Here is a quote from the Kuzari (the book) that struck me (paraphrasing the prophet Michah):
Obey the fundamental laws of ethics observed by even the most primitive societies, such as maintaining justice, helping the underprivileged, and thanking G-d for His bounty. You cannot properly fulfill the Divinely ordained laws unless you first observe the basic rational laws of ethics.
What is Michah and the book trying to say? By considering the greater context of the discussion, it seems to be arguing (something I've heard before) that after leaving Egypt, the Israelites needed to be succeed in those ethical laws before being judged worthy of standing at Sinai to receive the Torah: "These and similar [rules of ethics] are rational laws, [which you can yourself figure out]. They are the essentials that pave the way to the Divine Torah. No society can function without a code of behavior." In this way, the ethical mitzvot are prerequisites to Torah and the physical mitzvot.
Michah claims that Israel began to ignore the ethical laws during the time of the Second Temple. And that once those laws fell to the wayside, Israel didn't understand why they had to keep any of the laws, ethical or physical, and became unable to accept anything less than 100% certainty. However, life is uncertain. G-d is impossible to prove 100%. Even when you think you know something with absolute certainty, there can still be facts unknown to you. On the other hand, because nothing is certain, does that mean that you should throw everything out and believe nothing about the world, the universe, or G-d? Some do, and I can understand that. For the rest of us, we make the best decisions we can on the information we have. And I think that's still reasonable.
What's your take? Looking at the interplay between the physical and ethical sure is interesting! (And I apologize if this post is less than clear! I've only had a couple of hours of sleep!)
The prophet Michah is probably best known for the quote, "He has told you, man, what is good, and what G-d requires of you: only to do justly, and to love kindness, and to walk humbly with your G-d."