Quote from : The Plague Book

The evil that is in the world comes out of ignorance, and good intentions may do as much harm as malevolence, if they lack understanding. One the whole, men are more good than bad; that, however, isn't the real point. But they are more or less ignorant, and it is this that we call vice or virtue; the most incorrigible vice being that of an ignorance that fancies it knows everything and therefore claims for itself the right to kill.