He was 'writing what might be one important chapter in such a treatise,and supposes that he has written the whole,and can deduce 'philosophy'from it,if,indeed,any philosophy can be said to remain.Meanwhile,Imay observe,that by pushing his principles to extremes,even his 'association'doctrine is endangered.His Analysis seems to destroy even the elements which are needed to give the ******st laws of association.It is rather difficult to say what is meant by the 'contiguity,''sequence,'and 'resemblance,'which are the only conditions specified,and which he seems to explain not as the conditions but as the product of association.J.S.Mill perceived that something was wanting which he afterwards tried to supply.I will just indicate one or two points,which may show what problems the father bequeathed to the son James Mill,at one place,discusses the odd problem 'how it happens that all trains of thought are not the same.'90The more obvious question is,on his hypothesis,how it happens that any two people have the same beliefs,since the beliefs are made of the most varying materials.If,again,two ideas when associated remain distinct,we have Hume's difficulty.Whatever is distinguishable,he argued,is separable.
If two ideas simply lie side by side,as is apparently implied by 'contiguity,'so that each can be taken apart without change,why should we suppose that they will never exist apart,or,indeed,that they should ever again come together?The contiguity does not depend upon them,but upon some inscrutable collocation,of which we can only say that it exists now.This is the problem which greatly occupied J.S.Mill.
The 'indissoluble'or 'inseparable'association,which became the grand arcanum of the school,while intended to answer some of these difficulties,raises others.Mill seems to insist upon splitting a unit into parts in order that it may be again brought together by association.So J.S.Mill,in an admiring note,confirms his father's explanation ('one of the most important thoughts in the whole treatise')of the infinity of space.91We think space infinite because we always 'associate'position with extension.Surely space is extension;and to think of one without the other implies a contradiction.
We think space infinite,because we think of a space as only limited by other space,and therefore indefinitely extensible.There is no 'association,'simply repetition.Elsewhere we have the problem,How does one association exclude another?Only,as J.S.Mill replies,when one idea includes the idea of the absence of the others.92We cannot combine the ideas of a plane and a convex surface.Why?Because we have never had both sets of sensations together.The 'commencement'of one set has always been 'simultaneous with the cessation of another set,'as,for instance,when we bend a flat sheet of paper.The difficulty seems to be that one fact cannot be contradictory of another,since contradiction only applies to assertions.When I say that A is above B,however,I surely assert that B is below A;and I cannot make both assertions about A and B at the same time without a contradiction.
To explain this by an association of simultaneous and successive sensations seems to be a curiously roundabout way of 'explaining.'Every assertion is also a denial;and,if I am entitled to say anything,I am enabled without any help from association to deny its contradictory.On Mill's showing,the assertion and the denial of its contradiction,instead of being identical,are taken to be two beliefs accidentally associated.Finally,I need only make one remark upon the fundamental difficulty.It is hard to conceive of mere loose 'ideas'going about in the universe at large and sticking accidentally to others.After all,the human being is in true sense also an organised whole,and his constitution must be taken into account in discovering the laws of 'ideation.'This is the point of view to which Mill,in his anxiety to get rid of everything that had a savour of a priori knowledge about it,remains comparatively blind.It implies a remarkable omission.Mill's great teacher,Hartley,had appealed to physiology in a necessarily crude fashion.He had therefore an organism:a brain or a nervous system which could react upon the external world and modify and combine sensations.Mill's ideas would have more apparent connection if they could be made to correspond to 'vibratiuncles'or physical processes of some kind.But this part of Hartley's hypothesis had been dropped:and all reality is therefore reduced to the whirl of vagrant and accidentally cohering ideas in brains and clusters.His one main aim is to get rid of everything that can be called mystical and to trace all mental processes to 'experience,'as he understands experience --to show that we are never entitled to assert that two ideas may not be joined in any way whatever.
The general tendency of the 'Association Philosophy'is sufficiently clear.It may be best appreciated by comparing it to the method of the physical sciences,which it was intended to rival.The physicist explains the 'laws of nature'by regarding a phenomenon as due to the varying arrangements of an indefinite multitude of uniform atoms.I need not ask whether these atoms are to be regarded as realities,even the sole realities,or,on the other hand,as a kind of logical scaffolding removable when the laws are ascertained.In any case,the assumption is necessary and most fruitful in the search for accurate and quantitative formulae.Mill virtually assumes that the same thing can be done by breaking up the stream of consciousness into the ideas which correspond to the primitive atoms.What precisely these atoms may be,how the constantly varying flow of thought can be resolved into constituent fractions,is not easy to see.