‘The defect in naturals seems to proceed from want of quickness, activity, and motion in the intellectual faculties, whereby they are deprived of reason: whereas madmen, on the other side, seem to suffer by the other extreme. For they do not appear to me to have lost the faculty of reasoning; but having joined together some ideas very wrongly, they mistake them for truths; and they err as men do that argue right from wrong principles: for, by the violence of their imaginations, having taken their fancies for realities, they make right deductions from them. Thus you shall find a distracted man, fancying himself a king, with a right inference require suitable attendance, respect, and obedience: others, who have thought themselves made of glass, have used the caution necessary to preserve such brittle bodies. Hence it comes to pass, that a man who is very sober, and of a right understanding in all other things, may in one particular be as frantic as any in Bedlam, if either by any sudden very strong impression, or long fixing his fancy upon one sort of thoughts, incoherent ideas have been cemented together so powerfully as to remain united. But there are degrees of madness, as of folly; the disorderly jumbling together of ideas is in some more, and some less. In short, herein seems to lie the difference between idiots and madmen: that madmen put wrong ideas together, and so make wrong propositions, but argue and reason right from them: but idiots make very few or no propositions, and reason scarce at all.’ Mr. Locke’s account of Liberty and Necessity, contained in his chapter ‘On Power,’ has been commented upon in the previous Essay. As is there remarked, it is one which has been more found fault with than any other part of his work, I think without reason. He seems evidently to have admitted the definition of necessity, but not the name, which is not much to be wondered at, considering the improper use to which it is liable, and which can scarce be separated from it in the closest reasoning, much less as a term of general signification: in other words, he denies the power of the mind to act without a cause or motive, or, in any manner, in any circumstances, from mere indifference and absolute self motion; but he at the same time denies the inference which has been drawn from this principle, that the mind is not an agent at all, but altogether subject to external force, or blind impulse. Mr. Locke, in treating of complex ideas, divides them into three sorts, those of modes, substances, and relations.