>>3525748All perceptions of the human psyche resolve into two distinct kinds, which I call impressions and ideas. The difference between them lies in the degree of force and vigor with which they hit the psyche and invade our thoughts and consciousness. Those perceptions that enter with the most force and violence may be named impressions: and under this name I understand all our sensations, passions, and emotions, when they first appear in the soul.
By ideas I mean these faint images in thought and reasoning. For example, it is all the perceptions that are excited by the present discourse, except only those that arise from sight and touch, and except for any immediate pleasure or anxiety it may cause. I don't think we need to use many words to describe this distinction. Everyone of us will quickly understand the difference between feelings and thoughts.
These general degrees are easily distinguished. It is not impossible, but in certain instances they may hardly approach each other. Thus, during sleep, during fever, during madness, or during very violent feelings of the soul, our ideas may approach our impressions. those from our ideas. However, despite this similarity in some examples, they are generally so different that no one can rank them under different heads and assign a unique name to each to indicate the difference
