[Big Papa Goat]

"or can we safely and humbly assume that Physics has always existed as it is and that our understanding of it's nature has grown with time?"
"Morality is the Physics of man's interaction with itself."
hmm, so then morality hasn't always existed then right? Not that I'm saying you're wrong about morality being in some sense constant, I mean, no one has ever really wanted to say that morality is a historical/social construction.

All I'm really saying is that everyday morality is basically just sentimental, based on natural tendencies we've always had. Evolutionary psych seems to be exploring this kind of reasoning, but Adam Smith basically had it figured out a while ago based on common sense observations like the one about the guy hearing about a million dead Chinese people. I think this is basically as good a way to look at morality as any, even if it isn't very 'philosophical'. Now, you could say that the sentimentalist view of morality, particularly insofar as it is based on evolutionary psych is reductive and cheap for the reasons Emu laid out, but at the end of the day, what do you really want a theory about morality to be? I mean, this theory is descriptively fairly accurate right?

To get back to Preechr, you really do seem to be reaching at straws with the physics analogy, unless I really don't understand it. You say that our understanding of physics has grown over time, but physics itself hasn't changed because of that. True enough in that respect, Heidleberg uncertainty principle notwithstanding, but think about morality like that. Morality is how humans interact with one another, but the way people interact with eachother is tremendously influenced by the understandings of morality that the different people have. Obviously in the physics analogy you forgot that physics is how things do behave, but morality is how humans should behave. I mean, this is the first thing you have to remember to avoid the obvious problem that 'morality' in a descriptive sense (=the sense in which physics understands the world) is definitely depenendent on the (prescriptive) understanding of morality, insofar as the 'way humans interact' definitely does change depending on the way those humans feel they should behave. But if you want to be prescriptive, then you have to abandon to an extent the exactitude of physics, because the exactitude of physics comes from the fact that the human science of physics is the description of the non-human nature of physics.
Think about this; if you substitute your definition of physics for your use of the term physics in the sentence about morality you get something like this after you get rid of all the verbal junk: 'morality is the nature of man's interaction with itself'. Then, if we perform the same kind of operation on another sentence we get: 'some sorts of the natural interactions between men are more benefical than others' (after we remove the verbal junk about 'value', replacing that term with one that means something). At this point we're back to cost-benefit analysis though that Emu didn't like in the first place. The only difference seems to be that your cost-benefit analyses are going to be a lot more complicated because they want to deal with benefiting the entire human race.