An absolute truth, sometimes called a universal truth, is an unalterable and permanent fact. The concept of absolute truths — what they are and whether they exist - has been debated among many different groups of people. Philosophers have waded in the muck of defining absolute truth for millennia. Alternatively, many believe in relative truths, where facts may vary depending on the circumstances.
It’s difficult to disprove the concept of absolute truth, since saying that there are no absolute truths - that it is absolutely true that no absolute truth exists - is itself an absolute truth. One can say, “From what I know, I believe there are no absolute truths.” Still, this is murky territory.
There are a few things that we all agree are absolutely true, but they depend upon an agreement in definition. Take, for example, the case where a person has a cat in his house. Obviously, no one would agree, as an absolute truth, that this cat, “was the nicest cat in the world.” However, most people would agree, given evidence that at that specific point in time, that there was a cat in the house. Some might quibble over the fact that people might define “cat” differently; that is, some might not describe a lion in a house as "a cat in a house."
People often look to science to determine whether something constitutes an absolute truth, but science tends to avoid absolutism. Even when scientists reasonably believe an explanation, it is often couched as theory or proofs. However, as we advance in science, we often find ourselves disproving proofs. Yet a great deal of proof on a subject makes it more likely, but does not make it absolute truth.
Many religions contain absolute truths. For example, a Christian might say, “ I know Jesus Christ is my Lord and Savior. By following his teachings, I will live in heaven when I die.” To the Christian this may be an absolute truth. Imposing this statement on others is where this absolute truth, to the Christian, becomes debated. While many may agree that the Christian believes absolutely that Jesus is his Lord, they are unlikely to agree that Jesus is everyone's Lord is an absolute truth. When a person’s absolute truth is extended to all others, it can be viewed as a philosophical statement of exclusion. Those who do not endorse the absolute truth of another are either pitied or attacked.
However, proper functioning societies and communities often rely on certain agreed-upon truths. For example, the US holds rape and murder as crimes and uses language to define rape and murder. Failure for a society to define such terms, and agree upon their definition could result in chaos.
Thus while absolute truths may be hard to come by, and difficult to agree upon, some amount of truths are generally required for a properly functioning society. Whether these truths are absolute or universal is a matter that has been and will likely continue to be debated.