Is Knowledge and Vision only retrospective?
Knowledge is the understanding of the destruction of the fetters of Craving, Conceit and Ignorance. Those are absent so long as Contact remains empty of a sense of Self; Desireless; and Signless.
When you see Contact with the Nibbana Element – post-Cessation – as being impermanent, not worth holding onto, and not-self (the Three Characteristics of Existence), the Feeling of relief that arises is also seen thus.
Because no energy of attaching a sense of self, craving and ignorance is given, the fetters dependent upon these, fade away, when the Defilements connected to them fade away as well.
Then Vision has arisen – that is Right View.
The retrospective action is the seeing of Dependent Origination from Formations onward, after Contact arises from post-Cessation.