From this brief review of the abstract or mathematical theories which have been proposed to explain the universe, it appears that while no one can deny the existence of gravity wherever there is matter, or of molecular activity or of motion, or of energy, it is certain that no one of them fully explains the mysteries of the universe. We feel the need of something more, some force or principle, some intelligence underlying all that we can see or discover as existing by the aid of the most powerful instruments, not only to direct and control forces already acting in and upon matter, but to create them and set them in motion.
Passing from these abstract explanations of the origin and nature of the universe and the consideration of their influence upon thought, four other theories, which may be called concrete from the fact that they rest on that which is visible and tangible, the morphological, the genetic, the vitalistic and the psycho-physical, require our attention. These theories are descriptive in their character and are based upon studies in the field rather than in the laboratory or the museum. Abstract science has been of immense advantage to the world of industry, and its methods of investigation will not soon be given up, but the progress made in the descriptive sciences has been very great and not without influence upon mind and life, or, as Merz is fond of saying, upon thought. The conception of energy and descent has helped to break down old distinctions and to establish on a firmer foundation the conception of unity in nature.
Morphology seeks to study objects as a whole rather than in detail, and to study these as they are in nature, before they suffer from changes wrought by the hands of men. The morphologist wants to know things as they are, and why they are. He recognizes the differences in the forms which substance assumes and in the structure of bodies. He considers their relation to each other and to their environment, the effect of climate and of time. But it is the object as a whole rather than any part of it in which he is interested. Such a method of study can not fail to be popular. It appeals to the people at large. Its descriptions can be easily understood and appreciated. Such men as Humboldt, Linnæus, Daubenton, Buffon and Cuvier have been among its distinguished advocates. Natural objects, it will be remembered, may be spoken of as cosmical, molar or molecular. Cosmical or heavenly bodies are magnitudes of immense size in space; molar objects are the objects we can see and handle here on the earth; molecular objects are the objects which are too small for our vision or touch to discover. Cosmical bodies are infinitely large, molecular infinitely small. If all bodies are similar in their composition, as the discoveries through the spectroscope seem to indicate, then a description of the nature of molar objects may be applied to those which are cosmic or molecular.
In the study of nature from a morphological point of view there is need of wide travel. Humboldt in his "Cosmos" has given us the re