"The world of Man's experience is infinitely rich and manifold, but chaotic and involved with the experiencing being. This being strives to arrange his impressions and to agree with others concerning them. Language and art, with their numerous modes of expression, are such ways of transmission from mind to mind, complete in their way where objects of the sense-world are concerned, but not well suited to the communication of exact ideas concerning the outer world. This marks the beginning of the task of science. From the multitude of experiences it selects a few simple forms, and constructs from them, by thought, an objective world of things. In physics, all 'experience' consists of the activity of constructing apparatus and of reading pointer instruments. Yet the results thereby obtained suffice to re-create the cosmos by thought. At first images are formed which are much influenced by observation; gradually, the conceptions become more and more abstract, old ideas are rejected and replaced by new ones. But, however far the constructed world of things departs from observation, nevertheless it is indissolubly linked at its boundaries to the perceptions of the sense, and there is no statement of the most abstract theory that does not express, ultimately, a relation between observations. That is why each new observation shakes up the entire structure, so that theories seem to rise and fall. This, however, is precisely what charms and attracts the scientist. The creation of his mind would be a melancholy thing, did it not die and come to life once more."