The expression immaculate perception has been used in various senses by various philosophers.
It is a nickname for Plato's theory of knowledge. It is called this because Plato believed that all knowledge came from past lives, and from one's knowledge of The Forms.
It was used by the English philosopher Francis Bacon, who referred to it as the necessity of "keeping the eye steadily fixed upon the facts of nature and so receiving the images simply as they are."
It was used by the German philosopher Friedrich Nietzsche in his text Thus Spoke Zarathustra. Nietzsche argued that this kind of perception mere fiction, for it ignores the intimate connection between the perceiver and the external world. In particular, it denies the important role that the will and desires of the perceiver have on every perception.Metcalfe, Michael. A Dancer’s Virtue: Human Life in Light of Nietzsche’s Eternal Recurrence. Concept XXVIII, 2005.