According to this, the order in which changes succeed each other in real objects becomes known to us as objective only by their causality. This assertion Kant repeats and explains in the "Critique of Pure Reason," especially in his "Second Analogy of Experience,"[99] and again at the conclusion of his "Third Analogy," and I request every one who desires to understand what I am now about to say, to read these passages. In them he affirms everywhere that _the objectivity of the succession of representations_--which he defines as their correspondence with the succession of real objects--is only known through the rule by which they follow upon one another: that is, through the law of causality; that my mere apprehension consequently leaves the objective relation between phenomena following one another quite undetermined: since I merely apprehend the succession of my own representations, but the succession in my apprehension does not authorize me to form any judgment whatever as to the succession in the object, unless that judgment be based upon causality; and since, besides, I might invert the order in which these perceptions follow each other in my apprehension, there being nothing which determines them as objective. To illustrate this assertion, Kant brings forward the instance of a house, whose parts we may consider in any order we like, from top to bottom, or from bottom to top; the determination of succession being in this case purely subjective and not founded upon an object, because it depends upon our pleasure. In opposition to this instance, he brings forward the perception of a ship sailing down a river, which we see successively lower and lower down the stream, which perception of the successively varying positions of the ship cannot be changed by the looker-on. In this latter case, therefore, he derives the subjective following in his own apprehension from the objective following in the phenomenon, and on this account he calls it an _event_. Now I maintain, on the contrary, that _there is no difference at all between these two cases, that both are events_, and that our knowledge of both is objective: that is to say, it is knowledge of changes in real objects recognized as such by the Subject. _Both are changes of relative position in two bodies._ In the first case, one of these bodies is a part of the observer's own organism, the eye, and the other is the house, with respect to the different parts of which the eye successively alters its position. In the second, it is the ship which alters its position towards the stream; therefore the change occurs between two bodies. Both are events, the only difference being that, in the first, the change has its starting-point in the observer's own body, from whose sensations undoubtedly all his perceptions originally proceed, but which is nevertheless an object among objects, and in consequence obeys the laws of the objective, material world.