In accordance with the analysis of sympathy by Hume, Adam Smith made sympathy a leading concept in his theory of political economy. Smith also carried the concept of self-interest, with the resultant conflict between self-interest and social interest, into nearly all his economic theories. According to Adam Smith there are four classes of people in modern life. (1) There are those who live by taking rent. They have social interests but are not socially productive; they grow listless and careless. (2) There is the class which takes wages. This group is large, productive, and socially interested, but their widespread lack of education makes them subject to the passions of the day, and hence socially useless or even harmful. (3) Those who take profit have interests at direct variance with the welfare of society. Their selfish interests become unduly developed; their public attitudes are usually dangerous to all except themselves. (4) The fourth group is composed of all who derive a living from serving one or more of the three afore-mentioned classes. The interests of the three first-mentioned groups often clash, leading to destructive social conflicts. Despite this conclusion, Adam Smith was an advocate of _laissez faire_. He urged that natural laws be allowed to express themselves normally. In 1859, Moritz Lazarus and Heymann Steinthal began to contribute to social thought in the _Zeitschrift für Völker-Psychologie und Sprachwissenschaft_. They applied psychological methods to the study of primitive society. In this journal they made notable contributions concerning the social customs and mental traits of early mankind. It is in this field, which was discussed in Chapter XVIII, that the original work of such men as Franz Boas, W. G. Sumner, W. I. Thomas, and L. T. Hobhouse belongs. Fundamental pioneering in psycho-sociologic thought was done by Lester F. Ward (see Chapter XVII). Ward opposed the prevailing belief of his time, and particularly of Herbert Spencer, that society must continue as it now is going on, namely, an exhibition of a blind struggle of competitive forces. He not only perceived the rise of mind out of the obscure processes of social evolution, but more important still, he noted the part that mind may play in modifying the course of social forces. Although he considered the human desires to be the dynamic social elements, he gave to mind, through its power of prevision, the prerogative of directing the desires of mankind. Moreover, he pointed out the direction in which mind could best guide the desires. He urged a sociocracy in which the desires of the individual are so controlled that they operate only when in harmony with the welfare of other individuals. For establishing these fundamental considerations, Ward ranks high in the history of psycho-sociologic thought.