A memora (plural memori) is has an expanded definition - it is defined as a memory, sensory input or any other stimuli. In effect the senses and memory are equated. This can be justified with either of the following arguements: 1) both are stimuli; 2) like memory, all that we observe is actually from the past (because it takes time for a stimulus to reach us and be processed by our brain). Beyond this, if esomnemism is accepted, observation and memory are exactly the same thing.
Our memori entirely define our experience. Thus, a realistic conception of the universe is completely dependent on the accuracy of our memori. Unfortunately, nothing can guarantee that our memori is accurate.