Our objection to this view resembles much some of the objections which Professor Münsterberg himself makes when speaking of the availability of the mathematical method so-called. He says: “Measuring and counting of psychological phenomena have been made repeatedly, directly as well as indirectly, and it has been proved that mathematics can be applied to psychology.... Nevertheless it would be a misuse of the word if we named these numerical descriptions an ‘application of the mathematical method.’ If an historian of literature counts the poems and dramas of authors, if he also calculates how long it took them to write their literary products, who would call his work a mathematical history of literature? Even astronomy would be no mathematical science if we counted only the stars in the sky.” If the aim of psychological explanation were as Professor Münsterberg here asserts to be reached through the explanation of physiological states only, we should say, that the physiological method were alone admissible in psychology, a principle to which our author rightly objects. Psychical states sometimes demand a physiological explanation, and we cannot understand psychology without having a certain amount of physiological knowledge. Nevertheless, the explanation of psychical states and the necessity of certain connections must be understood mainly from the psychical elements themselves. Psychical elements, i. e. feelings, as has been explained on other occasions, have acquired and constantly do acquire meaning. This meaning which appears in sensation-symbols and thought-symbols and which is different in the different forms of feeling (correspondent to different forms of nervous action), creates a new domain,—the domain of spirit,—and thus psychical states are changed into spiritual facts. Suppose for instance that a merchant receives his mail; he opens a letter containing some important news which sets at once all his nerves into irritation, makes him neglectful of all other things in order to attend with great haste to one special affair. How can we explain this instance, or any other spiritual act through a consideration of physiological conditions. Is it not the meaning alone which special sense-impressions convey that produces the extraordinary effects? The physiologist would as little be able to detect this meaning through an analysis of the sense-impressions, as an electrician would be to understand the import of a telegram when measuring the strength of the electric current in the telegraph wires. The combinations of the purely psychical states may after all not be quite unexplainable, while their physiological concomitants are in many cases insufficient to account for spiritual interconnections.