Pygmies cannot become giants physically or intellectually. But as the puny youth can by systematic exercise broaden his frame and develop his muscles into at least a semblance of the athlete, and can then through his healthier appetite _and his faster rate of repair_ maintain himself without effort at the new standard; _so can the mentally inert call forth their reserves of energy and maintain a higher standard of activity and fruitfulness_. Few men live on the plane of their highest efficiency. Few search the recesses of the well-springs of power. The lives of most of us are passed among the shallows of the mind without thought of the possibilities that lurk within the deeper pools. [Sidenote: _How the Mind Accumulates Energy_] This accumulation of potential subconscious reserve energy is a result of the evolution of man and the growing complexity of his life. No man could, if he would, respond to all the impulses to muscular action aroused in him by sense-impressions. It would be still less possible for him to respond to every impulse to muscular action awakened from the past with the remembered thought with which it is associated. Desire, interest, attention and the selective will must pick and choose among these multitudinous tendencies to action. Here, then, is another fact that has immediate bearing upon your ability to carry out any ambition you may have. Your every action is the net result of selection among a number of impulses and inhibitory forces or tendencies. [Sidenote: _The Threshold of Inhibition_] As a general thing, consciousness is made up of a number of conflicting ideas, each with its associated feeling and its impulse to action. Just what you do in any particular case depends upon what mental picture is strongest, is most vivid in consciousness, and thus able to overcome all contrary tendencies. As life becomes more and more complex, the number and variety of our sensory experiences increase correspondingly. And so it comes about, that _we have untold millions of sensory experiences, carrying with them the impulses to muscular response, none of which, on account of the multiplicity of conflicting ideas, is ever allowed to find release and actually take form in muscular activity_. [Sidenote: _Hidden Strength_] The consequence is that only an exceedingly small proportion of the mental energy that is developed within us is ever actually displayed. _The rest is somehow and somewhere locked up behind the inhibitory threshold._ It is stored away in _subconsciousness_ with the sensory experiences of the past with which it is associated. [Sidenote: _Giving a Man Scope_]