made science and philosophy and are making it. The need of solving a problem is a real practical need. How much science should we at present have if there had not been a large amount of that human restlessness, which we call interest, on matters of theory.
This scientific uneasiness depends upon a capacity for discovering problems and being worried by them. The presence of some unexplained, uncomprehended thing is a cause of effort, of striving, of using up energy. The energy is expended for a purpose, the solving of the problem; and of various solutions that may offer themselves that one is accepted as the best which calls for the smallest expenditure of energy. The elegant demonstration is the one which makes use of few resources. Clearness and transparency of method and result mean usually that relatively little effort is needed to understand them.
Let us admit then, for the purpose of this discussion, that the principle of economy is the guiding principle in science, and that the principle of least resistance is its parallel principle in nerve-tissue.
Every special science seeks to get what it might call a valid experience of its objects, and this means that it tries to get the objects pure and uncontaminated by any personal equation. No doubt the principle of economy leads, to a certain extent, to a misrepresentation of objects, but this is the ignoring of what is regarded as irrelevant from the point of view of the special interests, whereas a subjective enrichment of the object is the putting into it of what might make a difference in the description. This much seems clear, science feels at liberty to ignore as much detail in the objects as it is not interested in, but it denies the right to add anything.
Now if we admit that the special sciences are seeking to get their objects pure and if we imagine that there is a special science for each region of phenomena, and if we call this experience of pure objects a pure experience, then the special sciences are collectively aiming at a pure experience of the world.
This was the meaning of pure experience as Avenarius used the term in his 'Philosophic als Denken der Welt Gemass dem Princip des Kleinsten Kraftmasscs, ' and it is one of the meanings of the term in the ' Kritik der Reinen Erfahrung. ' But since such a pure experience is defined from an epistemological and not from a psychological point of view, the concept does not appear in the same form in the later work.
The special sciences are distributed, each to its own field. Within each field, novel facts are comprehended by reducing them to a group of known facts, which group undertakes to be as small as possible. In the same way the effort to understand the world would be the
