that our simple ideas at least are innate, and in rejecting the Tabula rasa of Aristotle and of Mr. Locke.  But I cannot agree with him that our ideas have scarce any more relation to things than words uttered into the air or writings traced upon paper have to our ideas, and that the bearing of our sensations is arbitrary and ex instituto, like the signification of words.  I have already indicated elsewhere why I am not in agreement with our Cartesians on that point.

5.  For the purpose of advancing to the first Cause, the author seeks a criterion, a distinguishing mark of truth; and he finds it in the force whereby our inward assertions, when they are evident, compel the understanding to give them its consent.  It is by such a process, he says, that we credit the senses.  He points out that the distinguishing mark in the Cartesian scheme, to wit, a clear and distinct perception, has need of a new mark to indicate what is clear and distinct, and that the congruity or non-congruity of ideas (or rather of terms, as one spoke formerly) may still be deceptive, because there are congruities real and apparent.  He appears to recognize even that the inward force which constrains us to give our assent is still a matter for caution, and may come from deep-rooted prejudices.  That is why he confesses that he who should furnish another criterion would have found something very advantageous to the human race.  I have endeavoured to explain this criterion in a little Discourse on Truth and Ideas, published in 1684; and although I do not boast of having given therein a new discovery I hope that I have expounded things which were only confusedly recognized.  I distinguish between truths of fact and truths of reason.  Truths of fact can only be verified by confronting them with truths of reason, and by tracing them back to immediate perceptions within us, such as St. Augustine and M. Descartes very promptly acknowledged to be indubitable; that is to say, we cannot doubt that we think, nor indeed that we think this thing or that.  But in order to judge whether our inward notions have any reality in things, and to pass from thoughts to objects, my opinion is that it is necessary to consider whether our perceptions are firmly connected among themselves and with others that we have had, in such fashion as to manifest the rules of mathematics and other truths of [410] reason.  In this case one must regard them as real; and I think that it is the only means of distinguishing them from imaginations, dreams and visions.  Thus the truth of things outside us can be recognized only through the connexion of phenomena.  The criterion of the truths of reason, or those which spring from conceptions, is found in an exact use of the rules of logic.  As for ideas or notions, I call real all those the possibility of which is certain; and the definitions which do not mark this possibility are only nominal.  Geometricians well versed in analysis are aware what difference there is in this respect between several properties by which some line or figure might be defined.  Our gifted author has not gone so far, perhaps; one may see, however, from the account I have given of him already, and from what follows, that he is by no means lacking in profundity or reflexion.