The problem with the concept of “absolute truth” is that we have no idea what it means. The notion of truth was developed in our languages because it has a very specific function in our lives: communicating the reliability of a statement of fact. When you say that something is true, you are stating that the other person can go and verify your statement. So it is a judgment about the reliability of a statement, nothing more.
As soon as you leave the pragmatic context of asserting reliability, you start to get into trouble. For instance, what is the truth of the statement “There is a lady in that room” if we cannot open the door? What is the truth of the statement “There will be a sea battle tomorrow” (Aristotle’s favorite example)? The answer is simple… we have no idea, and thus the notion of truth becomes useless in these situations.
Once you transfer the concept of truth to the domain of philosophy and spirituality, you run into an ever more serious problem… there is no method of verification, not even in theory, as there is with the lady in the room. What would it mean to “verify” a philosophical statement, such as “Being is said to be one”? Simply put, you can’t. This means that there is simply no truth in philosophy, because truth is a notion developed for a practical purpose that involves verification, and verification is impossible in philosophy.
The notion of “absolute” truth is even more problematic. What does “absolute” mean here? In the medieval era it mean “without consideration of something’s material or ideal status”, as Aquinas uses it. In German idealism, especially Hegel, it means “the unconditioned”, i.e. that which is not affected by anything else. But what would “absolute” truth mean here, when truth is all about other things: This or that thing is over there, in a room, on the roof. So the idea of truth as unaffected by anything else, i.e. absolute, is self-contradictory and thus entirely nonsensical.