“I shall attempt to vindicate induction by showing that it is the only possible way of predicting that is objective, and further that, while objectivity is not a necessary condition for success in predicting, objective methods are the only methods which we could have any possible reason to believe possessed a property which is a necessary condition for success. This property I will call ”concordance“. An objective method is one that ensures that all whose use it will agree in their conclusions.... To say that a method is concordant is simply to say that there are no contradictory conclusions drawn from it. A method could possess this property as a consequence of its being objective; but on the other hand it is possible for a method of predicting to be concordant merely by chance.

If a predicting method is to be successful it must be concordant; for if there were a number of conflicting predictions made about the outcome of the one situation it would only be possible for one of them to be correct, and we should not describe as successful a method which had at least as many false applications as correct. Thus concordance is a necessary condition of success even in a single occasion of predicting. What, then is the relation between an objective and a concordant method?

It would be possible to have a concordant method by chance; for example, if a method should never be used to make more than one prediction about the outcome of any one situation it would ipso facto be concordant. Alternatively, the different predictions of a non-objective method may by chance agree. Thus objectivity is not a necessary condition of concordance nor, consequently, of being a successful method. However, in selecting a satisfactory method of predicting we must ensure that it is concordant. If we choose an objective method we do ensure this. Further, there is no other way of doing this; for by definition any method which of its nature is concordant is objective. The possibility of a non-objective method being concordant depends on contingencies beyond the control of the method or of any particular person who adopts it; for it is always possible for others to adopt the same method and make predictions about the same situations.

Thus, knowing that concordance is a necessary condition of a successful method and knowing that the only possible reason for expecting any method to be concordant is that it is objective, we may conclude that it is reasonable to adopt a method if it can be shown that it is the only objective method.“