Let C be any reasonable initial credence function. Let t be any time. Let x be any real number in the unit interval. Let X be the proposition that the chance, at time t , of A 's holding equals x . Let E be any proposition compatible with X that is admissible at time t . Then, C ( A | XE ) = x .
The Janus you choose makes the whole difference
Lewis 1986 :
Carnap did well to distinguish two concepts of probability, insisting that both were legitimate and useful and that neither was at fault because it was not the other. I do not think Carnap chose quite the right two concepts, however. In place of his ‘degree of confirmation’ I would put credence or degree of belief; in place of his ‘relative frequency in the long run’ I would put chance or propensity, understood as making sense in the single case. The division of labor between the two concepts will be little changed by these replacements. Credence is well suited to play the role of Carnap's probability1, and chance to play the role of probability2 .
Policy making is: 'the process by which governments translate their political vision into programmes and actions to deliver 'outcomes' - desired changes in the real world '.
This concern with achieving real changes in people's lives is reflected in the Government's overall strategy for improving public services published in March 2002
Promoting good practice in policy making is fundamental to the delivery of quality outcomes for citizens and to the realisation of public sector reform. Policy makers should have available to them the widest and latest information on research and best practice and all decisions should be demonstrably rooted in this knowledge .