Book excerpt: This volume is a study addressed to professors and students interested in the philosophy of language. It is generally accepted, though in not sufficiently rigorous terms, that doxastic dialectics can be defined as being an exchange of opinions. Given the subjective rationality of doxa, the traditional doctrine uncovers philosophical limitations in this regard. Instead of minimizing the heuristic power of doxastic dialectics, this book looks at whether it might be possible to affirm doxa’s cognitive autonomy regarding episteme, focusing on the mechanism of decidability in doxastic thinking. The text advances three cognitive theses: that doxastic dialectics engenders cognitive intervals between belief, opinion and doxa; that doxastic dialectics opens conditions for an alternative truth, semantically constituted, not analytically proved; and that doxastic dialectics is the exclusive procedure by means of which the fundaments of axiology can be established.