Schopenhauer was very clear: ‘Reading is a mere surrogate for one’s own thinking.'

Two main problems concerned him:

• Opportunity cost. When you're reading, you could be thinking for yourself. This is only a problem if the kind of thinking you do while reading is significantly different from the kind you do when you are not reading. 
• Originality. Reading inserts foreign thoughts into our own, which never really belong to us.

Apart from originality, authenticity and ownership are the primary intellectual virtues that come from thinking for yourself

Thinking for yourself enables a special kind of spontaneity, variety and responsiveness to your surroundings.  Thinking for yourself does not force one specific thought on the mind, like reading. Reading has already been organised according to the mind of the author, whereas our own experiences demand that we impose some order on it ourselves.

The ultimate result of thinking for yourself is what Schopenhauer calls ‘the maturity of knowledge’, which is a state of total organic integration between thoughts and experiences. This maturity does not have to do with the power of one's intellect but the organisation of its contents. 

Thinking is, at the least, looking at things for yourself. It avoids putting a foreign concept between the mind and the world, otherwise the two will not make contact. Schopenhauer ensured that anything he found in books was assimilated only if he could connect it to experience.

Schopenhauer was never totally against reading. Seeing the world from someone else's perspective brings our attention to things we simply wouldn't have noticed. 

Schopenhauer’s real point is that reading is best when it is accompanied by thinking for yourself. It's better to read a little and read it well than to read a lot but do it poorly. When you do read, you don't have to agree with the writers.

Schopenhauer admits that reading is a better way of engaging with another person's mind because the writer's works may be richer in content than his company, the result and fruit of all his thinking and studying. 

• When Schopenhauer quotes from the authors he read, it is because he takes courage from them, but not content.
• He stresses that this still does not mean we can import literary qualities into our own writing simply by reading them.  Reading shapes us for writing by teaching us the use we can make of our own natural gifts.

Use the limits of reading by starting from where your writers left off. 

Allow your favourite authors to inspire you to look at the world differently.

Thinking for yourself does not mean you keep it all in your head.   Your original thoughts demand to be put in an external form.

It could take the form of writing, a conversation, or even in forms of expression such as visual or musical arts.