finding yourself through solitary work and concentration

• Thinking means concentrating on one thing long enough to develop an idea about it. Not learning other people’s ideas, or memorizing a body of information. Developing your own ideas, thinking for yourself.

• I find for myself that my first thought is never my best thought. My first thought is always someone else’s; it’s always what I’ve already heard about the subject, always the conventional wisdom. It’s only by concentrating, sticking to the question, being patient, letting all the parts of my mind come into play, that I arrive at an original idea. By giving my brain a chance to make associations, draw connections, take me by surprise. And often even that idea doesn’t turn out to be very good. I need time to think about it, too, to make mistakes and recognise them, to make false starts and correct them, to outlast my impulses, to defeat my desire to declare the job done and move on to the next thing.
  

• solitude doesn’t always have to mean introspection. Concentrating, focusing. You can just as easily consider this lecture to be about concentration as about solitude.

  No, I don’t like work. I had rather laze about and think of all the fine things that can be done. I don’t like work—no man does—but I like what is in the work,—the chance to find yourself. Your own reality—for yourself, not for others—what no other man can ever know.

• Marlow (Heart of Darkness) believes in the need to find yourself just as much as anyone does, and the way to do it, he says, is work, solitary work. Concentration.
  

• “Your own reality—for yourself, not for others.” Thinking for yourself means finding yourself, finding your own reality.

• discovering what you believe by articulating it to a friend

linked mentions for "finding yourself through solitary work and concentration":

1. Solitude and Leadership 
   If you want others to follow, learn to be alone with your thoughts