It is with full right, therefore, that modern psychologists have applied to psychology the usual strictly methodical mode of observation, which has done such excellent service in the natural sciences. In this respect Lotze has done admirable service by his 'Medicinische Psychologie,' 1852, though he was not restrained by the title of his book from prefixing to his empirical and critical inquiries a hundred and seventy pages of metaphysic, to which it is owing that medical men have not benefited by the book as they might otherwise have done. Later, the younger Fichte presented himself to physicists and medical men physiologists, but also by men who are endeavouring to restore an empirical psychology; thus, e.g., by Stumpf in his delicately conducted inquiry into the representation of surface by the sense of sight (Ueber d. psych. Ursp. d. Raumvorst., Leipz. 1873, Kap. i. Much less successful are the inquiries in the second chap. on the 'Representation of Depth"). It is, however, easy to see that the procedure here is absolutely the same as in external observation, and that this kind of 'self-observation,' if we will use the phrase, extends exactly as far as imagination, whose functions are so closely related to those of external perception. Brentano, Psych. v. empir. Standp., i., Leipz. 1874, entirely agrees with our criticism of 'self-observation' in Fortlage's fashion; he maintains, however (S. 41), that I have been led by the confusion in this department to unjustly deny internal perception,' i.e., then the 'internal sense' (comp. the previous note). We can never direct our attention immediately to the psychical facts, and, therefore, cannot observe' them either, but we may very well 'perceive' them, and this perception may then by the aid of the memory be subjected to a more careful investigation. The objects of 'internal perception' in opposition to external are, according to Brentano, the 'psychical phenomena,' and they are to be distinguished from the physical phenomena by the criterion of "intentional inexistence," i.e., of the reference to something as object (S. 127). Accordingly Brentano reckons among physical phenomena not merely the phenomena which the senses give us, but also the pictures of imagination; psychical, on the other hand, is the idea as act of ideation (S. 103 f.). He thus, indeed, gains, like Descartes (comp. the previous note), a sure distinction between the physical and the psychical, but with the danger of making a mere illusion the foundation of his whole system. The impossibility of separating the act of ideation from its content we have shown in the previous note. But how is it with the emotions? Anger, e.g., is, according to Brentano, a psychical phenomenon, because it refers to an object. But what can we perceive in anger and observe with the aid of memory? Nothing but mere sensuous symptoms, in which again the perception everywhere stands in entire analogy with ordinary external perception. The mental element in anger lies in the mode and manner, in the measure, connexion, and order of these symptoms, not in a separable process, which might be specially perceived. in his 'Anthropologie' (1856), as it were as a sort of philosophical family doctor and spiritual adviser. Although his book, through its logical weaknesses and pretentious repetition of obsolete errors, has only injured the reputation of philosophy amongst men of science, yet in other circles it has greatly contributed to bring the close connexion of psychology and physiology home to the general consciousness. Nay, in those days happened the miracle that the Epigoni of the Hegelian philosophy partly turned towards a sober, almost scientific, treatment of psychology. George wrote a good little book on the Five Senses; Schaller found himself driven by his struggle against Materialism into a thorough consideration of the physiological element. Later, each of these men published a psychology; and in both of these works the character of the epoch is unmistakable. It deserves all praise that they are fully conscious that in essentials they still stand upon the ground of speculation, although they do so no more than do also the founders of the supposed scientific psychology. We must, on the other hand, always combat pretensions which seem to assume that speculative knowledge is higher and more credible than empirical knowledge, to which it is related simply as a higher to a lower stage. May our readers not take offence at this. It belongs to the central truths of a new epoch of humanity now dawning-not that, with Comte, we should abolish speculation, but certainly that we should once for all assign it its place, that we should know what it can do for knowledge and what not. Schaller thus expresses himself as to the relation. "Natural science may boast itself as exact knowledge, if it contents itself with discovering the laws of phenomena by observing them and with formulating the quantitative relations which are directly contained in these ascertained laws. Of course every one is at liberty to content himself with this exact knowledge; but then he necessarily resigns also any answering of all the questions with which philo sophy has concerned itself from the beginning.45 Well, then, how variously philosophy has answered the questions with which it has concerned itself is familiar enough. The agreement, however, which prevails, on the other. hand, in the natural sciences, proceeds not from those sciences confining themselves to a field where everything is obvious, but from their applying a method whose doctrines, as ingeniously elaborated as they are true to Nature, have only been revealed to mankind after long efforts, and the limits of whose applicability we do not know. The core of all the numerous cautionary measures of this method lies, however, just in the neutralising of the influence of the observer's subjectivity. But it is precisely the subjective nature of the individual man to which speculation owes each of its particular forms. Here, too, we must assume that in the similar organisation of all men, and in the common development of humanity, lies an objective basis for the individual phenomena, much as in architecture or in music similar principles appear amongst different and separated peoples. Whoever now is content under the sway of this mysterious constructive impulse of humanity to build up a temple of notions which is not indeed in serious conflict with the present state of the positive sciences, but is overthrown by every methodically-gained advance, or is razed to the ground and rebuilt in another style by every later builder, may indeed pride himself on a graceful and in itself perfect work of art, but at the same time he also necessarily resigns the hope of advancing by a single step true and permanent knowledge in any department whatsoever. What now each one will choose must remain with himself. As a rule, that will seem to each most desirable which he himself is doing. To what extent now scientific method can be applied to psychology must be shown by the result. We will premise that it is not merely the borderlands of nervous 45 Schaller, Psychologie, Weimar, 1860, S. 17. VOL. III. M physiology which admit an exact treatment. However undefined we may leave the boundaries of psychology, at all events we must for the present include in it not only the facts of sentient life, but also the investigation of human action and speech, and generally of all manifestations of life, so far as an inference is possible from them to the nature and character of man. The clearest proof for this is the existence of an Animal Psychology, the materials of which can hardly be very well collected by means of the 'internal sense.' Here, where external observation shows us primarily only movements, gestures, and actions, the interpretation of which is liable to error, we may nevertheless carry out a comparatively very exact procedure, since we can easily subject the animal to experiments and put it into positions which admit of the most accurate observation of each fresh emotion and the repetition or suspension as we will of each stimulus to a psychical activity. Thus is secured that fundamental condition of all exactness; not indeed that error is absolutely avoided, but certainly that it can be rendered harmless by method. An exactly described procedure with an exactly described animal can always be repeated, by which means our interpretation, if it is due to variable bye-conditions, is at once corrected, and at all events thoroughly cleared from the influence of personal preconceptions, which have so great a share in so-called selfobservation. If now we have as yet no system of animal psychology, yet we have the beginnings of observations which in accuracy and fruitfulness lead us far beyond the standpoint of Reimarus and Scheitlin. The constant increase in the number of zoological gardens promotes these studies, and however much the free life of the animals in field and forest may differ from their condition in captivity, yet an exact observation based upon this latter condition is not less valuable for the purpose of establishing general propositions. For the problems of Materialism or Idealism the most interesting matter will * perhaps be found later, where it has as yet been sought least in the observation of the lower animals in regard to their sense-perceptions. Indeed, Moleschott has already pointed out that a vorticella with an eye possessing only a cornea must receive different pictures of objects from the spider, which possesses also lenses and corpora vitrea. Much as we missed in our criticism of this passage a clear conception of the relation of object and subject, yet this observation is certainly important; indeed, it is not improbable that here in a very much wider sense the most remarkable things will be revealed, when exact observations are completed of the sentient activities of creatures organised so differently from ourselves. The effect of the different vibrations which are revealed to us by physics must here be examined quite independently of the question whether they cause particular sense-perceptions in our organs or not. If, for example, there should be creatures which smell or taste the light (i.e., perceive it by organs similar to our organs of smell or taste), or which receive visual images through a source of warmth which is dark to us, then the doctrine of the shaping of the sensible world by the subject would receive a new support. On the other hand, should it be shown that through all the manifold forms of the animal world there are probably no sensations essentially different from ours, this would for the present be in favour of Materialism.46 * Comp. supra, vol. ii. p. 277. 46 In this branch, too, since the appearance of our first edition, some very promising beginnings of an insight have been gained. On the one side we have Bert's experiment on the sensations of light in water-fleas, which seems to prove that in these creatures precisely the same rays excite the sensation of light as in man (communicated to the French Acad. 2 Aug. 1869); on the other side the researches of Eimer and Schöbl (Arch. f. mikrosk. Anat. vii. Hft. 3, cit. Naturf. iv. No. 26) on the organs of touch in the snout of the mole and the inner ear of the mouse, where there is such an unusual abundance of apparatus of touch, that we must suppose the kind of sensation as well as the performances of what we call the sensation of touch to be specifically different. Exact experiments are still lacking, as, on the other hand, we still need the physiological and anatomical explanation for the results long known to us of the "batsense " (according to Spallanzani's |