971 
of Edinburgh, Session 1883-84. 
in modification be observed and appreciated, but their modifiability- 
must be discussed and acted upon. Thus, in the case, when any- 
given environment or function, however apparently “ productive,” 
is really fraught with disastrous influence to the organism, its modi- 
fication must be attempted, or, failing that, its abandonment faced. 
After a thorough analysis of this sort we can attempt the treat- 
ment of such practical questions as the state of the poor, or the 
advancement of social progress in general — since practical action, at 
present dispersed into special efforts, each dealing with some aspect 
of organism, function, or environment alone (or of some mixture 
of these), must on pain of failure attempt the synthetic treatment 
of all.* 
It only remains to be pointed out that the ideals of human selec- 
tion which are beginning to be suggested on all hands, as biological 
conceptions penetrate modern thought, are to be worked out on one 
economic basis, that of adapting production to organism. 
Chapter III. — Psychological Principles. 
This department of the subject, unlike the two preceding, has an 
extensive literature, of which it is necessary to examine the main 
positions at the outset. 
§ 38. Pleasure and Pain. — A psychological basis for economics has 
often been sought in the theory of pleasure and pain — in the con- 
ception that we should find at once a theory of observed actions 
and a basis for expedient action in the pleasure or pain observed to 
attend them. Without disputing the possible high importance of 
this standpoint, or insisting too much upon the impossibility of 
verifying the measurements of pleasure and pain which Mr Jevons 
and Mr Edgeworth especially have used so freely, it must be 
pointed out that it is far from furnishing an absolute criterion. 
According to Spencer, “ pain is correlative of actions injurious to 
the organism, and pleasure of those which are advantageous.” But a 
* Le., all beneficent or benevolent agencies whatever thus fall into three 
genera, or rather brigades {e.g., ecclesiastical, charitable, educational, medical, 
&c. , into the first ; trades-unions, &c. , into the second ; associations concerned 
with hygiene, housing, art, &c., into the third). This classification, moreover, 
corresponds to the developmental succession of such agencies ; and this is now 
approaching an end, while the requisite co-ordination is becoming possible. 
