Is this applicable to the states of mind also? Recall the shloka of the Bhagavad-Gita in which it is said that the Jiva goes out into the world, drawing round him the five senses and mind as sixth. That may throw a little light on the subject. You have five senses, the five ways of knowing, the five jnanendriyas or organs of knowing. Only by these five senses can you know the outer world. Western psychology says that nothing exists in thought that does not exist in sensation. That is not true universally; it is not true of the abstract mind, nor wholly of the concrete. But there is a great deal of truth in it. Every idea is a pentad. It is made up of five elements. Each element making up the idea comes from one of the senses, and of these there are at present five. Later on every idea will be a heptad, made up of seven elements. For the present, each has five qualities, which build up the idea. The mind unites the whole together into a single thought, synthesises the five sensations. If you think of an orange and analyse your thought of an orange, you will find in it: colour, which comes through the eye; fragrance, which comes through the nose; taste, which comes through the tongue; roughness or smoothness, which comes through the sense of touch; and you would hear musical notes made by the vibrations of the molecules, coming through the sense of hearing, were it keener. If you had a perfect sense of hearing. you would hear the sound of the orange also, for wherever there is vibration there is sound. All this, synthesised by the mind into one idea, is an orange. That is the root reason for the “association of ideas”. It is not only that a fragrance recalls the scene and the circumstances under which the fragrance was observed, but because every impression is made through all the five senses and, therefore, when one is stimulated, the others are recalled. The mind is like a prism. If you put a prism in the path of a ray of white light, it will break it up into its seven constituent rays and seven colours will appear. Put another prism in the path of these seven rays, and as they pass through the prism, the process is reversed and the seven become one white light. The mind is like the second prism. It takes in the five sensations that enter through the senses, and combines them into a single precept. As at the present stage of evolution the senses are five only, it unites the five sensations into one idea. What the white ray is to the seven- coloured light, that a thought or idea is to the fivefold sensation. That is the meaning of the much controverted Sutra: “Vrittayah panchatayych,” “the vrittis, or modes of the mind, are pentads.” If you look at it in that way, the later teachings will be more clearly understood.