The above division is certainly not complete and it is blurry at the edges. For one, the doxastic notion of probability has mostly been spelled out in a behaviorist manner, with the help of decision theory. Many have adopted so-called Dutch book arguments to make the degree of belief precise, and to show that it is indeed captured by the mathematical theory of probability (cf. Jeffrey 1992). According to such arguments, the degree of belief in the occurrence of an event is given by the price of a betting contract that pays out one monetary unit if the event manifests. However, there are alternatives to this behaviorist take on probability as doxastic attitude, using accuracy or proximity to the truth. Most of these are versions or extensions of the arguments proposed by de Finetti (1974). Others have developed an axiomatic approach based on natural desiderata for degrees of belief (e.g., Cox 1961).