Despite the strong case that Schopenhauer makes out, I am satisfied with my former advice—that a little thinking will suffice. Not only because, as already said, the reader will probably do nothing if advised to do more; but because after a certain amount of thinking has been done, it is more profitable to avail ourselves of the wisdom of the ages, stored in books, and to do our thinking after we have acquired the main outlines of this wisdom. For when we think a problem out, with the feeling that even after we have obtained a solution we shall probably find it in a book later, we have not the incentive that we have when we feel we have covered most of the old ground and that thinking may bring us into new territory. The practice of Gibbon remains to be considered: “After glancing my eye over the design and order of a new book, I suspended the perusal until I had finished the task of self-examination; till I had revolved in a solitary walk all that I knew or believed, or had thought on the subject of the whole work, or of some particular chapter. I was then qualified to discern how much the author added to my original stock, and I was sometimes satisfied by the agreement, sometimes armed by the opposition of our ideas.”[19] The trouble with this method is that it is not critical enough; that is, critical in the proper sense. It almost amounts to making sure what your prejudices are, and then taking care to use them as spectacles through which to read. We always do judge a book more or less by our previous prejudices and opinions. We cannot help it. But our justification lies in the manner we have obtained these opinions; whether we have infected them from our environment, or have held them because we wanted them to be true, or have arrived at them from substantial evidence and sound reasoning. If Gibbon had taken a critical attitude toward his former knowledge and opinions to make sure they were correct, and had then applied them to his reading, his course would have been more justifiable and profitable.