'Life' and 'sacred' are difficult concepts to accurately define (this is the whole stem-cell, abortion, IVF etc. debate). I prefer simply to say that it is wrong to cause harm - I don't think anyone could disagree with that axiom.

You have got to be kidding me. Assault?

I tend not to kill insects if I can avoid it. Not killing microbes would lead to a greater harm (disease) and hence is not immoral. Also, in both cases, the beings are not self-aware, hence the harm inflicted is minimal/

And I don't mind how long this goes on for. You will not win by wearing me down.

Sorry, I'm not particularly helpful because I do not support your goal.  From my perspective, the only thing more dangerous than some 'god-centered' moral system is some 'human-centered' moral system.

Morality just seems damn ugly all around - a game for charletans, mystics and authoritarians (with lots and lots of hypocrisy).

I'm with Nietzsche in so far as we are living 'beyond good and evil' now.  God is dead (humans killed him).  Since morality is defined by God, morality is dead as well.

That is to say, I don't see much benefit, purpose or advantage in seeking 'God-free' morality, since it will likely only produce the same monsterous violence, sanctimonious posturing, rampant hypocrisy and social-political unrest as 'God-driven' morality has always given us.

It doesn't.  Morality is a function of God.  God is immaterial.  Ergo, God-morality doesn't 'cohere' with a material world view.

Indeed.  Perhaps this is because it isn't actually sacred? 

Holding life to be sacred seems to be a 'polite fiction' of humans. Humans rarely actually adhere to this in reality (as Iamme's attempts to dodge my examples show).

We get 'natural selection' from nature.

And most existing moral systems do hold that the survival of 'their' culture supercedes human life as a whole.  Christianity famously celebrates and looks forward to the end of the world as a religious goal.

You are asking for a scientific reference for asserting that there are no universal moral systems?

Um... okay.  That's just odd on a couple of levels, not the least of which is the request to prove a negative, but also the appeal to science is rather strange given that this is a discussion of philosophy.

I'll just make a couple of points.

1. The moral systems used on this planet right now have NOTHING to do with evolution.  The Judeo-Christian moral system is about 2500 years old - that's when it was created. 

2. Yes, it is a convoluted mess.  Humans are messy creatures.  Postulating a higher power just for the purpose of endowing humans with some noble purpose and to make it all look orderly is the very definition of arbitary.  Jehovah, Allah or the Flying Spagetti Monster, take your pick.

I don't know.  Why don't you ask some Judeo-Christian what the docrine for that question is.

I think the Greco-Roman moral system was hunted down and exterminated by Judeo-Christians during the early centuries of Christian rule.

As for the "next one" it is already fully in effect now.  It is generally called moral relativism.

What mechanism is used for one moral system to supplant another is unknown to me.  All I know is the result.

That's moronically simplistic, wrong and nothing even close to what I've said.

It seems to me that you have given up trying to have a civil discussion and have decided that since you haven't gotten your own way, you ought to just denigrate and insult me instead.  No surprise there, this is a very common reaction from those who have never studied philosophy but presume to lecture people about it.

I do not discuss philosophy (or any other issue) with people who's arguments turn entirely into ad hominems as soon as they are challenged.

Welcome to P&R. May I take your coat?