As you may know already, lucid dreaming requires performing “reality checks”, which is literally asking yourself within the dream, “Am I dreaming right now?”, performing other checks to confirm, and then enjoying the ride with various degrees of awareness.
Of course, it takes a lot of practice to get to this point of semi-lucidity within a dream to even ask such a thing. And even if you get there, you’ve performed the other checks, you’ve controlled your dream, you are still never sure it’s a dream to the extent as when you are awake that you are sure you’re awake, or that you had just been dreaming. It’s only when we are awake that we can be positively sure we were dreaming.
We don’t really think we’re awake when we’re dreaming – but we’re passively assuming wakefulness. We don’t doubt the dream inside the dream, and that’s the problem. It takes active consideration and practice to conclude that we are indeed dreaming. We cannot conclude, upon active consideration, that we are awake. So in a dream, when we actively consider, we conclude correctly – but we only achieve the absolute certainty when we awake.
So how does this carry over when we ask ourselves, in reality, to confirm our state of consciousness in reality? Like, “Am I in love?” for instance. It’s easy to actively consider these questions when awake; we may do it obsessively. And we get a lot of false positives, for the love question in particular. Yet when we know, we know. And we look back on that “knowing” as something entirely different than all those other times we thought we knew. Same how we know when we are awake. In both cases, we look back in awe at our naiveté.
But no matter how sure we now feel at the moment, we still can’t accept it as certainty for the same reason we can’t accept the certainty about our lucidity while dreaming. We still can’t truly know until we’ve woken up. But in reality there is no other level that we can “wake up” to. The closest we can do is conclude (rightfully).
So like what lucid dreaming is to regular dreaming, it seems like we have to achieve a state of consciousness beyond mere wakefulness to be able to look back and know what we were right.
It follows then that it’s only through experiments with consciousness that we can bring about the certainty we all desire.