1. The qualities of a particular object, actually perceived, as in the case above cited, may be common to a variety of classes which we know, and also to others which we do not know. On the perception of such qualities, the Intelligence will suggest those classes only which we know, while the particular object perceived may belong to a class unknown. If, in such circumstances, a positive assumption, as to what class it does belong, is made, a wrong assumption must of necessity be made. The _Intelligence_ in this case is not deceived. It places the Will, however, in such a relation to the object, that if a positive assumption is made, it must necessarily be a wrong one. In this manner, multitudes of wrong assumptions arise. 2. When facts are before the mind, an _explanation_ of them is often desired. In such circumstances, the Intelligence may suggest, in explanation, a number of hypotheses, which hypotheses may be all alike false. If a positive assumption is made in such a case, it must of necessity be a false one; because it must be in the direction of some one hypothesis before the mind at the time. Here, also, the Intelligence necessitates a wrong assumption, if any is made. Yet it is not itself deceived; because it gives no positive affirmations as the basis of positive assumptions. In such circumstances, error very frequently arises. 3. _Experience_ often occasions wrong assumptions, which are attributed incorrectly to real affirmations of the Intelligence. A friend, for example, saw an object which presented the external appearance of the apple. He had never before seen those qualities, except in connection with that class of objects. He assumed, at once, that it was a real apple; but subsequently found that it was an artificial, and not a real one. Was the Intelligence deceived in this instance? By no means. That faculty had never affirmed, that those qualities which the apple presents to the eye, never exist in connection with any other object, and consequently, that the apple must have been present in the instance given. _Experience_, and not a positive affirmation of the Intelligence, led to the wrong assumption in this instance. The same principle holds true, in respect to a vast number of instances that might be named.