This text is partly pure thought stream; I wanted to write down what I was thinking, without self-criticism, so I can return to it later on and take it under critical study. As a result, the sentences written in bold are the thoughts themselves and the following text is where I got with them, when digging deeper into them.
Thoughts and the processed results:
Memorizing is like mental masturbation: a mere substitute for what is really sought after - understanding.
Thus: learning by memorizing is most prone to the damaging effects of aging. A person, who learns by striving toward understanding is more likely to retain a bright mind at old age than a person whose learning is based on memorizing by heart.
Note: of course you have to aqcuire knowledge by reading or going to classes or doing things in order to gain understanding; it doesn't just come to you on its own accord. What I'm saying above simply differentiates people who consciously strive to see between and beyond the lines read in a book, instead of just trying to remember.
When the limits of understanding are passed, knowledge is resorted to: knowledge can be used as a defense.
Thus, people who strive to impress others with their intelligence are simply trying to hide the limitations of their ability to comprehend (or, their bad self-esteem in general). Another such group are people who try to elevate themselves above others with book knowledge. They will recite (famous) quotes to you and they will refer to this and that book and they will keep on talking for hours on end. Just so you wouldn't get the chance to interrupt and actually ask something.
Note: knowledge in itself has little if anything to do with intelligence. Even retarded people can learn to quote famous poets or, tell you about Jungian philosophy - it just takes a lot more time for them to memorize and absorb the facts.
Understanding is a tool with which knowledge is turned into wisdom.
Thus, knowledge is the raw material without which there can be no wisdom. In order for knowledge to become wisdom one must have understanding (=experience) to process the knowledge with.
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After a lengthy discussion about my ideas I've come to refine that idea somewhat. Understanding is not a tool as such; you can not choose not to use it, nor can you choose to use some other tool. Understanding is a by-product, an emergent of intelligence and acquired knowledge. Call it experience. Thus, increasing your knowledge is likely to deepen your understanding, provided you consciously strive to understand instead of just memorizing. Then again, as there is this devious little bugger called the subconscious, which works all the time (especially while you sleep) processing the knowledge you possess and comparing situations with (and based on) what and how you have experienced earlier, it is practically impossible to avoid moments of realization.
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At this point, intelligence plays a crucial part; a more intelligent person is able to learn to remember in less time than those less intelligent. It is worth noting, however, that intelligence does not guarantee results, it simply tells the rate at which one can (permanently) obtain and absorb information for processing. Let's call it the mental bandwidth; a faster connection doesn't guarantee that the data transmitted is coherent, or that there will be any sensible end results.
As one of my older metaphors says: From books people learn to remember, from mistakes to understand. The older I've grown and the more I've gotten to know, the firmer I stand behind this. Even Einstein said "Trial and error is not the best way to learn - it is the only way". My metaphor is in fact just another way of saying the same.
Since each person is a unique individual also everyone's experiences (of similar events!) are different. Thus, everyone has a unique comprehension of what happens around them; every man's road to wisdom is different.
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Naturally, there is no such position or state as "wisdom"; stating "I am wise" in any of its forms is just a sure sign of stupidity, arrogance or over-inflated ego.
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This leads to that the only way for two persons to be exactly similar would be possible only if the knowledge and experiences they possess are perfectly identical, which is impossible. Initial situations may be the same, as may the end results but, the process in between is different for everyone. This also means that, since everyone is different and everyone processes the knowledge differently, there is also many kinds of wisdom. Everyone has similar tools - for some those tools are just better than for others - everyone still handles those tools uniquely. Thus, knowledge does not guarantee wisdom, if you don't know how to process what you have.
Hence, the breadth of one's knowledge or the rate at which the information is absorbed do not guarantee good end results - or that one ever even gets anywhere - nor do they tell anything about how well one uses his/her tools. One with less raw material can get much further than one with lots of it, if only (s)he knows what (s)he is doing - in the end, the winners are not the strongest or the most intelligent ones, but those who are most committed to victory.