And the apparently non-extended speck which I see with the naked eye looks very different from the curious insect I see when I place a microscope over this speck, but I call them the same for the reason just given. If the insect as seen under the glass be divided, so is the speck as seen by the eye; if the insect is taken away, the speck disappears too. The series of percepts made possible through the microscope may be regarded as a continuation of the series which arises from approaching the eye to the object. Each member in it stands in a relation to this primary series similar to that illustrated above in the case of the telescope, and similar to that held by the terms of the primary series to each other. It should be kept clearly in mind that in all these cases the object (immediately perceived) is the same only in the sense pointed out, _i. e._, two or more percepts, which may, in themselves considered, be quite unlike each other, are recognized as in a certain relation to each other, as each representing the one series to which all belong. If one thinks he has reason to believe each percept represents not merely the series of percepts, but something different, which he infers and is pleased to call the "real" thing, he may be inclined to believe that in saying he sees the same object on two occasions he is referring to this something. It must be clear to him, however that all his evidence for the sameness of this something lies in the experience I have described, and it is to this that he must point in proof that it is the same. The percepts themselves are certainly not the same in any other sense than the one given. They are not identical, and they need not be alike. They merely stand for each other. Should one forget this, he will fall into blunders which I will illustrate at length when I speak of the common opinion on the subject of the infinite divisibility of space.