"Someone must have created those rules.
On a related note, wouldn't you look at the laws of physics and our incredibly complex universe and say the same thing?"
Absolutely not, they are two seperate issues entirely. Laws of physics are external to ourselves, as do not require sentience IN AND OF THEMSELVES to function. I think you would agree that now, once the universe is in motion, no God is needed to push the sun across the sky, it's self-running. However, morality requires sentience. And if morality is written into the fabric of the universe then we have a sentient guiding force.
"If moral truth does not exist, then why is it wrong to kill someone?"
Wrong to kill someone according to who? According to gravity? According to electromagnetism? No, according to us. Hence it is internal. There are some actions that must, by neccesity, be restricted in order for society to function. We are, by nature, societal animals. Hence, we tend to restrict certain behaviors. A society cannot exist, for example, when murder is condoned. Noone would trust each other and the society would collapse. Perhaps small bands of people would continue to exist, but only such bands where it is acknowledged that murder is not acceptable. Morality is not a function of the universe at large so much as it is a function of our need for groups.
"Animals have no moral code. There is no right and wrong. If a monkey steals a bannana from another monkey, he feels no pang of consious."
Have you ever seen a dog's face when it craps inside the house and knows it shouldn't have? It reacts in a way humans would equate with genuine shame and guilt. Ever seen a cat's reaction when you come home from a long trip? It reacts in a way humans would equate with genuine affection and loneliness. Animals have emotions. And, in animals which develop active societies and social bonds (canines, for instance) conscious does indeed develop. A sickly wolf in will be tended for by its pack. When wolves fight, it is not often to the death, it's until one surrenders, and then the victor will do no more harm to it. A wolf which has no loyalty to the pack will be ostracized and expelled from the group. Are these actions you would expect to see in a creature totally devoid of moral sentiment?
There have been recorded instances of a child actually surviving in the wilderness into adulthood. They have no sociel experience, and, as a result, no moral code. I'll look up these cases for you if you like.
People brought up with no moral upbringing tend to view morals much more lightly. If it truly is inborn we shouldn't expect to see this reaction. Yet, truly amoral people do exist. My grandmother saw someone break another man's head open because he wanted to see what brains looked like. Would you suggest that they have no soul?