Quantum probability from decision theory?

In a recent paper, Deutsch claims to derive the 'probabilistic predictions of quantum theory' from the 'non-probabilistic axioms of quantum theory' an d the 'non-probabilistic part of classical decision theory.' We show that h is derivation includes a. crucial hidden assumption that vitiates the force of his argument. Furthermore, we point out that in classical decision theo ry a standard set of non-probabilistic axioms is already sufficient to endo w possible outcomes with a natural probability structure. Within that conte xt we argue that Gleason's theorem, relying on fewer assumptions than Deuts ch, provides a compelling derivation of the quantum probability law.