PART I. INTRODUCTORY. CHAPTER I. AIM AND SCOPE OF PSYCHOLOGY. § 1. Provisional Definition of Psychology. Psychology (from yuxý soul, and λóyos reasoned account) is commonly defined as the science that investigates and explains the phenomena of mind, or the inner world of our conscious experience. These phenomena include our feelings of joy and sorrow, love, etc., our processes of imagination and thought, our actions so far as they are ours, that is, involve our conscious impulses and volitions, our perceptions of external objects as mental acts, and so forth. Psychology or Mental Science seeks to supply a general theory or doctrine of this group of phenomena. That is to say, it aims at giving us an accurate description of the phenomena themselves in their main varieties, and a precise statement of the general laws by which we may understand and account for these phenomena.1 § 2. Relation of Psychical to Physical Phenomena. As soon as we begin to think about this class of phenomena, we find ourselves compelled to bring them into relation to the other great group of phenomena which are (in most cases at least) studied before psychical phenomena, that is to say, physical phenomena, or the qualities and actions of material objects. It must be evident that to speak of a region of mental activity at all 1 On the origin and history of the term Psychology, see Sir W. Hamilton's Lectures on Metaphysics, i. p. 130. is implicitly to mark it off from the region of physical operations. The inner world of feeling and thought stands over against the outer world of figured material bodies with their movements, sounds, etc. The first is marked off as the subjectworld, or as the domain of the conscious subject or ego; the second as the object-world, or the domain of the non-ego.1 Without at present inquiring wherein exactly the difference consists, it is enough to call attention to the radical distinction which we instantly become aware of as soon as we try to form a clear conception of a mental fact. But, in the second place, it is no less evident that the phenomena with which the psychologist deals are closely attached to those of the material world. And the medium by which this connexion is effected is the bodily organism, and more particularly certain parts of it, which stand in a peculiarly intimate relation to our mental life, viz., the Nervous System and the organs of Sense and Movement. Wherever we discover mind or mental activity, whether in ourselves, in other men, or in the lower animals, we find it closely conjoined with the functional actions of such bodily organs. § 3. Historical Development of idea of Mind. This double relation of the psychical to the physical has always been apprehended with varying degrees of distinctness since the human mind first began to think about itself. But sometimes the one side of this relation, sometimes the other, has occupied attention to the partial exclusion of the other. In the first crude ideas of mind reached by the lower races, we may discern an effort at once to set mind in antithesis to material objects by conceiving of it as something unsubstantial and intangible, e.g., breath, smoke, an attenuated material image of the body, and also to connect it with the bodily organism as the cause of its movements. At this stage of its development, however, as these ideas of breath, etc., show, the human intellect was unable to form the abstract idea of mind as something radically unlike material things. A clearer conception of mind or soul was developed in connexion with early philo. sophic thought, and under the influence of religious feelings and aspirations. The soul was now conceived of as a separate essence or substance only temporarily and accidentally connected with the body. Here, it is evident, the difference rather than the connexion between mind and body was the point specially emphasised. In opposition to this spiritualistic tendency we find a materialistic tendency to absorb mind into the body, and to regard the activities of thought and volition as identical with, or at least as directly arising out of, the physical actions or movements of the body or of certain of its organs. 1 Subject (subjective) refers to the conscious individual who knows, is affected, and so forth; object (objective) to the thing external to the mind which is known by it or which affects it. See Hamilton's Lectures on Metaphysics, i. p. 159. As just hinted, the quasi-material form which man's first idea of the soul assumed is explained in part by the fact that a clear conception of the mental as such, and in its difference from the material, was impossible to the undeveloped intelligence. A child's first ideas about the soul are necessarily derived from, or fashioned after, material things. As a further reason, it is evident that in trying to account for the phenomena of life, such as self-initiated movement and phonation, man naturally thought of the soul or vital principle under a material form. It is not, however, to be supposed that this was the only or even the main motive. Phenomena, like shadows, images in water, dreams, and lastly death, must very early have suggested the idea of something residing within the body that is fashioned like the same, and yet is unsubstantial and capable of free egress through the solid frame. The philosophico-religious idea of the soul as a separate principle or essence, only temporarily and accidentally associated with the body, which arises at a higher stage of thought, appears in the ancient philosophy of India, and in the theology of the New Testament. It also presents itself very distinctly in Greek philosophy, more especially in the writings of Plato. In modern philosophy the opposition of mind and matter has become much more distinctly apprehended. Descartes took the lead by making mind the subject of the most direct, and therefore certain knowledge, and subsequent thinkers agree in the main in approaching the problem of knowledge by a preliminary examination of the mind that knows. At the same time the opposite tendency to materialise mind has been illustrated, not only in the avowedly materialistic systems of Hobbes, Helvetius, and others, but less manifestly in the attempts of modern biology to class mental activities with the functions of the organism, and to view them as the outcome of special organs, the nerve-centres of the brain.1 § 4. Modern Psychology and Philosophy. The modern science of psychology exhibits, like this prae-scientific thought about mind, traces of each of the two tendencies: the spiritualistic and the materialistic. The first thing to note about this modern branch of inquiry is that it has separated itself, in a measure at least, from philosophy. As a positive science, it aims merely at studying observable facts or phenomena, and drawing inferences from these, according to properly scientific methods of investigation, respecting their laws. As a science of mind, 1 On the history of the terms, soul, mind and the connected conceptions, see Sir W. Hamilton, Lectures on Metaphysics, i. p. 133; Tylor, Primitive Culture, i. chap. xi.; Siebeck, Geschichte der Psychologie, especially i., Einleitung, and ii., 2er Abschnitt, res Kap (Die Lehre vom Pneuma); Volkmann, Lehrbuch der Psychologie, § 9. The parallelism between the development of the idea of mind in the race and in the individual is brought out by Höffding, Psychology, i. 485. The bearing of psychology on the metaphysical question of Mind and Body will be best taken up at the end of our study. |