substantial accord (Lois soc., p. 6). Each proceeds from the simple to the complex, from the general to the special. The sciences in their hierarchical order are mathematics, astronomy, physics, chemistry, physiology, and psychology, rising to a culmination in sociology, which now claims the sceptre once wielded by theology.
By 'sociology' the author means the philosophy of the particular social sciences (Lois soc., p. 31). The essential and qualitative difference between social phenomena and biological or psychological phenomena is found in contract. "Reciprocal consent appears for the first time in social phenomena." Until then they are not distinguishable from vital and mental phenomena (Introduction, vol. I, p. 131). Social, like all other phenomena, may be arranged in an hierarchical order of increasing complexity and speciality. The groups recognized are economic, generative, artistic, phenomena of belief, moral, legal and political (ibid., p. 214). The main objects of the Introduction to Sociology are to prove the existence of sociology and that its phenomena may be hierarchically classified (ibid., p. 24). But these two aims seem to be fundamentally one, since a science is really constituted when its classification conforms to rational laws (ibid., p. 159).
The classification of the sciences is an example of what M. de Greef understands by a sociological law, i.e., a necessary relation between a phenomenon and the conditions of its appearance (Lois soc., pp. 35 ff.).
The author's most recent work is divided into two parts, the first part dealing with the growth of individual beliefs and doctrines concerning progress, the second aiming to discover from the life of society the main laws regarding social changes. He finds that social beliefs regarding progress are correlated with the character of collective life. "In times of decay pessimistic beliefs and theories attend upon other forms of social depression. In times of real progress optimistic beliefs and theories arise " (p. 512).
The author desires to see the social sciences introduced into the curricula of primary, intermediate, and high schools, as well as of the university. One cannot but question whether in their present state of development their disciplinary value to young students would be at all comparable to that of the studies displaced.
In M. Tarde's previous work, Les lois de l'imitation, étude sociologique, published in 1890 and dedicated to Cournot, one of the chapters is on the logical laws of imitation. The present work is an amplification and continuation of the opinions sketched in that part of the earlier volume, and cannot be fully comprehended apart from its predecessor.
May we have a science or only a history of society? If a social science is possible, why is it yet unborn? Mainly because its heralds have been
