[1] Does the existence of logic point towards the supernatural?

If you're not into philosophy, please pardon this post:

It seems everywhere one goes, one picks up new identities. I was never so aware of my Asian American identity before arriving at Michigan and architecture wasn't even part of my life back then... kinda incredible to think about, actually. Imagine a me without architecture...

I also picked up another title that I now identify with. Skeptic. I know I grew up questioning everything around me: my parents, my faith, the church, my friends. When I got to college, I started to question myself. One of my worst fears in the past was to be following any sort of belief or living any sort of life blindly. I guess I can say that I am successfully living a life which has been thoroughly questioned, but I also cannot be happy with the mindset I've developed about things. It's become hard to trust, hard to make decisions and way too easy for me to be cynical about everything.

A couple days ago, in the car, my dad was on one of his rants about life and... motivation and... grades and... medical school and... what a good student he was and.... ...then on to how as a non-Christian in med school God was leading him towards Himself and Christianity.

I, ever the devil's advocate, started to pose questions. It seemed like from what he was saying, there wasn't really enough reason for him to have made the leap from med school to faith in Christ. I wanted to know if I was missing something. We began to talk about the human body, creation and the reality of a creator not only in Christianity but in many religions. Eventually our discussion turned to the topic of logic and reason.

"Logic is such an interesting thing. We use it to understand and prove everything else, but there's nothing we can use to prove the dependability of logic itself. If there isn't anything outside of this physical world and our human existence and human logic, then we have no reason to trust our own logic and there's no reason for us to be having this discussion at all. For this world to make sense, logic must originate before human thought in a supernatural realm."

I was familiar with the sort of argument he was posing. I'd used it before, in relation to morality and talking about how morality might prove the existence of a supernatural god. There are two responses I have always received and so I posed the same objections. First, couldn't logic be relative? I mean, what's logical in one situation and culture is not always considered logical somewhere else. Could logic be determined by society? Second, why couldn't logic have evolved as a means for survival? Logic as a way of creating order and discussion as a way of sharing and obtaining ideas in order to better one's own logic and way of living. Does logic necessarily have to come from the supernatural?

My dad was quick to refute the first response by dismantling my question. In his argument, if logic is relative then there's no reason to be using it to try to understand anything and there was no point in us continuing our discussion or our search for a right answer. A right answer could not exist. People always argue relativity but by the act of arguing for relativity, they see it 'as truth': relativity is right, absolute truth is illogical. If there is 'a truth', then not everything is relative. It's the flaw in Nietzschian thought. If logic does not exist, then how could you write a book about it's non-existance by using logical arguments?

For the second argument, he had nothing to say. By then we had reached home. he dropped me off and left to go help a friend move out of her house. He told me to find an answer for my own question.

This is the response I came up with:
What makes survival the appropriate (logical) direction to go? Is life then better than death? Is there something good about living and bad about dying? If logic is relative then neither survival or death would be the more logical direction to go, and evolution would not strive towards survival.
(My assumption is that logic must be relative in a world without the supernatural because there is no absolute truth to define what is correct or incorrect logic... )

Of course our discussion had ended by then and so that's my final thought. Does the idea of evolution make sense under its own parameters? (Of course the skeptical part of me is asking 'Am I missing anything? Am I making any other assumptions? Is my question fair?')

What do you think?