Reading is merely a surrogate for thinking for yourself; it means letting someone else direct your thoughts. Many books, moreover, serve merely to show how many ways there are of being wrong, and how far astray you yourself would go if you followed their guidance. You should read only when your own thoughts dry up, which will of course happen frequently enough even to the best heads; but to banish your own thoughts so as to take up a book is a sin against the holy ghost; it is like deserting untrammeled nature to look at a herbarium or engravings of landscapes.
The art of reading is a very important one. It consists in not taking an interest in whatever may be engaging the attention of the general public at any particular time. When some political or ecclesiastical pamphlet, or novel, or poem is making a great commotion, you should remember that he who writes for fools always finds a large public. A precondition for reading good books is not reading bad ones: for life is short.
Just as one spoils the stomach by overfeeding and thereby impairs the whole body, so can one overload and choke the mind by giving it too much nourishment. For the more one reads the fewer are the traces left of what one has read; the mind is like a tablet that has been written over and over. Hence it is impossible to reflect; and it is only by reflection that one can assimilate what one has read. If one reads straight ahead without pondering over it later, what has been read does not take root, but is for the most part lost.