Source identified1
“The art of not reading is highly important.”
Selecting what not to read protects limited attention from being consumed by material that is merely fashionable, noisy, or low-value.
Source note: Essay “On Books and Reading”; the surrounding passage explains selective reading rather than hostility to books generally.
Source identified2
“Reading is thinking with some one else's head instead of one's own.”
Reading supplies another mind’s thought, but Schopenhauer warns that consuming ideas should not replace the work of forming one’s own connected judgment.
Source note: Essay “On Books and Reading,” in a public-domain English collection of Schopenhauer’s essays.
Source identified3
“One can never read too little of bad, or too much of good books: bad books are intellectual poison; they destroy the mind.”
The deliberately severe contrast argues that reading quality matters because repeated exposure influences the habits and material of thought.
Source note: Essay “On Books and Reading,” public-domain English text.
Source identified4
“In order to read what is good one must make it a condition never to read what is bad; for life is short, and both time and strength limited.”
Finite time makes selection unavoidable, so choosing worthwhile reading also requires declining material that does not deserve limited attention.
Source note: Essay “On Books and Reading”; Schopenhauer connects literary selection directly with limited time and strength.