With these three fundamental propositions as postulates, it will be the end and aim of this Course of Reading to develop plain, simple and specific methods and directions for the most efficient use of the mind in the attainment of practical ends. _To comprehend these mental methods and to make use of them in business affairs you must thoroughly understand the two fundamental processes of the mind._ These two fundamental processes are the Sense-Perceptive Process and the Judicial Process. The Sense-Perceptive Process is the process by which knowledge is acquired through the senses. Knowledge is the result of experience and all human experience is made up of sense-perceptions. [Sidenote: _Experience and Abstractions_] The Judicial Process is the reasoning and reflective process. It is the purely "intellectual" type of mental operation. It deals wholly in abstractions. Abstractions are constructed out of past experiences. Consequently, the Sense-Perceptive Process furnishes the raw material, sense-perceptions or experience, for the machinery of the Judicial Process to work with. [Sidenote: _Primary Mental Operations_] In this book we shall give you a clear idea of the Sense-Perceptive Process and show you some of the ways in which an understanding of this process will be useful to you in everyday affairs. The succeeding book will explain the Judicial Process. CHAPTER II SENSATIONS AND OUR PERCEPTION OF THEM [Sidenote: _Mind's Source of Supplies_] Whatever you know or think you know, of the external world comes to you through some one of your five primary senses, sight, hearing, touch, taste and smell, or some one of the secondary senses, such as the muscular sense and the sense of heat and cold. The impressions you receive in this way may be true or they may be false. They may constitute absolute knowledge or they may be merely mistaken impressions. Yet, such as they are, they constitute all the information you have or can have concerning the world about you. [Sidenote: _Does Matter Exist?_] Philosophers have been wrangling for some thousands of years as to whether we have any real and absolute knowledge, as to whether matter actually does or does not exist, as to the reliability or unreliability of the impressions we receive through the senses. But there is one thing that all scientific men are agreed upon, and that is that such knowledge as we do possess comes to us by way of perception through the organs of sense. If you have never given much thought to this subject, you have naturally assumed that you have direct knowledge of all the material things that you _seem_ to perceive about you. It has never occurred to you that there are intervening physical agencies that you ought to take into account. [Sidenote: _First-Hand Knowledge_]