Real Memories belong to the entity that experienced them and are from their perspective (though the same scene may have several entities experiencing it from multiple angles). They come from direct participation in reality. Free Memories are those unattached to any entity, time, place, or item – but rather from the endless bounds of the Aether. Anything with some Essence can possess Memories.
Impression: Learning works by impressing new memories into the matrix of information, finding ways of cross referencing the information with everything else previously, and integrating it into current patterns and processes in order to build on it. Normal sapient creatures are good at this one one degree after another. The circumstances around the learning and social aspect of learning also make it easier for new ideas and facts to become integrated.
False-Impression: When the learning process is a memory imprint, a dream addled experience, or magically altered memory it lacks the shared social reinforcement. The most often that memory is used and referenced, the more often the character will notice incongruities in ho the memory got there and its meaning. Sanity checks may be required to persist the knowledge or power gained in this manner. Learning to read and wrote, research libraries, swing a sword in the dark, conjure forth a demon or call upon the aid of a divine spirit guide, or feel a locks tumblers move with your eyes closed. Places, times, dates, these never happened and could make things confusing when reconciling with real memory. Without shared memory of the world at large, the character will learn to question the reality of it and may end up losing the knowledge gained.
Memory impressions made by essentially branding the psyche from outside and permanently and traumatically inserting knowledge that cannot be forgotten and can only be recalled perfectly. It does not imply full comprehension unless noted, just enough to make use of them and trigger any effects related to them. In many cases, it is voluntarily accepted, and as such the source of the impression may also remove it, leaving only an empty memory with vague knowledge that it was once something the target had.
d20 [specific] Requirements:
Seared Impression Examples: Spell knowledge gained from Classes or Occult Slants (Arcane Trickster, Eldritch Knight, etc.) using Divine Sources or Warlock Patrons (Prime Entities).