One difficulty I see for contemplating the meaning of truth here is that the several ways of looking at it are all mushed up together in this discussion. On the one hand, some are discussing how one discovers or knows truth, while on the other hand some are talking about the abstract or objective meaning of truth. It might help to clarify things if truth were broken down into the main ways it is considered.
I would begin by distinguishing two primary perspectives on truth: 1) objective, or what is true apart from human perception of truth, and 2) subjective, or what is discovered to be true through human perception; I would also further break down the subjective perspective to mundane, logical, and absolute.
The objective meaning is most difficult to define. To say what is true irrespective of human perception is to say what exists. What actually exists, and I think we have to include what has the potential to exist, is the whole of what is true. If it does not exist, and cannot exist, then we can say it is not true or real. So in terms of objective truth, it’s a derivation of existence. For instance, light (in our universe) exists, so it we say it is “true” light exists, and it is also not true that light doesn’t exist. What exists has no relationship to whether or not we know it exists or affects us . . . it just is. Whatever that objective realm of existence is has been pondered and debated for thousands of years, just as it is now. Is existence at the most basic level monistic, and all the “things” we observe just forms this most basic level of existence has taken? Or is the most basic level of existence multifaceted? Is part of it conscious, or does raw mechanics prevail at all levels?
Moving on to the subjective perspective, because we are conscious, we know things and ourselves exist. We know existence affects us, we want to understand how existence works, and we wonder about the ultimate nature of existence; these three aspects of our awareness determine the three sub-categories of subjective truth. So “mundane” truths are those aspects of existence which are personal, like it is “true” I prefer asparagus to lima beans, that I need x amount of money to pay my mortgage, and that I am most comfortable in a temperate climate. These elements of my existence may not be true for someone else, but they are true for me. Then there is my attempt to understand how the objective universe “works.” Because it appears that at least the physical universe works in an orderly way, logic and reason operate superbly to reveal certain objective truths to our subjective awareness so we can interpret, predict, and develop the practical means for interacting with the physical universe. This is where axioms, proofs, empiricsim, etc. have the most relevance. Finally, there is that very difficult ontological question of the ultimate or absolute nature of our own existence. Are we purely physical, or is there something “more” behind the physical? This is truly the most challenging truth to know. Some say logic, reason and sense observation can answer this, while others say only some deep inner experience reveals the truth about the nature of our absolute existence.
