Now we talk a lot about Evolution or the _un_-folding, but we seem often not to realize that there must be something to unfold; and that therefore _In_-volution, or the concentration of the Life-principle, must be a condition precedent to its _E_-volution. This process of Involution must therefore be a process of gradually increasing concentration of the Life-principle, by association with denser and denser modes of the Universal Substance. Then, on the principle of Vibration, the less dense the substance in which the Life is immersed, the more it must be subject to being stirred by vibratory currents other than those produced by the conscious action of the Ego, or inherent Life, of the individuality that is being formed. But "_the Sum of the Vibrations in anything determines the mode, power, and direction of its action_"; therefore, the less the Ego be concentrated through association with a dense vehicle, the more "wobbly" it must be, and consequently the less able to take any effective part in the further work of Creation. But in proportion as the Ego builds up an _Individual_ _Will_, the more it gets out of the "wobbly" state--or, to refer once more to the idea of etheric waves--it becomes able to select what vibrations it will receive, and what vibrations it will send out. The involution of the Ego into the physical body, such as we at present know it, is therefore a necessity of the case, if any effective Individuality is to be brought into existence, and the work of Creation carried on instead of being cut short, not for want of material, but for want of workmen capable of using the tools of the builders' craft--the Law as "Strength" and the Word as "Beauty." The Descending Arc of the Circle of Being is therefore that of the Involution of Spirit into denser and denser modes of Substance,--a process called in technical language by the Greek name "Eleusin," and the process continues until a point is reached where Spirit and Substance are in equal balance, which is where we are now. Then comes the tug of war. Which of the two is to predominate? They are the Expansive and Constrictive primal elements, the "rouah" and "hoshech" of the Hebrew Genesis. If the Constrictive element be allowed to go further than giving necessary form to the Expansive element, it imprisons the latter. The condensation becomes too dense for the Ego to receive or send forth vibrations according to its free will, and so the Individuality becomes lost. If the condensation process be not carried far enough, no Individuality can be built up, and if it be carried too far, no Individuality can emerge; so in both cases we get the same result that there is no one to speak the Word of Power without which "Nature unaided fails."