The cause,therefore,is,'philosophically speaking,'the 'sum total of the conditions,'positive and negative,'taken together,the whole of the contingencies of every description,which,being realised,the consequent invariably follows.'(60)Mill's second amendment is made by saying that the cause does not signify simply 'invariable antecedence,'but also 'unconditional'sequence.There may be 'invariable'sequences,such as day and night --a case often alleged by Reid and others,which are not 'unconditional.'The sun,for anything we can say,might not rise,and then day would not follow night.The real condition,therefore,is the presence of a luminous body without the interposition of an opaque screen.(61)These are undoubtedly material improvements upon previous statements;and this view being admitted,it follows,as Mill says,that the state of the whole universe is the consequence of its state at the previous instant.Knowing all the facts and all the laws at any time we could predict all the future history of the universe.(62)Some curious confusions,it must be noticed,result apparently from Mill's use of popular language.The most singular is implied in his discussion of the question whether cause and effect can ever be simultaneous.Some 'causes,'he says,leave permanent effects;a sword runs a man through,but it need not remain in his body in order that he may 'continue dead.'(63)The 'cause'here is taken to mean the 'thing'which was once a part of a set of things,and has clearly ceased to mean the sum of all the conditions.'Most things,'he continues,once produced,remain as they are till something changes them.Other things require the continual presence of the agencies which produced them.But since all change,according to him,supposes a cause,it is clear that not only 'most things'but all things must remain as they are till something changes them.Persistence is implied in causation as much as change,for it is merely the other side of the same principle.Inertia is as much assumed in mechanics as mobility;for it is the same thing to say that a body remains in one place when there is no moving force,as to say that whenever it ceases to remain there is a moving force.The difference which Mill means to point out is that some changes alter permanent conditions of other changes,as when a man cuts his throat and all vital processes cease;while sometimes the change leaves permanent conditions unaffected,as when a man shaves himself,and his vital processes continue.But in no case is the effect produced,as he says,after the cause has ceased;it is always produced through the actually present conditions,which may have come into their present state through a change at some more or less remote period.Each link in a chain,according to the common metaphor,depends upon all the previous links and may be said to hang from them;but the distant link can only act through the intermediate links.
These slips imply a vagueness which leads to more serious results.Mill's aim is to construct a kind of logical machinery --a sieve,if I may say so,through which we pass all the phenomenal of the universe in order to find out which are really loose and which are connected by the ties of causation.We are unweaving the complex web of nature by discovering what is the hidden system of connections in virtue of which one event or thing is somehow fastened to another.Everything,we may say,which appears is called up by something else --the thunder by the lightning,the death by the poison,and so forth.In every case we can reduce a statement of causation to the form of an assertion of sequence or coexistence.Here,as he observes,we meet one difficulty.Everything is connected with some other thing.But then it may or must be also connected with a third.
