This is from Harold Pinter's Nobel acceptance speech last year (if you haven't seen/heard/read it, I highly recommend it -it's available both as a transcript and as a video). He's talking about truth in art, but these are wise words for any planner.
"The search [for truth] is your task. More often than not you stumble upon the truth in the dark, colliding with it or just glimpsing an image or shape which seems to correspond to the truth, often without realising that you have done so. But the real truth is that there is never any such thing as one truth in dramatic art. There are many. These truths challenge each other, recoil from each other, tease each other, are blind to each other."
Keep seaching. Keep looking. Keep asking. Keep sifting. Keep thinking. Keep distilling. Keep being curious.