We may divide thinkers into those who think for themselves and those who think through others. The latter are the rule and the former the exception. The first are original thinkers in a double sense, and egotists in the noblest meaning of the word.
Arthur SchopenhauerIn youth it is the outward aspect of things that most engages us; while in age, thought or reflection is the predominating qualityof the mind. Hence, youth is the time for poetry, and age is more inclined to philosophy. In practical affairs it is the same: a man shapes his resolutions in youth more by the impression that the outward world makes upon him; whereas, when he is old, it is thought that determines his actions.
Arthur SchopenhauerWhether we are in a pleasant or a painful state depends, finally, upon the kind of matter that pervades and engrosses our consciousness and what we compare it to - better and we envious and sad, worse and we feel grateful and happy.
Arthur Schopenhauer