upon questions which exceed the bounds of phenomena, e. g. as to the nature of mind out of relation to the living organism, he passes the limits of science and therefore of psychology, as this term is here employed. As regards the study of mind, empirical psychology, assisted by physiology, will and ought to have the first word, though it cannot have the last.

tion of

psycho

§3. The ancient Greek psychologists endeavoured to give Appreciaobservation its due weight in determining such psychological ancient questions as they raised. For this reason they deserve to be Greek called the founders of psychological science. Their honest fogy. differences from one another, as well as from their better informed successors, and their helpless ignorance of much which is now familiarly known and fundamental for psychology, contribute to the curious interest which a history of their efforts has for a modern reader. This history is, of course, largely a history of failure. Those, however, who know how far empirical psychology is still from the achievement of its aims will not hastily disparage the Greeks on this account. It was not so much the defectiveness of their psychological methods-defective as these were no doubt-as that of their physical and physiological science that rendered fruitless their best attempts to comprehend the elementary facts of sense-perception, and to place them in an intelligible connexion with their conditions. The most ancient Greek psychologists treated psychology as an integral part of physics or of physiology. With the possible exception of Anaxagoras, they looked upon 'knowing,' for example, as one of the many properties of matter. Problems as to the nature of space, critically considered, lay beyond their horizon. They never asked how it comes to pass that we 'project' our percepts in an extra-organic space, and fall into the habit of speaking of them as outside ourselves. Questions of the objective existence of things whose qualities are perceived or known only in virtue of our faculty of cognition did not come up for discussion until some centuries after Thales. Before the Sophists-or 'die Sophistik '—all agreed that there is on one hand such a thing as truth

(however difficult to discover sometimes), and, on the other, such a thing as its opposite, error or falsehood. The spirit of the Sophistic age, however, dissolved the barrier which divided Truth from Error, making a new departure necessary if philosophy and science alike were not to cease utterly among men. For want of positive knowledge and of method, science and philosophy alike were ultimately endangered in the confusion to which undisciplined speculation led the followers of Heraclitus.

As regards scientific method, it was not to be expected that it could exist at a period when logic-deductive and inductive-was as yet unknown, and when the provinces of the various departments of thinking had as yet no boundaries assigned to them. As regards positive knowledge, again, the disadvantages under which the Greek psychologists laboured were insuperable. Pure mathematics had advanced to an important degree of attainment, but empirical sciences, e.g. physics and physiology, were in their infancy. Even Aristotle, like his predecessors, with whom he so often places himself in controversy, possessed only the scantiest means of physical observation. In fact, observation did not go beyond what could be accomplished by the naked eye. Physical experiments only of the most rudimentary kind were possible at a time when, of all our varied mathematical and physical implements, inquirers had to content themselves with what they could achieve by the aid of the rule and the compasses. 'Chemical analysis, correct measurements and weights, and a thorough application of mathematics to physics were unknown. The attractive force of matter, the law of gravitation, electrical phenomena, the conditions of chemical combination, pressure of air and its effects, the nature of light, heat, combustion, &c., in short all the facts on which the physical theories of modern science are based, were wholly, or almost wholly, undiscovered 1.' In their attempts at psychology under such circumstances it is not to be wondered at if they met with but little success. They had, for example, to arrive at 1 Vide Zeller, Aristotle, i. p. 443, E. Tr.

1

a theory of vision without a settled notion of the nature of light, or of the anatomical structure of eye or brain. They had to explain the operation of hearing without accurate knowledge of the structure of the inner ear, or of the facts and laws of sound, or at least with only some few mathematical ideas gleaned from the study of harmonics. Physiology and anatomy, chemistry and physics, as yet undifferentiated, lay within the body of vague floating possibilities of knowledge studied by them under the name of Nature. For want of a microscope their examination of the parts of the sensory organs remained barren. They had no conception of the minuteness of the scale on which nature works in the accomplishment of sensory processes and in the formation of sensory organs. The retina, as well as the structure of the auditory apparatus, was wholly unknown to them. The nerve-system had not been discovered, and the notions formed of the mechanism of sensation and motion1 were hopelessly astray. The veins, with the blood or (as some thought) the air coursing through them, were looked upon as discharging the functions now attributed to the sensory and motor nerves. Even Aristotle did not know the difference between veins and arteries. When this difference was first perceived, it was for a time still supposed that the veins conducted the blood, the arteries the air. Perhaps the climax of our surprise is reached when we find Plato of opinion that not only air, but also drink, passed into the lungs 2. Yet in this opinion Plato was at one with the best, or some of the best, medical teaching of his time. As early as Alcmaeon of Crotona the brain had been thought of as the central organ of sentiency, and, in short, of mind; and Plato held that it was so. But Aristotle, again, declares this to be untrue, and holds that the heart is the great organ of perception

1 Vide Galen. de Placit. Hipp. et Plat. §§ 644 seqq.; especially Ερασίστρατος [294 Β. C.] μὲν οὖν, εἰ καὶ μὴ πρόσθεν, ἀλλ ̓ ἐπὶ γήρως γε τὴν ἀληθῆ τῶν νεύρων ἀρχὴν κατενόησεν ̓Αριστοτέλης δὲ μέχρι παντὸς ἀγνοήσας εἰκότως ἀπορεῖ χρείαν εἰπεῖν ἐγκεφάλου.

2 Timaeus 70 c.

and of mind so far as this has a bodily seat. Empedocles had supposed the blood, especially that in the region of the heart, to be the locus or habitation of mind. Thus ignorant of, and therefore free to differ about, cardinal facts and laws of anatomy, physiology, and physics, the ancient Greeks were unable to make real advances towards explaining the conditions of the most obscure of all phenomena-those of Mind.

Dialectical § 4. Under these circumstances many of the Greeks, psychology. perhaps feeling the hopelessness of such attempts at empirical psychology, occupied themselves for the most part with discursive speculations which really aimed at little more than the clearing up of common ideas or words. Thus Plato's Theaetetus is largely occupied with an endeavour to determine the meaning of tɩotýμn, or knowledge. Disquisitions on methodology, too, came to receive much attention from Plato as well as Aristotle; but the scientific experimental work itself, on which real advance depends, was lacking. Laborious efforts of genius like Plato's ended, too often, for the time in the production of categories, which, however they may have enriched philosophy, left empirical psychology no better off than it had been before. But in place of empirical there came a sort of dialectical or 'rational' psychology, studying, or professing to study, the soul and its faculties per se, apart from experience and from organic life in this physical world. With this form of psychology, whether it shows itself in Aristotle or in his predecessors, we shall here have as little as possible to do. § 5. In order that we may most conveniently illustrate the progress of psychological speculations, we shall allow the authors of these speculations to a great extent to speak for themselves through the medium of a translation. Some commentary will be, occasionally, necessary not only to explain particular dicta but to exhibit special doctrines in their due relationship to others.

Sources of our know

ledge of

ancient

Greek psychology.

Our first and greatest authorities for the history of psychology, as of so much else in philosophy and science, are of course Plato and Aristotle, especially the latter. We

shall avail ourselves also of the valuable fragment of Theophrastus de Sensu. The information derived from these writers as to the tenets of previous thinkers has always to be scanned closely in order to discover whether it is objectively true, or whether allowance has to be made for differences of standpoint, or for misrepresentation due to antagonistic attitudes. Still we are most favourably situated when we have Plato, Aristotle, and Theophrastus as our guides. Records such as are preserved in the pages of incompetent historians of philosophy or compilers of philosophic dogmas who may have lived several centuries after Christ, when the works of some of the authors with whom they deal were no longer extant or only survived in doubtful tradition, must be received with steady scepticism and tested by every means in one's power. In many cases these records contain intrinsic proof of untrustworthiness; and they are nearly always tinged with the colour of later theories which had superseded in the popular mind those promulgated by the earlier psychologists. Thus much of what is ascribed in Stobaeus or the Pseudo-Plutarch to Democritus is, from the terms in which it is couched, evidently contaminated with the teaching of Epicurus; much that is ascribed to Plato or Aristotle is expressed in the terminology of Stoicism.

§ 6. We shall commence by giving a detailed account of Method of what the writers already named in § 1 each had to say exposition. following of the particular functions, organs, &c. of seeing, hearing, smelling, tasting, touching; of the objects of these senses as such, and of the media through which the objects were supposed to operate. Next we shall present such theories as they have left on record of sensation in general, and of the faculty (referred by Plato to intelligence, by Aristotle to sense) which compares and distinguishes the data of the particular senses, and to which such activities as those of imagination and memory belong. Finally, we might be expected to discuss the connexion between the faculty of sense and that of reason. With this subject, however, we shall at present have nothing to do. To discuss it would at