But we must call the attention of the student, at this point, to the fact that the word "Mind" is used in two ways by the Yogis and other occultists, and the student is directed to form a clear conception of each meaning, in order to avoid confusion, and that he may more clearly perceive the two aspects of the things which the word is intended to express. In the first place the word "Mind" is used as synonymous with _Chitta_, or Mind-substance, which is the Universal Mind Principle. From this _Chitta_, Mind-substance, or Mind, all the material of the millions of personal minds is obtained. The second meaning of the word "Mind" is that which we mean when we speak of the "mind" of anyone, thereby meaning the mental faculties of that particular person--that which distinguishes his mental personality from that of another. We have taught you that this "mind" in Man, functions on three planes, and have called the respective manifestations (1) the Instinctive Mind; (2) the Intellect; and (3) the Spiritual Mind. (_See "Fourteen Lessons in Yogi Philosophy," etc._) These three mental planes, taken together, make up the "mind" of the person, or to be more exact they, clustered around the "I" form the "soul" of the individual. The word "soul" is often used as synonymous with "spirit" but those who have followed us will distinguish the difference. The "soul" is the Ego surrounded by its mental principles, while the Spirit is the "soul of the soul"--the "I," or Real Self. The Science of _Raja Yoga_, to which this series of lessons is devoted, teaches, as its basic principle, the Control of the Mind. It holds that the first step toward Power consists in obtaining a control of one's own mind. It holds that the internal world must be conquered before the outer world is attacked. It holds that the "I" manifests itself in Will, and that that Will may be used to manipulate, guide, govern and direct the mind of its owner, as well as the physical world. It aims to clear away all mental rubbish, and encumbrances--to conduct a "mental house-cleaning," as it were, and to secure a clear, clean, healthy mind. Then it proceeds to control that mind intelligently, and with effect, saving all waste-power, and by means of concentration bringing the Mind in full harmony with the Will, that it may be brought to a focus and its power greatly increased and its efficiency fully secured. Concentration and Will-power are the means by which the Yogis obtain such wonderful results, and by which they manage and direct their vigorous, healthy minds, and master the material world, acting positively upon Energy and Matter. This control extends to all planes of the Mind and the Yogis not only control the Instinctive Mind, holding in subjection its lower qualities and making use of its other parts, but they also develop and enlarge the field of their Intellect and obtain from it wonderful results. Even the Spiritual Mind is mastered, and aided in its