As much as you can gather! It will never be enough, there is so much to know.
Without knowledge it gets hard to develop a sense of appreciation, which is required if you want to be content in life. For example, you know how complex the human body is, and yet so fragile, so you learn to take care of it.
As long as you have the knowledge to appreciate and cherish all the good things in your life, you're doing pretty well.
There was this scientist who came across a river while he was traveling; the only way to get across was by a boat that was moored nearby. He approached the boatman and requested him to ferry him across.
While they were crossing the river, the scientist, by way of conversation, asked the boatman "Did you go to school? Do you have any knowledge of the world we are living in?" The boatman replied "No, sir - my father was a boatman and when he passed on, I took up the job"
The scientist told the boatman "That's a shame! You see, knowledge is everything in life. Without knowledge, half your life is lost" and so on.
Suddenly the boat sprung a leak and water started getting in; the boat was slowly sinking.
The boatman shouted at the panicking scientist "Sir, do you know how to swim?" to which the scientist yelled "NO! Please save me!"
The river was rough and the boatman could not save the scientist - so he told the scientist "What a shame! If you don't know how to swim, your entire life is lost!" and he swam across to the shore.
On the other hand, let's take SHERLOCK HOLMES the character created by Sir Arthur Conan Doyle. One of the most widely held notions about Sherlock Holmes has to do with his supposed ignorance of basic astronomy. “What the deuce is the solar system to me?” he exclaims to Dr. Watson in A Study in Scarlet. “You say that we go round the sun. If we went round the moon it would not make a penny-worth of difference to me or to my work.”
“I consider that a man’s brain is like a little empty attic, and you have to stock it with such furniture as you choose.”
Need I say anything more?
All Knowledge is Needed at some point in life.
