The vast, wide-spread, universal cause of our mistakes is, that we do not consider our own notions. I mean consider them in themselves—fix, settle, and determine them,—we regarding them with relation to each other only. In short, we are much out in study[ing] the relations of things before we study them absolutely and in themselves. Thus we study to find out the relations of figures to one another, the relations also of number, without endeavouring rightly to understand the nature of extension and number in themselves. This we think is of no concern, of no difficulty; but if I mistake not ’tis of the last importance, (M58) I allow not of the distinction there is made ’twixt profit and pleasure. (M59) I’d never blame a man for acting upon interest. He’s a fool that acts on any other principles. The not considering these things has been of ill consequence in morality. My positive assertions are no less modest than those that are introduced with “It seems to me,” “I suppose,” &c.; since I declare, once for all, that all I write or think is entirely about things as they appear to me. It concerns no man else any further than his thoughts agree with mine. This in the Preface. (M60) Two things are apt to confound men in their reasonings one with another. 1st. Words signifying the operations of the mind are taken from sensible ideas. 2ndly. Words as used by the vulgar are taken in some latitude, their signification is confused. Hence if a man use words in a determined, settled signification, he is at a hazard either of not being understood, or of speaking improperly. All this remedyed by studying the understanding. Unity no simple idea. I have no idea meerly answering the word one. All number consists in relations(87). Entia realia et entia rationis, a foolish distinction of the Schoolemen. (M61) We have an intuitive knowledge of the existence of other things besides ourselves & order, præcedaneous(88). To the knowledge of our own existence—in that we must have ideas or else we cannot think. (M62) We move our legs ourselves. ’Tis we that will their movement. Herein I differ from Malbranch(89). (M63) Mem. Nicely to discuss Lib. 4. c. 4. Locke(90). (M64) Mem. Again and again to mention & illustrate the doctrine of the reality of things, rerum natura, &c. (M65) Wt I say is demonstration—perfect demonstration. Wherever men have fix’d & determin’d ideas annexed to their words they can hardly be mistaken. Stick but to my definition of likeness, and ’tis a demonstration yt colours are not simple ideas, all reds being like, &c. So also in other things. This to be heartily insisted on. (M66) The abstract idea of Being or Existence is never thought of by the vulgar. They never use those words standing for abstract ideas.