Third, a means to an end might have a very low probability  of helping to bring that end about.  Suppose, to take an example from  Jackson and Pargetter 1986, Professor Procrastinate has been asked to  review a book, which he both ought, and has reason, to do.  A  (necessary) means to reviewing it is accepting the commission to review  it.  However, even if he accepts the commission, he is very unlikely to  review it.  Professor Dispatch, in a parallel universe, is in the same  situation, except that he is very likely to review it if he accepts.   Perhaps Procrastinate, like Dispatch, has some reason to review it.  But  Procrastinate may not have as much reason as Dispatch to accept; not  all of the reason for the end may be transmitted to this (necessary)  means.  And it may not be the case that Procrastinate ought to accept.   This is an argument against Strong Reasons Necessity and Ought  Necessity, since even if one takes a necessary means, there may still be  a low probability of helping to bring that end about. However, it is  not an argument against the Sufficiency principles, assuming that  sufficient means, if taken, are sure to help to bring the end about.