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.e.that the run is not merely a multipliedfortuitous coincidence.What is meant by fortuitous and non-fortuitous ?CHANCE, CHANCES AND CAUSAL INDEPENDENCEIt is obvious that no run, however long, of heads in coin spinning orsixes in dice throwing is logically impossible.Any recorded frequencyis compatible with the assumption that the concomitances are in factfortuitous or that the run has been merely a multiplied coincidence.Norun proves unequireliability, i.e.proves that a causal law is operative.Yet quiteshort runs establish it beyond reasonable doubt.What does it mean to describe a distribution or a run as chance or fortuitous or as mere coincidence ? What is the connexion of meaningbetween chances , as we have been speaking of them and chance in thequite different sense of the fortuitous ?As we have used the expression the chance of or the chances of it wasa monosyllabic synonym for logical possibility.To say that a certainproposition yields certain chances simply means that that proposition iscompatible with the truth of any one out of a disjunctive set of otherpropositions.And this is quite different from the use of the word when wesay that something came about by chance or that a conjunction of eventsor properties was a chance conjunction.When given A, there is the chance or possibility of B, and the chanceor possibility of C; and when, further, there is no causal law ruling outA-cum-B or A-cum-C, then we can call the actual conjunction of A and Bor of A and C a chance conjunction.Thus Jones being blue-eyed yieldsthe chance that he has one Christian name, and the chance that he has two,and so on.And there is no causal inference from his being blue-eyed tohis having or not having two Christian names.So if he is in fact both blue-eyed and the owner of one Christian name, this conjunction is a fortuitousor a chance conjunction.Similarly it is a chance conjunction if a salmon isdead and lying north and south.Of course there is a cause for its beingdead and a cause for its lying in that direction; but there is no furthercausal law involved or if there is then it is false and so not nonsensical tosay that that conjunction was fortuitous.There is e.g.a cause for a compass152 COLLECTED PAPERS: VOLUME 2needle lying north and south.Conversationally we seldom describe statesof affairs as fortuitous unless there is some special motive (over and abovethe reasons) for denying it to be an example of one causal law, such as thatit is tempting to describe it as due to one cause.We call an unprearrangedmeeting with a friend fortuitous but not one with a stranger.For weexpect to meet some stranger or other in most of the places we frequent,but usually when we meet friends we do so by appointment.Conjunctions of events, properties, etc., when these are not to beexplained by reference to one cause, are chance or fortuitous conjunc-tions.It should be noticed that single events or states of affairs cannotbe and are not in fact ever described as fortuitous.Only concurrences arefortuitous or non-fortuitous.For by ascribing something to chance, weare not denying that it was caused, or even that we know its cause; onthe contrary we are ascribing it to a plurality of (causally and logically)independent causes.If we are wrong in thinking that the causes wereindependent, we are wrong in describing the composite state of affairs asfortuitous.In a word, the concurrence of A and B is denied to be fortuitous when itis known or thought that A is the cause or effect of B or that both areeffects of some one ulterior cause; it is asserted to be fortuitous whennone of this is the case.We draw attention to the fortuitousness of aconcurrence only when someone is inclined to believe that there is such acausal connexion, and so will be surprised to discover that there is none.Some theorists delight to aver that nothing is causally independentof anything else.This is wrong.Causal dependences are enormouslyrarer than fortuitous conjunctions.This thunder is the effect of that light-ning, but it is synchronous with countless other happenings, none ofwhich are mentioned in the scientist s explanation of why it thundered.Law-propositions explaining specific sorts of states of affairs ignore allbut a very few of the other things and happenings which are in factcohabitants with those states of affairs in the one physical universe.Every establishment of a law is also the tacit establishment of hostsof independences.Neap-tides are not the effects of elections, bird-migrations, foot-and-mouth disease, earthquakes.but of such andsuch.So they are just as much or little to be expected tomorrow, whetherthere is or is not an election or an earthquake today.It is sometimessupposed that a scientific discovery is always the discovery of a law.This isfalse.Much more often it is the discovery of an independence
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