I know the Doctor was trying to figure one out, but I don't think he got much of anywhere with it.

But...aye. Being around him could have. And the socks that Sophie made me helped, too. Before that, though, after I came here. I started to have these dreams. Or, well, I thought they were dreams, at any rate. Bits of this mad life I'd not thought possible.

If the CAT has anything to do with your remembering now, maybe it helped things along to start with, and without it I'd not have remembered at all.