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The life of man is full of endless anxiety.
The two first [curiosity and the desire to know the causes of things] make anxiety. For being assured that there be causes of all things that have arrived hitherto, or shall arrive hereafter, it is impossible for a man, who continually endeavoureth to secure himself against the evil he fears, and procure the good he desireth, not to be in a perpetual solicitude of the time to come; so that every man, especially those that are over-provident, are in an estate like to that of Prometheus. For as Prometheus (which, interpreted, is the prudent man) was bound to the hill Caucasus, a place of large prospect, where an eagle, feeding on his liver, devoured in the day as much as was repaired in the night: so that man, which looks too far before him in the care of future time, hath his heart all the day long gnawed on by fear of death, poverty, or other calamity; and has no repose, nor pause of his anxiety, but in sleep.
Hobbes, Lev XII 5