stimulate the emotions, foster art; while economic progress which encourages the useful arts, and social conditions which emancipate the mind from tradition, are the great incentives to the development of science.

Origins of the Various Sciences. The discussion thus far has been confined to the origin and general effects of positive knowledge; it now remains to consider the more detailed effects upon progress of the separate sciences. The origin, or at least the early development, of each of the sciences may in almost every case be traced to an attempt to improve an art, or to obtain some specific object; and the chief service to society of these sciences has usually been the solving of those very problems which gave them their origin. A brief account therefore of the beginnings of the different sciences will open the way to a discussion of their effects upon social progress.

Astronomy. Astronomy was one of the oldest sciences to take definite form; and it is supposed to have originated in Egypt or Chaldea, although China has very old astronomical records. In Egypt the study of astronomy was probably first stimulated by the phenomenon of the overflow of the Nile, upon which Egyptian civilization depended. The exact time of its recurrence was a matter of importance, and the passage of time was most easily measured by the movement of the stars. The first study of the heavenly bodies, made to mark the passage of time, soon led to more detailed study for another purpose. It was noted that the Nile began to rise with the heliacal rising of Sirius, and this coincidence was easily mistaken for cause and effect. The conclusion therefore naturally followed that if Sirius had such an extraordinary influence upon the affairs of men, other stars must also have their influences. To ascertain the amount and character of these forces led to the study of astrology, which was long a center of attention, and which enlarged the knowledge of the heavenly bodies. Both in Chaldea and in China the desire to measure time accurately, as well as the wish to forcast the future, caused a careful study of the heavens. In Phoenicia the desire to obtain an accurate guide for travelling either by sea or land was the peculiar incentive to the study of the stars. The chief incentives to the study of astronomy then have been the desires to measure time accurately, to find dependable guides for travel, and to forsee the future. And the accomplishment of the first two desires has been of continuous service to society.

That astronomy first developed in desert countries where the air is clear and the stars are easily visible the greater part of the time, is a fact worth noting. These were pastoral countries, too, where shepherds could follow the movements of the stars either out of curiosity or to measure time. Astronomy would have had an early origin even if it had not been for the overflow of the Nile, yet it is doubtful whether under different atmospheric conditions it would have developed so soon.

Physics. The common laws of physics, as well as the simplest movements of the heavenly bodies, were known so early that we are unable to trace their sources. The Egyptians, again, were probably the first to study physical laws, for the pyramid builders must have had considerable mechanical as well as astronomical knowledge. Later engineering feats, such as the canal of Rameses and the various contrivances for controlling the waters of the Nile, would be considered creditable achievements even at the present day, and hence they show notable advancement in engineering skill and in knowledge of the laws of physics. Thus in early times interest in building and engineering enterprises fostered physics.

Chemistry. In ancient times chemistry was cultivated in a practical way in metallurgy in the manufacture of colored glass, and in the dyeing of fabrics. But interest was early turned aside from these practical needs to the visionary one of transforming the baser metals into gold. This quest of the alchemists was begun in ancient Egypt and was continued through the middle ages until the scientific awakening of the 16th century. On the whole it was more of a hindrance than a help to the advancement of chemical knowledge. A more profitable study lay in the search for curative agents. At first this took the fanciful form of a search for the elixir of life; but, after the time of Paracelsus in the 16th century, a more scientific attitude was fostered, and medicine became the chief medium for the advancement of chemical knowledge. Up to the 19th century the only laboratory of chemistry was the pharmacist's shop. In comparatively recent times chemistry has found other incentives, such as, for example, the desire to improve agriculture.

Biology. Chemistry and biology are more closely allied than any of the other sciences. Knowledge about both animals and plants was of course gained in prehistoric times in the search for food. But from ancient civilizations even down to modern times, the great stimulus to the advance of biological knowledge has been its value to the healing art. In ancient and mediaeval times almost all the contributors to biological knowledge were physicians with the possible exception of Aristotle, and it is doubtful if an exception should be made of a man who kept a pharmacy shop. At the Alexandrian museum the subjects of natural history and anatomy were carried on by the Faculty of Medicine, one of the four faculties originally established at the museum. In addition to medicine, agriculture furnishes a root for biology as well as for chemistry.

Psychology. In early times psychology had an obscure origin in metaphysics, but as an inductive science it is of recent growth. In addition to the metaphysical problems which the study of the mental processes were supposed to solve, two practical problems may be mentioned as stimulating the development of psychology. First, treatment of pathological mental states, which unites psychology with biology and chemistry, in that all three have their origins to some extent in medicine. Secondly, analysis of mental states and the course of mental development for the improvement of the intellect and the amelioration of human conditions through better methods of education.

Sociology. Finally, sociology arises from the desire to cure social ills and improve social relations, just as biology rests on the attempt to heal physical disease. This is not true of all the social sciences, especially not of economics which found its chief incentive in the attempt to increase the material wealth of one social group at the expense of other groups. Sociology, however, as a general science, has its chief root in the desire to heal. The existence of poverty, crime, labor disputes, and other

1 Wm. H. Welch, The Interdependence of Medicine and Other Sciences of Nature, Science, January 10, 1908.

social mal-adjustments, has stimulated an interest in the principles of human association and the laws of social development.

Order of the Development of the Sciences. This brief review of the social origin of the various sciences leads us to the problem of their effects upon social progress. To make this clear it will be advantageous to separate the sciences into three groups by diagonal lines, so to speak, the divisions not corresponding to the recognized boundaries of the different sciences. The first group includes astronomy, the greater part of physics, and lesser parts of chemistry and biology, and comprises what may be called the sciences of the environment. The second group includes a small part of physics and larger parts of chemistry, biology, and psychology and comprises the sciences pertaining to individual life. Sociology and a part of psychology form the third group and treat of social life. If the sub-sciences were included, the divisions would not be materially altered. A part of economics would be included in group one, as dealing with the environment, and a part of geology would fall into group two. These three groups may be designated for the sake of brevity as the natural sciences, the biological sciences, and the social sciences, dealing respectively with the physical environment, with individual life, and with social life.

The historical order of the development of the sciences is a complicated problem. Comte affirmed that they developed from the simplest to the most complex in the following order, astronomy, physics, chemistry, biology, and sociology; but such a serial order of development has been denied by Spencer and others. However this may be, in the three-fold division of the sciences which I have given, it seems clear that the sciences dealing with the environment developed before those dealing with life, and that the latter group developed before those dealing with society; and this is, moreover, the order of their present stages of advancement.

The development of the sciences seems to have been influenced, first, by the immediate interests of men, and, secondly, by the complexity of the phenomena investigated. These two factors account sufficiently for the relative stages of growth of the different branches of knowledge at different times. In early stages of civilization attention was concentrated chiefly upon the physical environment. To obtain a food supply and other necessities of life easily, to secure protection against enemies, to provide for the needs of the dead, and to satisfy the demands of the gods, were all important needs which stimulated a study of the environment and brought at least a practical working knowledge of the simple laws of mathematics, astronomy, and physics, together with a scant acquaintance with minerals and with vegetable and animal life.

The phenomena of life itself, the desire to live indefinitely and to overcome disease, focussed attention only a little later than the problems of the environment. But the phenomena of life proved much stranger and more complex than objects of nature which might be closely examined; and positive knowledge about them was slowly acquired. The heavenly bodies and other natural objects which were so far removed that their character could not easily be perceived, on the one hand, and living things which were so complex that they were not understood, on the other hand, remained objects of superstition and speculation much longer than familiar inanimate objects. The persistence of religious superstition materially delayed knowledge of human anatomy and disease, favoring rather the pursuit of astrology and alchemy. The anatomical studies of the Alexandrian school were in opposition to prevailing sentiments, and among the Arabians also the Mohammedan religion hindered the study of biology as compared with the other sciences. Biology, therefore, developed later than the physical sciences, not because it failed to attract attention, but because it was too complicated to be understood at an early stage of mental development.

The social sciences, on the other hand, developed last, both because they attracted little interest at an early period and because they dealt with complex phenomena. It is true, as Spencer points out, that some practical knowledge of social organization must have appeared at a very early time and conditioned, in a sense, all forms of progress. But this kind of knowledge was almost instinctive, like that possessed by gregarious animals; or, at least, it was a product of gradual experience. Before social organizations became complex they were not a subject of study