' 1874- 

 79). 



The dictated Notes of his Lec- 

 tures were published after his 

 death in eight parts, and his 

 ' Kleinere Schrifteu ' have been 

 collected in four volumes and 

 edited by Peipers (1885 - 91). 

 English translations have appeared 

 of the ' Microcosmus,' the ' System,' 

 and the ' Dictate. ' 



