If we all invoke the Categorical Imperative about something, we would all generally come to the same conclusion. Basically, something is only moral if it is done for its own sake or duty and nothing else. We must apply laws to ourselves that can also be applied universally. So if we set aside our desires and bias, we can use pure reason to find those ideas which have moral worth and separate them from those that don't. Calling it morality is a human invention yes, but we have these psychological processes in our brains due to evolution that cause us to act this way towards one another. Whether it be in hopes of reciprocity, survival, or unit cohesion, through the ages our ancestors have found it necessary to avoid harming one another as much as possible to survive. Who is more likely to survive, the person who killed off his tribe and has to face the wilderness alone, or the group who puts differences aside to hunt and gather for their mutual success?
That is where our built in idea of morality comes from and the Categorical Imperative is the application of that idea.
Morality is ultimately relative, but because it is relative it behooves us to then seek the best possible, i.E. Most logical morality for fulfilling our mutual interests. This means that out of relativism there is still an optimal moral system, it's just that it's not necessarily morally optimal but it is logically optimal and we have to base our decisions on something and we all (well enough people to make it work anyways) want to be happy, healthy, preservation of life, freedom... So it then makes sense to construct a logic-based morality. Getting it so precise that everyone will recognize one true morality as the most logical and everyone will be on the same page is something that's unlikely to happen. But theoretically something has to be the best.
I believe that universal morality does exist. Everyone is aware of what is right or wrong. Even people in different cultures share some type of values on this. People in Australia and the United States have a lot of differences in opinions but can agree that killing a person is wrong and should not be done.
In order for a moral/immoral action to exist, one must be able to differentiate the two. We can clearly see that killing a person is immoral and saving a person's life is moral. To disagree with this point means that the objector is not arguing on the same level and therefore that argument is non-falsifiable which in turn makes it untenable. Thus the argument. All actions that are moral or immoral are understood in relation to an action that is perfectly moral or perfectly immoral. There are different gradations on how moral an action is. It is clear that two actions may be moral but that one action may be MORE moral than the other. Based on this, to see this relation, both must be compared to something which is perfectly moral. Therefore, universal morality exists.
Morality is the intention not the action of an action, making it completely irrelevant. The majority of human morals are made through false hopes and childhood brainwashing. If there is truly absolute morality, then why do we disagree so much? The answer is because we all have a different moral code we go by. For example, Joe thinks we should make same sex marriage legal, because he views that denying their "human rights" is immoral, while Bob thinks it should be illegal because the act itself is immoral. The 2 men disagree with each other due to their moral differences. Neither of the men intend to be evil or mean, rather they grew up in a different environment, had different experiences, and they reason differently. The people we view as "evil" oftentimes believe they are doing good. We are often told by novels and movies that there is a clear good and a clear evil, but that is just not true. In real life, the "bad guys" don't have an evil laugh. If they did, no one would ever support them. In conclusion, to say that there is an absolute morality is very uneducated and close-minded. It's like saying you're always right.
Morality is a question that no matter what you ask is going to bring a different answer. I think there are bits and pieces that apply ac cross a wide range of religious, cultures, etc. But I think the more you look at it, the more everyone is going to have a different answer.
Morality is a human concept and one that is shaped by the culture and societies in which we live. There is no universal concept of morality, just a matter of means and mores that human beings live by. There is no sense of morality among the inanimate objects that make up the universe.