He is quite right in questioning the usefulness of getting involved in an endless study of the intricate classifications of his surroundings, if they are illusory. From the standpoint of the Ultimate Path such a study is a waste of time and therefore is not indulged in. The aim of this path is to know the ultimate reality--knowing which, all its illusory reflections are naturally understood. However, he must be careful in the use of the word "illusory." The world is not illusory but the apprehension of it through the senses is. Each object regarded separately as an independent entity is illusory but regarded as what it is in its formless essence it is real. To put this in plainer language: everything seen is merely an idea in the mind. Ideas come and go and in this sense only are unreal; but the stuff out of which they are formed--that is, Mind--does not come and go and constitutes the ultimate basis of all ideas and therefore of their ultimate reality. He seeks to understand what this Mind is.
He may now begin to realize that all the theosophical teachings about the seven principles of man, the five tattvas (cosmic forces), and prakriti (root matter) are teachings given to beginners who are unable to grasp the great truth that all these are merely ideas and that Mind alone is what he should seek to know. H.P. Blavatsky gave these teachings because she knew that the nineteenth-century West was not metaphysically minded but rather scientifically inclined and science in those days was horribly materialistic. What else could she do but give out these lower grade teachings? She herself writes in one of her books that she has given only three or four turns of the key in the lock of universal mystery. The time has come in the mid-twentieth century to give the remaining turns which will make known the higher philosophical truth for which mankind is now better prepared.
-- Notebooks Category 21: Mentalism > Chapter 3: The Individual and World Mind > # 3