Thirdly, That in these I call MORAL RELATIONS, I have a true notion of relation, by comparing the action with the rule, whether the rule be true or false. For if I measure anything by a yard, I know whether the thing I measure be longer or shorter than that supposed yard, though perhaps the yard I measure by be not exactly the standard: which indeed is another inquiry. For though the rule be erroneous, and I mistaken in it; yet the agreement or disagreement observable in that which I compare with, makes me perceive the relation. Though, measuring by a wrong rule, I shall thereby be brought to judge amiss of its moral rectitude; because I have tried it by that which is not the true rule: yet I am not mistaken in the relation which that action bears to that rule I compare it to, which is agreement or disagreement. CHAPTER XXIX. OF CLEAR AND OBSCURE, DISTINCT AND CONFUSED IDEAS. 1. Ideas, some clear and distinct, others obscure and confused. Having shown the original of our ideas, and taken a view of their several sorts; considered the difference between the simple and the complex; and observed how the complex ones are divided into those of modes, substances, and relations—all which, I think, is necessary to be done by any one who would acquaint himself thoroughly with the progress of the mind, in its apprehension and knowledge of things—it will, perhaps, be thought I have dwelt long enough upon the examination of IDEAS. I must, nevertheless, crave leave to offer some few other considerations concerning them. The first is, that some are CLEAR and others OBSCURE; some DISTINCT and others CONFUSED. 2. Clear and obscure explained by Sight. The perception of the mind being most aptly explained by words relating to the sight, we shall best understand what is meant by CLEAR and OBSCURE in our ideas, by reflecting on what we call clear and obscure in the objects of sight. Light being that which discovers to us visible objects, we give the name of OBSCURE to that which is not placed in a light sufficient to discover minutely to us the figure and colours which are observable in it, and which, in a better light, would be discernible. In like manner, our simple ideas are CLEAR, when they are such as the objects themselves from whence they were taken did or might, in a well-ordered sensation or perception, present them. Whilst the memory retains them thus, and can produce them to the mind whenever it has occasion to consider them, they are clear ideas. So far as they either want anything of the original exactness, or have lost any of their first freshness, and are, as it were, faded or tarnished by time, so far are they obscure. Complex ideas, as they are made up of simple ones, so they are clear, when the ideas that go to their composition are clear, and the number and order of those simple ideas that are the ingredients of any complex one is determinate and certain. 3. Causes of Obscurity.