It is easier to think in terms of the relationship existing between one point in time and another point in time. For example, now we think of then as then, but then we thought of then as now, although then was then now and now was then then. In other words, then was now, then, and now was then, then, though now is now now and then is then now. To clarify this, what was now then, is then now, thereby implying that now is now, now, but then was now then. You must also remember that then is not then then, but then is now but not then then, just as now is not then now, even though it was then then, when then wasn't then, but was now (then).
-Pope Gus Rasputin, Nuclear Platypus Biscuit Bible.