"Every one will readily allow, that there is a considerable difference between the perceptions of the mind, when a man feels the pain of excessive heat, or pleasure of moderate warmth, and when he afterwards recalls to his memory this sensation,or anticipates it by his imagination. These faculties may mimic is copy the perception if the senses; but they never can entirely reach the force and vivacity of the original sentiment."

I agree that we can often recall a feeling that we will never forget, but we cannot reach the original perception of each feeling we have. I can easily recall that I was really warm sitting in class the other day, but until I feel that again, I cannot truly understand the sentiment. Memory often fades in and out throughout time, and unforunately that is somethign we cannot change.