Imagination is the living power and prime agent of all human perception.

Seeing is not passive. What reaches you is fragmentary, and something in you assembles it into a scene, fills the gaps, and decides what the situation is before you have consciously considered anything. Two people can watch the same exchange and describe different events, both of them sincerely.

The practical use is a small habit of suspicion about your own certainty in everyday misunderstandings, particularly when you are sure what someone meant by a passing remark. Ask what else the same facts would fit. It is not doubt for its own sake, and not a reason to set aside a pattern you have seen many times; it is remembering that the vivid picture in your head was partly built by you.