Toward a Universal Truth?

I've been looking, for the past few years, for a universal truth. A moral absolute that transcends geographic and cultural boundaries; an undeniable commonality...up until now I've been pretty unsuccessful, but I never stopped looking. Every time I thought I had a theory I would always find a valid argument against it. I thought "thou shalt not kill" would be a moral absolute; but then I encountered the self defense and Jus ad Bellum justifications. I thought surely rape, slavery, gender equality, etc. would be regarded universally around the world, but further investigation proved that these concepts are culture bound.

Earlier I was reading a summary on the English School of International Relations and I stumbled upon this: An author named John Vincent in his book Human Rights and International Relations posited that a person has the right to not go hungry; that no one should be denied basic sustenance. The impact of Vincent's assertion should not be taken lightly for this reason: Since the beginning of civilization mankind has struggled to find a common ground in the field of International Relations; a universal belief of a single human right can lay the groundwork for future cooperation amongst state actors. Unfortunately ideological deviations between states have hindered any progress in this area. The fact that Vincent was bold enough to identify an area for universal acceptance inspires hope. Author Andrew Linklater writes of Vincent's theory

[Vincent] argued that the right of the individual to be free from starvation is one human right on which all states can agree on despite their ideological differences. Vincent argued that a global action to end starvation is essential since the absence of the basic means of sustenance should always shock the conscience of humankind. Consensus on this matter would be a significant advance in relations between the Western world, which has traditionally been concerned with order rather than justice, and the non-Western world, which has always stressed the need for greater justice.

So will this be the one moral absolute that will be the "silver bullet" in International Relations? Probably not, but it's a start. And considering that I thought a universal truth was impossible, I'm starting to like our odds.