Philosophically of course it is compatible with theism； but historians have for the most part desisted from invoking the naive conception of a 〃god in history〃 to explain historical movements。 A historian may be a theist； but； so far as his work is concerned； this particular belief is otiose。 Otherwise indeed （as was remarked above） history could not be a science； for with a deus ex machina who can be brought on the stage to solve difficulties scientific treatment is a farce。 The transcendent element had appeared in a more subtle form through the influence of German philosophy。 I noticed how Ranke is prone to refer to ideas as if they were transcendent existences manifesting themselves in the successive movements of history。 It is intelligible to speak of certain ideas as controlling； in a given period；for instance； the idea of nationality； but from the scientific point of view； such ideas have no existence outside the minds of individuals and are purely psychical forces； and a historical 〃idea；〃 if it does not exist in this form； is merely a way of expressing a synthesis of the historian himself。
15。 From the more general influence of Darwinism on the place of history in the system of human knowledge； we may turn to the influence of the principles and methods by which Darwin explained development。 It had been recognised even by ancient writers （such as Aristotle and Polybius） that physical circumstances （geography； climate） were factors conditioning the character and history of a race or society。 In the sixteenth century Bodin emphasised these factors； and many subsequent writers took them into account。 The investigations of Darwin； which brought them into the foreground； naturally promoted attempts to discover in them the chief key to the growth of civilisation。 Comte had expressly denounced the notion that the biological methods of Lamarck could be applied to social man。 Buckle had taken account of natural influences； but had relegated them to a secondary plane； compared with psychological factors。 But the Darwinian theory made it tempting to explain the development of civilisation in terms of 〃adaptation to environment；〃 〃struggle for existence；〃 〃natural selection；〃 〃survival of the fittest；〃 etc。 （Recently O。 Seeck has applied these principles to the decline of Graeco…Roman civilisation in his 〃Untergang der antiken Welt〃； 2 volumes； Berlin； 1895； 1901。）
The operation of these principles cannot be denied。 Man is still an animal； subject to zoological as well as mechanical laws。 The dark influence of heredity continues to be effective； and psychical development had begun in lower organic forms；perhaps with life itself。 The organic and the social struggles for existence are manifestations of the same principle。 Environment and climatic influence must be called in to explain not only the differentiation of the great racial sections of humanity； but also the varieties within these sub…species and； it may be； the assimilation of distinct varieties。 Ritter's 〃Anthropogeography〃 has opened a useful line of research。 But on the other hand； it is urged that； in explaining the course of history； these principles do not take us very far； and that it is chiefly for the primitive ultra…prehistoric period that they can account for human development。 It may be said that； so far as concerns the actions and movements of men which are the subject of recorded history； physical environment has ceased to act mechanically； and in order to affect their actions must affect their wills first； and that this psychical character of the causal relations substantially alters the problem。 The development of human societies； it may be argued； derives a completely new character from the dominance of the conscious psychical element； creating as it does new conditions （inventions； social institutions； etc。） which limit and counteract the operation of natural selection； and control and modify the influence of physical environment。 Most thinkers agree now that the chief clews to the growth of civilisation must be sought in the psychological sphere。 Imitation； for instance； is a principle which is probably more significant for the explanation of human development than natural selection。 Darwin himself was conscious that his principles had only a very restricted application in this sphere； as is evident from his cautious and tentative remarks in the 5th chapter of his 〃Descent of Man〃。 He applied natural selection to the growth of the intellectual faculties and of the fundamental social instincts； and also to the differentiation of the great races or 〃sub…species〃 （Caucasian； African； etc。） which differ in anthropological character。 （Darwinian formulae may be suggestive by way of analogy。 For instance； it is characteristic of social advance that a multitude of inventions； schemes and plans are framed which are never carried out； similar to； or designed for the same end as； an invention or plan which is actually adopted because it has chanced to suit better the particular conditions of the hour （just as the works accomplished by an individual statesman； artist or savant are usually only a residue of the numerous projects conceived by his brain）。 This process in which so much abortive production occurs is analogous to elimination by natural selection。）
16。 But if it is admitted that the governing factors which concern the student of social development are of the psychical order； the preliminary success of natural science in explaining organic evolution by general principles encouraged sociologists to hope that social evolution could be explained on general principles also。 The idea of Condorcet； Buckle； and others； that history could be assimilated to the natural sciences was powerfully reinforced； and the notion that the actual historical process； and every social movement involved in it； can be accounted for by sociological generalisations； so…called 〃laws；〃 is still entertained by many； in one form or another。 Dissentients from this view do not deny that the generalisations at which the sociologist arrives by the comparative method； by the analysis of social factors； and by psychological deduction may be an aid to the historian； but they deny that such uniformities are laws or contain an explanation of the phenomena。 They can point to the element of chance coincidence。 This element must have played a part in the events of organic evolution； but it has probably in a larger measure helped to determine events in social evolution。 The collision of two unconnected sequences may be fraught with great results。 The sudden death of a leader or a marriage without issue； to take simple cases； has again and again led to permanent political consequences。 More emphasis is laid on the decisive actions of individuals； which cannot be reduced under generalisations and which deflect the course of events。 If the significance of the individual will had been exaggerated to the neglect of the collective activity of the social aggregate before Condorcet； his doctrine tended to eliminate as unimportant the roles of prominent men； and by means of this elimination it was possible to found sociology。 But it may be urged that it is patent on the face of history that its course has constantly been shaped and modified by the wills of individuals （We can ignore here the metaphysical question of freewill and determinism。 For the character of the individual's brain depends in any case on ante…natal accidents and coincidences； and so it may be said that the role of individuals ultimately depends on chance；the accidental coincidence of independent sequences。）； which are by no means always the expression of the collective will； and that the appearance of such personalities at the given moments is not a necessary outcome of the conditions and cannot be deduced。 Nor is there any proof that； if such and such an individual had not been born； some one else would have arisen to do what he did。 In some cases there is no reason to think that what happened need ever have come to pass。 In other cases； it seems evident that the actual change was inevitable； but in default of the man who initiated and guided it； it might have been postponed； and； postponed or not； might have borne a different cachet。 I may illustrate by an instance which has just come under my notice。 Modern painting was founded by Giotto； and the Italian expedition of Charles VIII； near the close of the sixteenth century； introduced into France the fashion of imitating Italian painters。 But for Giotto and Charles VIII； French painting might have been very different。 It may be said that 〃if Giotto had not appeared； some other great initiator would have played a role analogous to his； and that without Charles VIII there would have been the commerce with Italy； which in the long run would have sufficed to place France in relation with Italian artists。 But the equivalent of Giotto might have been deferred for a century and probably would have been different； and commercial relations would have required ages to produce the rayonnement imitatif of Italian art in France； which the expedition of the royal adventurer provoked in a few years。〃 （I have taken this example from G。 Tarde's 〃La logique sociale〃 2 （page 403）； Paris； 1904； where it is used for quite a different purpose。） Instances furnished by political history are simply endless。 Can we conjecture how events would have moved if the son of Philip of Macedon had been an incompetent？ The aggressive action of Prussia which astonished Europe in 1740 determined the subsequent history of Germany； but that action was anything but inevitable； it depended entirely on the personality of Frederick the Great。
Hence it may be argued that the action of individual wills is a determining and disturbing factor； too significant and effective to allow history to be grasped by sociological formulae。 The types and general forms of development which the sociologist attempts to disengage can only assist the historian in understanding the actual course of events。 It is in the special domains of economic history and Culturgeschichte which have come to the front in modern times that generalisation is most fruitful； but even in these it may be contended that it furn