One of the first difficulties in interpreting Hume’s epistemological writings concerns precisely the meaning of the words ‘knowledge’ and ‘belief’. In this article it is shown, initially, how, from a humean point of view, the traditional epistemic criterion to define ‘knowledge’ and ‘belief’ appears very restrictive. Hume’s theory of causal belief is then briefly reviewed in the light of epistemological naturalism of the Michael J. Costa and Louis E. Loeb. Finally, it is submitted that the examination of all these topics (...) lends support to the Hume’s naturalistic theory of justification of beliefs. (shrink)