The appearance of Bayesian inductive logic has prompted a renewed optimism about the possibility of justification of inductive rules The justifying argument for the 'rides of such a logic is the famous Dutch Book Argument (Ramsey-de Finetti’s theorem) The issue winch divides the theoreticians of induction concerns the question of whether this argument can indeed legitimize Bayesian conditionalization rides Here I will be firstly interested in showing that the Ramsey de Finetti's argument cannot establish that the use of the mentioned conditionalization rides is the best option against Dutch Book betting strategies except in special circum stances I suggest secondly that some presuppositions of the Ramsey de Finetti’s theorem (for instance, the principle of maximization of expected utility) themselves demand a justification.