Plato versus Aristotle’s theory of knowledge What elements of their epistemologies are you specifically referring to? I imagine perhaps you are trying the conceptualize Aristotle's and Plato's Metaphysical disagreements which manifest themselves in their epistemologies? I.E. The concept of Forms and the material.
So here is my perspective:
1. Plato's Forms as only true sources of knowledge:
Problem: Is there one form or an infinitive number? If there are indeed a discrete number of forms, why does not everything have a form (then the number of forms would be infinite). Do individuals not exist? If you "know" (through experience or other) an individual, do you not know the essence (form)?
2. Aristotle's material Individuals as constituting conceptual existence of philosophical objects
Problem: So, yes, physical sensation informs us of the material existence of an individual person or thing, but under these philosophical constraints we cannot know if this thing necessarily exists in any other sense than in which it exists for us (as Plato points out in his dialogue Theaetatus, I believe)
So, essentially, the main question is the classic One-Many argument AND how can we know? We can perceive by touching/experiencing things, but is this really a valid source of "knowleldge"? And just because I "see" something outside, does it mean that it necessarily must exist? - What if I am dreaming, etc.?
Hope this helps