Abstract
The paper argues for viewing legal validity as a doxastic obligation, i.e. as the obligation to accept a rule in legal reasoning. This notion of legal validity is shown to be both sufficient for the laywers' needs and neutral in regard to various theories of the grounds of validity, i.e. theories intended to identify what rules are legally valid, by proposing different grounds for attributing validity. All of these theories, rather then being alternative definitions of validity, presuppose the notion here provided.This notion is purely normative, but it allows for the construction of theories of the grounds of validity which give due importance to social expectations and institutions. As an example of how this may happen, one such theory is also provided. This theory, which is presented through a detailed example of a judicial debate, is based upon the recognition of the (instrumental) value of co-ordination, as the necessary way to achieve the most valuable purposes of the law.