Meaning of “One can never read too little of bad,…”

On Liberty, Chapter 2; Mill argues for open discussion because opposing views expose weaknesses and sharpen understanding.

Analects 2:15 in James Legge’s translation; the saying balances study with independent reflection.

Of Studies, in Bacon’s instructions for how different kinds of books should be read.

The Vanity of Human Wishes (1749), first-edition scholar passage, Wikisource scan leaf 28. “And pause awhile from Learning to be wise” turns from the ambitious student’s pursuit of knowledge toward Johnson’s satirical warning that learning does not by itself remove grief, danger or error. This is eighteenth-century moral-satirical poetry after Juvenal, not a modern educational rule.

The Advancement of Learning, First Book, Project Gutenberg #5500, transcribed from the 1893 Cassell & Company edition. Bacon contrasts impatience of doubt with mature suspension of judgment and then sets out two ways of contemplation before saying that beginning with certainties ends in doubts while beginning with doubts can end in certainties. It remains early-modern epistemological argument rather than a modern experimental rule for scientific method.

Aristotle, Metaphysics, Book I, Chapter I, W. D. Ross translation (1908), validated Wikisource scan leaf 21. 'All men by nature desire to know' opens the work before the discussion of sensation, memory, experience, art and knowledge. This remains ancient philosophy mediated by translation, not a modern empirical finding about cognition.