Internalism versus Externalism in Epistemic Justification

The internalism/externalism debate concerns what kind of factors can determine whether a belief is justified. Access internalism, defended in different forms by philosophers such as Laurence BonJour, holds that justification-conferring factors must be things the subject can, in principle, become aware of through reflection alone, so that whether a belief is justified is always a matter the subject could in principle settle simply by introspecting carefully enough; this fits naturally with the classical, deontological picture of justification, discussed further below, on which being justified is a matter of believing responsibly, which in turn seems to require that the subject have access to the reasons that make responsible believing possible.