In the final analysis, to the extent they are inherently good, all of the laws and morality of our civilization are ultimately founded on Judeo-Christian beliefs, in other words, God's natural law.
The good news is that most Judeo-Christians are rational and will not enact laws that have obvious irrational consequences. Which means that the various religions (and the non-religious) can co-exist under a core set of laws that they find mutually beneficial, even though each sect thinks they were inspired for different reasons and causes.