It may be further remarked that relative frequencies cannot be compared with 'degrees of certainty of our knowledge' if only because the ordering of such degrees of certainty is conventional and need not be carried out by correlating them with fractions between and I. Only if the metric of the subjective degrees of certainty is defined by correlating relative frequencies with it (but only then) can it be permissible to derive the law of great numbers within the framework of the subjective theory (cf.