The verb _to be_, is sometimes taken copulatively, although the relation expressed by it be not necessary: such is the case with all contingent propositions, and when the predicate does not belong to the essence of the subject. Sometimes the necessity is conditional, that is, it supposes a fact; and then there is no absolute necessity, since the supposed fact is always contingent. When we speak of ideal truths, we refer to those that express an absolute necessary relation, abstracting it from all order of existence; and on the other hand, we understand by real truths all those that suppose a proposition in which a fact has been established. To this class belong the truths of natural science, for they all suppose some fact which is the object of observation.
66. No real finite truth can be the origin of all others. Truth of this kind is the expression of a particular contingent fact, and consequently can neither include other real truths or the world of existences, nor ideal truths which refer only to necessary relations in the world of possibility.
67. Were we to see intuitively infinite existence, cause of all existences, we should know a real truth, origin of all others; but as we know this infinite existence only by discursion and not by intuition, it follows that we do not know the fact of that existence in which the reason of all other existences is contained. Neither is it possible for us, after having by means of discursion reached this cognition, to explain from this point of view the existence of the finite by the sole existence of the infinite; for if we abstract the existence of the finite, the discursion, by which we attained to the cognition of the infinite, disappears, and then our whole scientific fabric tumbles to the ground. Demonstrate to a man by means of discursion the existence of God, and require him, setting aside the point of departure, and depending upon the sole idea of the infinite, to explain not only the possibility, but also the reality of creation; and he cannot do it. If he only sets aside the finite all his reasoning fails, and no effort can prevent its failing; he is like an architect who, after having built a superb cupola, is required to support it although the foundations of the edifice are removed.