The word “trodden” is usually translated as “to tread,” but that definition is actually quite different from what most people think of when they hear the word.
Once you’re walking through a place with no memory of where you are, you can’t tell when you’re there. You walk into a space that’s been filled only with a few people who walk around and talk about their lives. The memory of who you are and what you’ve done is the thing you remember most. It’s all just a snapshot of what you did when you got there.
In the end, trodden memory doesn’t mean the same as memory of something you have actually done (in a literal sense). You still have more than a few hours to walk through your own memory of a trip when you reach the end of the world, but you’ll have forgotten where youve been.
Memories are made up of smaller chunks of a much bigger thing. We have a lot of memory, but there is a lot more of what we remember. How much we remember is dependent on how much we’ve already been through. As a result, memory is very personal, and the more memories we have, the more we tend to get stuck in those memories, and forget what we’ve actually done in the present.