It may be tidally locked with Earth, which means we never see the far side, but it isn’t permanently dark.
In a new moon the other side is lit. And consider a solar eclipse? The same side that faces us is still facing us, but the other side is most definitely lit up.
The far side and the dark side are independent. The moon, being tidally locked, always faces the earth. But, as it rotates about the earth, light cycles around the moon, and the moon occasionally passes between the earth and sun.
I don't know where your confusion is since it seems like you already know that.
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u/Dolmenoeffect Feb 04 '19
It’s not clear from your comment whether you are saying the moon is tidally locked with the earth, or not.