The reader of these pages will observe that I have said nothing about a particular sort of crime which once covered Europe with human blood and raised those sorry pyres whose flames were fed with the bodies of living men. These were times when the blind mob enjoyed the pleasing spectacle and sweet harmony of hearing muffled and chaotic groans issuing from swirling black smoke – smoke of human limbs, together with the cracking of charring bones and the frying of still-quivering organs. But reasonable men will see that neither the place, the time nor the present subject-matter allow me to discuss the nature of such a crime. It would take too long, and would take me too far from my topic to show, the example of many countries notwithstanding, how necessary perfect uniformity of thought ought to be in a state; how opinions, which differ only on a few very subtle and obscure points no human intelligence can grasp, can nevertheless overthrow the public good if one view is not preferred by authority to another; and how the nature of opinion is such that, whilst some opinions are clarified by being bandied and debated so that the true rise to the top and the false sink into oblivion, others, being insecure for all the steadfastness with which they are held, need to be arrayed in authority and power.