"What is an engram you ask? Data free from matter."

Current science hotly debates if information can be destroyed. If you could measure everything, could you reconstruct a chair burnt in a fire? Of course this mostly has to do with astrophysics and the properties of singularities. If engrams are not physical, as Rahool attests, then they are something only someone who has a ghost can collect?

Did our ghosts res us based on an engram? A heroic moment, echoing through time? The weapons we find are strangely limited to the debased capabilities of the city. No wonder weapons, no intelligent munitions that fire before we are even aware of danger. Are they then echoes of the past as well?

Or perhaps a simpler explanation, that the city and Rahool cannot fabricate anything more complicated? Designs too complex are filed away and we are given shards to tide us over.

Each weapon then has a heroic or infamous history, which we discard for parts daily.

I'd love to see how fast that'd get cancelled

The Cryptarch has a line about this. Something like: "What's an engram you ask?! Matter from data! Ascendant matterials!"

"They are also sometimes thought of as a biological neural network or fragment of memory, sometimes using a hologram analogy to describe its action in light of results showing that memory appears not to be localized in the brain. The existence of engrams is posited by some scientific theories to explain the persistence of memory and how memories are stored in the brain. The existence of neurologically defined engrams is not significantly disputed, though their exact mechanism and location has been a focus of persistent research for many decades."

So we are decoding memories? Oh, guess who has biological mind cores? If it does turn out the Destiny universe is one big Vex simulation or any other kind of simulation, then Bungie will have forever dropped the ball on storytelling.

Say it ain't so.