Ever since Psychology came to be studied as a separate branch of human knowledge, its nature has been defined differently by different experts.

(a) Psychology as the Science of Soul

The word, “Psychology” is derived from two Greek words, “Psyche’ which means soul and ‘logos’ which means talk about’ or ‘study’ of. So, the term means the ‘study of soul’. But, to define Psychology as the ‘science of soul’, is to defeat the very meaning of ‘science’. The nature and origin of soul are not known and thus ‘soul’ cannot be put to any scientific study. Soul is a metaphysical concept. Its basis is theology and accepts no logic. In this sense, Psychology becomes more of a religious pursuit than a scientific one.

Modern psychology, as James says, is ‘a psychology without a soul”.

(b). Psychology as the Science of Mind

In the 18th Century, Psychology was understood as the ‘study of mind’ or the ‘study of mental processes’. But soon it was felt that the term ‘mind’ is as vague as the term ‘soul’. Hume and Titchener reject the popular conception of mind as an entity or a substance. A man in the street looks upon mind as some agent which thinks, feels, wills and does many other things. Titchener is against this view. He says that mind is itself. not has, thoughts, feelings and wills. ‘Mind’ is only a short-hand name for all the mental processes. Thus the truths about the nature of ‘Mind’ have been interpreted subjectively, from person to person. So, to say that Psychology is the ‘study of mental processes’ is incomplete or one-sided because through this we cannot know the mental processes of other individuals. So, this definition is subjective, half-truth and very personal.

c) Psychology as the Science of Consciousness

Still later, Psychology was defined as the “Science of consciousness”.

The term ‘consciousness’ means our immediate awareness of any object. It is, to put simply, ‘mind- now’. But, this definition, too, was rejected as one-sided. The scope of psychology is not only limited to the conscious level but also extends to the sub-conscious and unconscious mind. These form the major portions and exert important influence on the behaviour of a person.

(d) Psychology as the Science of Behaviour

Psychology may be defined as the scientific study of behaviour is the science of behaviour.

Psychology as the science of behaviour studies the total response of the organism to different situations of life. In this sense, psychology studies behaviour- physical as well as mental, normal as well as abnormal, child behaviour as well as adult behaviour.

Many other psychologists like Watson, Pilsbury, Skinner, Munn, Crow and Crow have defined Psychology as a positive science of behaviour.

In the light of the above, Psychology may be defined as a positive and empirical science dealing with mental life and its external expression (behaviour).

In the words of Garret:

“Psychology is the study of human behaviour and its subject-matter is what people do and how and why they do.”

McDougall has also defined Psychology as “the positive science of conduct and behaviour.

” It is the science which aims “to give us better understanding and control of the behaviour of the organism as a whole.”

The changing concept of Psychology has been aptly described

by Woodworth in these words:

“First Psychology lost it soul, then it lost its mind, then it lost consciousness, it still has behaviour of a kind.”