I wish to discuss in this paper some of the problems involved in determining whether subjects on particular occasions are justified in coming to believe a proposition. I will argue that in attributing actual justification to a particular subject–subjective justification–we have to take into account factual-psychological questions and that these are the source of fundamental difficulties. These factual-psychological questions concern the beliefs someone uses in the process of acquiring another belief and the actual connections she makes among her beliefs.
But why should epistemologists be interested in making attributions of actual justification to particular subjects? After all, if the central goal of epistemology is to guide us in choosing rational strategies for supporting our beliefs, or to assess whether theories are well grounded or acceptable, epistemologists should be concerned with the justification a theory or proposition might have independently of anyone actually coming to believe it. This may be so, but it has to be shown that it is so. Moreover, the consideration of the factual-psychological questions involved in attributions of subjective justification seems to be necessary in some recent hybrid forms of naturalized epistemology. I call them ‘hybrid’ because, unlike Quine’s naturalized epistemology, they include in the epistemological task more than naturalistic explanations of how we acquire our language and beliefs. Besides taking into consideration the actual processes of our coming to believe or accept sentences, they also make use of epistemic notions like justification, warrant, relevant or right connection among beliefs, and so forth.