FORMULAE OF SOCIAL PROGRESS 187 
or group! and the new complex rays resulting from various desire- 
belief combinations and oppositions are the mainspring of varia- 
tion and progress.? 
Tarde differs from Ratzenhofer in making the idea of a satisfier 
precede desire. He grants the impelling force of organic need but 
holds that this is a vital rather than a social factor. The social 
substance or thing invented or imitated is “‘ an idea or volition, 
a judgment or a purpose, which embodies a certain amount of 
belief and desire. Desire and belief: they are the substance and 
the force, they are the two psychological quantities which are 
found at the bottom of all the sensational qualities with which 
they combine, and when invention and then imitation takes 
possession of them in order to organize and use them, they also are 
the real social quantities.” * Belief and desire according to our 
author are not social forces until they come to a head in invention 
and are transmitted by imitation. But beliefs and desires are 
not always supplementary or co-ordinate, coming frequently into 
conflict and this fact leads Tarde to a discussion of the laws of 
opposition. 
The social forces thus classified drive individuals on by co-opera- 
tion and opposition, and by struggle and survival produce ulti- 
mately a more or less complete harmony. ‘“ Any aggregation 
whatever,” he says, ‘‘ is a collection of individuals jointly adapted, 
either some adapted to the remainder or all to a common func- 
tion. An aggregate means an adapiate. Moreover different 
aggregates which have relations with one another may be co- 
adapted; this constitutes an adaptate of a higher degree, and an 
infinite number of such degrees may be distinguished. For the 
sake of simplicity, let us distinguish merely between two degrees 
of adaptation; adaptation of the first degree is that which the 
elements of the system in question have among themselves; 
adaptation of the second degree is that which unites these ele- 
ments to the systems which surround them, that is, to what is 
1 The Laws of Imitation, p. 22. 
2 Social Laws, pp. 100 f. For Tarde’s use of “ imitation ” and his justifica- 
tion of it, including in the term counter-imitation, see Introduction, Les Lois de 
Imitation; also Social Laws, p. 42 n. 
8 The Laws of Imitation, p. 145. 4 Ibid., pp. 92, 93. 
