Truth cannot be absolute. The reason the truth cannot be absolute is that things in life are constantly changing.
What was true before may, due to varying circumstances in both environments and human behavior, become false or untrue.
For example, there was a time when it was true that if you had a tattoo you would be ostrachized and ridiculed, and socially affiliated with a gang or nefarious group or organization of some kind.
While some people may still hold that sterotype as true, many people no longer due.
The condtions of society and the dynamic of human interaction have altered perceptions considerably, and it is within perception itself that the attributes of truth exist.
Were truth a stagnant thing, it could easily be rendered absolute, and the very nature of this question rendered pointless.
Truth is a reflection of human perceptions, and due to the technology, politics, and environment that humans find themselves in, conditions and qualities regarding truth change.
Another example is couples of different races having children.
In the United States it was illegal for interracial copies to marry, let alone reproduce.
Yet now in 2008, it is not illegal, and as each day passes you see more and more of that occurring. As times change and conditions change, so to do the truths of our times change.
There also was a time when reading was illegal for African Americans, and yet now libraries and universities and Borders and Barnes and Nobles are run and maintained by African Americans as well as shopped at invested in.
The point being, there is a huge gap in experience when the time does not allow for a group to read, using the threat of death to keep that segment of the population willfully ignorant, to when that group is allowed not only to read, but to write, to work in places where books abound, etcetera, etcetera.
This example illustrates my point on how truth is conditional and not absolute.
If anything is absolute, it implies a stagnant state, especially when regarding a very exclusive human notion such as truth.
Dogs and cats do not think in terms of truth and lies. In their universe, it is either real or it does not exist.
Metaphysical concepts by definition cannot encompass the absolute, because if ever there were a idea or experience that contradicted them seen as valid, by the very definition of what an absolute entails, that value system would be perceived as invalid after evidence contradicting the absolute validity of that system was presented and assessed.
That is why I think religion has many problems adapting to a highly technological society and the constant exchange of information that occurs within such a society.
The absolute nature of most religions exclude any conditions that may invalidate them, and hence most religions deem themselves absolutely true, and oppose other religions which also claim absolute truth.
However, truth, as I stated very early on, is a condition of perception, exclusive to human beings. As human beings and their experiences change, so to do human truths.
Regardless of the perceptions behind a given perspective, the idea of truth as absolute can only be applied to religions. And even within the framework of relion those who worship the same God may not do so the same way. They may differ, and they differ because the truth is conditional, not absolute.