What we have so far sought to show has been (1), generally, that an attempt to define the real by distinction from anything else is necessarily futile—the result of a false abstracton from the distinction between the real nature of one event or object and that of another—and (2) specially, that the antithesis between the real and the work of the mind is invalid, not because the real is the work of the mind—whether it is so or not we have yet to enquire—but because the work of the mind is real. The mere idea of a hundred thalers, to use the familiar instance, is no doubt quite different from the possession of them, not beause it is unreal, but because the relations which form the real nature of the idea are different from those which form the real nature of the possession. (§ 24 ¶ 1)

So much it was necessary to show, in order that the enquiry, whether it is due to understanding not merely that we are able to conceive a nature but that there is such a thing as nature at all, might not be prejudiced by a preconception which would make it seem equivalent to an enquiry whether the real could be the work of the unreal. If now from the futile question, What is the real? which we can only answer by saying the real is everything, we pass to one more hopeful—How do we decide whether any particular event or object is really what it seems to be, or whether our belief about it is true?—the answer must be that we do so by testing the unalterableness of the qualities which we ascribe to it, or which form its apparent nature. A certain hill appears to-day to be near: yesterday under different conditions of the atmosphere it appeared to be remote. But the real nature of the event which took place in yesterday’s appearance cannot, we judge, thus change. What it was really, it was unalterably. There may have been a change from that appearance to another, but not a change of or in whatever was the reality of the appearance. The event of yesterday’s appearance, then, must have been determined by conditions other than those which determine to-day’s. But if both appearances depended solely on the position of the hill, they would be determined by the same conditions. Therefore we must have been wrong in believing the hill to be so remote as we believed it to be yesterday, or in believing it to be so near as we believed it to be to-day, or in both beliefs: wrong in respect of the relation which we supposed to exist between the several appearances and the distance of the hill. (§ 24 ¶ 2)