248. "God is truthful," says Descartes, "and could not have deceived us; He could not have taken pleasure in making us the victims of perpetual illusions." All this is true. But the skeptic will ask how we know that God is truthful, or even that he exists. If we found the veracity of God on the idea of an infinitely perfect being, as Descartes does, there is still the same difficulty with respect to the correspondence of the idea with the object. If we draw the demonstration of the veracity and existence of God from the ideas of necessary and contingent beings, of effect and cause, of order and intelligence, we again meet the same obstacle, and are still unable to pass from the idea to the object. No matter how much we cavil, we shall never get out of this circle, we shall always return to the same point. The mind cannot think out of itself; what it knows, it knows by means of its ideas; if these deceive, it has nothing left to set it right. All rectification, all proof must employ these ideas, and these, in their turn, require new proof and rectification. 249. Many books of philosophy exaggerate the illusions of the senses, and the difficulty of assuring ourselves of the sensible reality, when they solve this question: "I perceive it to be so; but is it as I perceive?" These same books immediately afterwards speak of the order of ideas with security equal to their mistrust in the sensible order. This does not seem very logical, for phenomena relating to the senses, may be examined by the light of reason, and it may be seen how far they agree with it: but what touch-stone have we for the phenomena of reason itself? If there be difficulty in the sensible, there is likewise in the intellectual, and the more serious, since it affects the very basis of all cognitions, even those which relate to sensations. If we doubt the existence of the external world which the senses present to us, we may appeal to the connection of the sensations with causes not in us; and so deduce by demonstration the relations of the appearances with the reality: but this requires the ideas of cause and effect; we must have some truth, some general principles, as for example, that nothing can produce itself, and others similar, without which we cannot take one step. 250. We do not believe any satisfactory reason can be given for the veracity of the criterion of evidence, although it is impossible not to yield to it. The connection, therefore, of evidence with reality, and consequently, the transition from the idea to the object, are primitive facts of our nature, a necessary law of our understanding, the foundation of all that it contains,--a foundation which in its turn rests, and can rest only on God, the Creator of our soul.