Now is now, right?
But back then, now was then, and now was in the future. Of course, now 'then' was back then, and was the past. In the future, now will also be in the past, as will then. But by then, then will be now and then will be the present. The future present, not the current present.
So, soon, when now is later, the then now will be then, and now will still be in the past. But by then we won't have to worry, because it will be now, and I've already told you what happened.
Every now and then you need to remember which now, which then, how long until then is now, or how long ago then then was now.
Then you can say that you did know now what you knew then. Of course, when you say now then, it will be a different now than now, because it will be then.
It's all very complicated now, but by then it will make perfect sense.
