As with most things about life, we tend towards the conservation of energy. Ergo, we probably do not cognitate at all times to the greatest level possible, simply because the nature of our existence precludes 100% functionality all the time. We live in cycles. All of our existence is cyclical and can easily be described this way, from the minutae of every moment we wax and wane in our attentiveness and ability to maintain a line of thought, to the grandiose, wherein we are able to percieve even the cycles of the cosmos.

Control is not an issue, for the perception of control is merely an illusion of being. We are what we are, and intermittently we strive to exceed our limits, just as the puppy strives to leave his cage. It is the heaping of these drives, one upon another, that propels our development forward, to become more tomorrow than we would aspire for today. But all the time, for all our efforts, we accomplish little more than a cork bobbing in a vast sea. We can only perceive what we experience, and because of this limitation, we think we have control, but given the grand scale of things, such a notion is so closed-minded it is absurd. As a whole, at least we know now that all that we know is still much less than all that we have yet to know. In this vast unknown, then, we may someday, as a race, hope to find the meaning of what we really are. That is, if we are fortunate enough to survive that long. Maybe that question will be left for the descendents of cockroaches to answer.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)