He who devotes sixteen hours a day to hard study may become at sixty as wise as he thought himself at twenty.
Sentiment: NEGATIVE
A man who views the world the same at fifty as he did at twenty has wasted thirty years of his life.
At sixty, I know little more about wisdom than I did at thirty, but I know a great deal more about folly.
When he was twenty-three or twenty-four my father began to learn German and read philosophy in his spare hours, which did not look as though he were destined to remain long on board ship!
What's a man's age? He must hurry more, that's all; Cram in a day, what his youth took a year to hold.
The only time you really live fully is from thirty to sixty. The young are slaves to dreams; the old servants of regrets. Only the middle-aged have all their five senses in the keeping of their wits.
It is self-evident that at sixty-five a man has done all that he is fit to do.
Ripen your mind to the glorious history of the ages and revel in your mastery as today's youth shall look upon you as a sage.
The teacher's life should have three periods, study until twenty-five, investigation until forty, profession until sixty, at which age I would have him retired on a double allowance.
No matter how long he lives, no man ever becomes as wise as the average woman of forty-eight.
Be wise with speed; a fool at forty is a fool indeed.