Fenelon disengages badly enough the process which conducts from ideas, from universal and necessary truths, to God. Bossuet renders to himself a strict account of this process, and marks it with force; it is the principle that we have invoked, that which concludes from attributes in a subject, from qualities in a being, from laws in a legislator, from eternal verities in an eternal mind that comprehends them and eternally possesses them. Bossuet cites St. Augustine, cites Plato himself, interprets him and defends him in advance against those who would make Platonic ideas beings subsisting by themselves, whilst they really exist only in the mind of God. _Logic_, book i., chap. xxxvi. "When I consider a rectilineal triangle as a figure bounded by three straight lines, and having three angles equal to two right angles, neither more nor less; and when I pass from this to an equilateral triangle with its three sides and its three angles equal, whence it follows, that I consider each angle of this triangle as less than a right angle; and when I come again to consider a right-angled triangle, and what I clearly see in this idea, in connection with the preceding ideas, that the two angles of this triangle are necessarily acute, and that these two acute angles are exactly equal to one right angle, neither more nor less--I see nothing contingent and mutable, and consequently, the ideas that represent to me these truths are eternal. Were there not in nature a single equilateral or right-angled triangle, or any triangle whatever, every thing that I have just considered would remain always true and indubitable. In fact, I am not sure of having ever seen an equilateral or rectilineal triangle. Neither the rule nor the dividers could assure me that any human hand, however skilful, could ever make a line exactly straight, or sides and angles perfectly equal to each other. In strictness, we should only need a microscope, in order, not to understand, but to see at a glance, that the lines which we trace deviate from straightness, and differ in length. We have never seen, then, any but imperfect images of equilateral, rectilineal, or isosceles triangles, since they neither exist in nature, nor can be constructed by art. Nevertheless, what we see of the nature and the properties of a triangle, independently of every existing triangle, is certain and indubitable. Place an understanding in any given time, or at any point in eternity, thus to speak, and it will see these truths equally manifest; they are, therefore, eternal. Since the understanding does not give being to truth, but is only employed in perceiving truth, it follows, that were every created understanding destroyed, these truths would immutably subsist...." Chap. xxxvii. "Since there is nothing eternal, immutable, independent, but God alone, we must conclude that these truths do not subsist in themselves, but in God alone, and in his eternal ideas, which are nothing else than himself.