But data, even tables of dates, have no value in themselves; it is only from their relations to other things that they have value. There would be no value, for instance, in knowing that William of Normandy invaded England in 1066, unless we knew who William was, and what England was, and what the effect of his invading it was. Now the thoughtful man, like the man who arranges a card-catalogue in such a way that it will be useful, not only notes isolated facts, but puts them into juxtaposition with each other, and sees what their relations are. The mental pictures that he finally fixes in his mind are of related things, seen in their correct perspective. They are like the pictures which are made on the mind of anyone by--say, a landscape: whereas the mental pictures made by an unthoughtful man are such as little children probably receive from nature; pictures in which the trees and hills and valleys of a landscape do not appear as such, but merely as a great aggregation of numberless separate images, confused and meaningless like the colored pieces of a kaleidoscope. To the thoughtful man, therefore, life seems not quite so meaningless as to his neighbor; though even the most thoughtful can fix very few complete and extensive pictures in his mind. If his thoughtfulness takes him no further than simply forming pictures that enable him to see things as they are, and in their correct relations to each other, he becomes "a man of good judgment," a man valuable in any community, especially for filling positions in which the ability to make correct deductions is required. Such a man, however, no matter how correctly he may estimate any situation, no matter how clearly he may see all the factors in it, no matter how accurately he may gauge their relative values and positions, may be unable to suggest any way for utilizing its possible benefits, or warding off its possible dangers. That is, he may lack constructiveness. He is like a man who possesses any desirable thing or dangerous thing, and who understands all there is to understand about it, but _does not know what to do with it_. The various factors are in his (mental) hands, but he can make nothing of them. The constructive man can construct concrete entities out of what are apparently wholly individual factors having no relation to each other; he can, for instance, take two pieces of wood and a piece of string, and make a weapon with which he can kill living animals at a considerable distance. With neither the pieces of wood nor the string could he do that; and he could not do it with all three, unless he were able to construct them into a bow and arrow. That is, he could make the weapon if he had ever seen it made before. If he were only constructive and not inventive, he could not make it unless he had seen it done before, or knew it had been done.