goats and sheep
One remark more about your reading. I do not know whether it has been sufficiently brought home to you that there are two kinds of books. When a man is reading on any kind of subject, in most departments of books – in all books, if you take it in a wide sense – you will find that there is a division of good books and bad books – there is a good kind of a book and a bad kind of a book. I am not to assume that you are all ill acquainted with this; but I may remind you that it is a very important consideration at present. It casts aside altogether the idea that people have that if they are reading any book – that if an ignorant man is reading any book, he is doing rather better than nothing at all. I entirely call that in question. I even venture to deny it. It would be much safer and better would he have no concern with books at all than with some of them. You know these are my views. There are a number, an increasing number, of books that are decidedly to him not useful. But he will learn also that a certain number of books were written by a supreme, noble kind of people – not a very great number – but a great number adhere more or less to that side of things. In short, as I have written it down somewhere else, I conceive that books are like men’s souls – divided into sheep and goats. Some of them are calculated to be of very great advantage in teaching – in forwarding the teaching of all generations. Others are going down, down, doing more and more, wilder and wilder mischief.
(On the Choice of Books)