第45章 Chapter II(16)

Mill's insistence upon this imaginary 'plurality of causes'is significant.It indicates the precise stage in the development of the idea of cause to which his doctrine corresponds.Taking what we may call the popular sense of causation,the 'plurality'expresses an obvious truth;and we can understand its plausibility.We take,in fact,two concrete events which follow each other,and call them cause and effect.We use a tool --a knife to cut bread,for example;we are forced to attend to the fact that every difference in the knife will have an effect on the result.The work is better or worse,as the knife is sharper or blunter.If we did not recognise this in every purposeful action,all action would be intrinsically uncertain.We are,therefore,impressed with the necessity of admitting that the effect is determined by the cause.But,on the other hand,the knife is there.It may have been made by fifty different methods,and yet be the same.The handle may have been first made and then the blade,or vice versa,and so forth.therefore we believe,and in this sense of cause believe correctly,that one effect may be the product of any number of different 'causes.'In order to reach the more scientific sense of causation,we have to take into account all that we have neglected.The knife is one product of an indefinite multitude of processes,and is therefore not the total 'effect'of the concrete antecedent,but only a part of it arbitrarily singled out.We do not attend to all these collateral results,because for us at the moment they have no interest;but when we systematically carry out the 'uniformity of nature'principle,it is obvious that they must be taken into account.We then see that although precisely similar products appear in an infinite variety of concrete processes,they correspond only to a part of those processes,and may always be analysed into identical elements.The effect can no more have two causes than a cause two effects,for cause and effect are distinguished by observing the same process in a different order.It was just because men of science held that the one effect must have one cause that they could make a coherent theory of heat.Mill,however goes a step further.Bacon's error was the assumption that there was only one 'form'of heat.Now it is specially futile,says Mill,to seek for the causes of 'sensible qualities of objects.In regard to scarcely any of them has it been found possible to trace any unity of cause.'Bacon,therefore,was seeking for 'what did not exist,'and to this Mill adds the surprising statement that 'the phenomenon of which he sought for the one cause has oftenest no cause at all,and,when it has,depends (as far as hitherto ascertained)on an unassignable variety of causes.'(74)To explain this rather startling assertion we must take one more of Mill's theories.How from the doctrine,which he fully admits,that every event has a cause can he reach the conclusion that some things have 'no cause at all'?Once more we have,Ithink,the misapplication of an undeniable truth.A 'law'of causation,taken by itself,will obviously not fully account for a single fact.It cannot lead to the conclusion:'this fact must exist,'but only to the conclusion:this fact must exist if certain previous facts existed.We somewhere assume an initial stage.However far back we can go,we may still repeat the question.Given a single state of facts and the 'laws of causation,'we can go indefinitely backwards or forwards in time.