Does culture shape law? Or does law shape culture? I say both. It's not an either/or scenario. People sometimes comment and ask this important question when learning about the rights-based Community Right's organizing and lawmaking strategy: You can make all the laws you want, but how are you going to make sure they're enforced?
My answer usually is that depends on the values of our culture. Here is an example, let's say you form a citizen majority and make a law giving a local river rights. If the majority of the people in the culture don't value the health and self-determination of the river the laws will mean nothing. It will eventually be killed or survive until this insane culture kills itself.
So I recommend to those concerned about the dance of law and culture my favorite two booklets available on the subject. They're the best tools that I know of to change both. Here are two quotes from them that I think offer us a good vision.
From On Community Civil Disobedience: "We can choose to be hospice workers to dying planet--seeking to ease its transition--or we can choose to be mid-wives to a different system waiting to be born." (pg. 49)
From The Book of the Damned: "Every creature born in the biological of the earth belongs to that community. Nothing lives in isolation from the rest; nothing can live in isolation from the rest. Nothing lives only in itself, needing nothing from the community. Nothing lives only for itself, owing nothing to the community. Nothing is untouchable or untouched." (Daniel Quinn, pg. 23)