Answer:
What has four legs during the day; and six or eight during the night?
It regulates our daily movements, but it feels no interest in our lives. It directs us when to come and go, but does not care if we pay attention. What is it?
I can be written, I can be spoken, I can be exposed, I can be broken.
A dagger thrust at my own heart, dictates the way I'm swayed. Left I stand, and right I yield, to the twisting of the blade.
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
What never gets any wetter no matter how hard it rains?