  That most of our knowledge is in memory at any particular time is a given.  What is perhaps surprising, however, is the degree to which even our current conscious knowledge typically depends on memory.  For example, you look at the sky and come to believe that the sunset is beautiful.  This is a newly formed belief about an event currently taking place.  Nevertheless, its justification is no doubt dependent on other beliefs that you hold.  For example, if you didn't at least tacitly believe that you were looking west or that it is evening and not morning, the belief wouldn't be justified (I assume that the phenomenology of sunsets and sunrises is indistinguishable). Now I am not, however, supposing that all knowledge of the external world is inferential. Your belief that the sky is red might well be epistemically basic.  Nor am I insisting that your sunset belief is psychologically inferential.  My only claim here is that many relatively simple beliefs we form about the external world typically depend for their justification on background beliefs; and background beliefs are memory beliefs.