Furthermore, even in writers far more consecutive in their thinking than Isidore, there are often fundamental preconceptions which are naively taken for granted, and which, although unstated, serve as points around which to mass ideas. If the reader does not happen to approach the subject with the same preconceptions, a misapprehension is likely to result. It is the business of the critic to grasp these preconceptions and place the reader on the same plane of understanding, as it were, so that he can follow the meaning as it lay in the mind of the writer. Sometimes this undertaking is possible, but in the case of a writer like Isidore, whose ideas are often hazy and whose work is a conglomerate of ten centuries, it may easily be impossible.[55] [55] For example, Isidore evidently had a theory as to the origin and value of language, but he does not state it anywhere, although innumerable times he approaches the subject in an oblique sort of way. See p. 99. Again, he never tells us whether he believed the earth to be flat or spherical; he uses at one time language that belongs to the spherical earth, and at another, language that can have sense only if he believed the earth to be flat. Here we have not only no definite statement of the conception—although it must have existed in his mind, considering the frequency of his writings on the physical universe—but we have in addition the puzzle of deciding which set of expressions used in this connection was meaningless to him. See pp. 50–54 and Appendix. However, it must be remembered that such an absence of an acute self-consciousness as is indicated in the condition just described, is exactly the thing that enables men to perform feats of an astonishing character in constructing a world-philosophy, if perchance they have a taste in that direction. Their minds, not being irritated or roused by any perception of inconsistency, rest happy in the conviction that all is explained, and remain oblivious of that sense of mystery which forms the background of modern scientific thought. As tested from this point of view the medieval period afforded the conditions for a complacent and authoritative world-philosophy, such as in fact it did possess. The difficulties in ascertaining the world view held by Isidore are, then, considerable; but, since he was the leading representative of the intellect of the dark ages, and the only important writer on secular subjects in two centuries of western European history, the attempt to ascertain it seems worth while. In making this attempt, however, it is necessary to keep these difficulties of interpretation in mind; the danger is that we shall lay too much stress on the minor inconsistencies which he probably was not aware of, and so fail to see that large general consistency which, because of his lack of critical sensitiveness, he was able to believe that he found.