“Quid est Veritas?” said Pilate. (“What is truth?”)
“Truth” is the correct correspondence of the mind’s conception of a perceived thing to the actual reality of the perceived thing. In other words, truth is when an idea accurately reflects the reality of a thing which that idea is representing.
Thus, truth only comes into play when there is a mind perceiving reality. If there were no minds, there would be no truth, even if there were still things in reality. Truth is in the intellect, as Aristotle said.
For this reason, some people think that radical subjectivism and relativism can be held. This is because we each perceive reality to differing degrees. Some people, for example, do not know that fornication is wrong, and thus, for them, fornication is not wrong. All things are relative, therefore, says them, because truth depends on the particular mind’s amount of knowledge of reality.
However, there is one mind that happens to know and perceive reality fully and completely. I am, of course, speaking of God. When we talk of “Objective Truth” it is the truth that God knows, and not just us (for we only perceive parts of this objective truth). Perhaps Objective Truth can be defined differently, but I cannot figure how. And for this reason, it would seem that atheists would be hard pressed to defend the existence of objective truth.
So when we speak of subjective truth, we mean that small part of objective truth that a particular person is perceiving. Sure, you could say that it’s not true that the “world is round” for certain ignorant people. But that is speaking subjectively, because subjective truth pertains to what is known by the limited knowledge of the given person. But objectively, it is true that the world is round, because, despite some people’s ignorance, the reality is that the world is round, a reality known by God. But if God theoretically didn’t exist, and no one knew the world was round, then it would not be true that the world is round, because no one would know it. For*, truth is the correct relation between an idea and a thing in reality*. There would be no relation, and thus no truth, because ideas can’t exist without a mind (well, actually, Plato would disagree … so if idealism is true, then there could be objective truth without God … but no Catholic theologians really would ever believe that … thanks to Aquinas and Aristotle).
Given that, there are still truths that are entirely subjective. For example, “Chocolate tastes good” is not objectively true. This is because, believe it or not, some people don’t like the taste of chocolate. Taste is a subjective experience. Different things are pleasurable to different people. It depends on the subject (i.e. the person perceiving the object). Relativists take this to an extreme and make the taste of chocolate apply to religion and morality, saying that worship and behavior is good if it suits your taste. That of course, is not objectively true.
So, in conclusion …
Objective truth pertains to the reality of how things really are despite anyone’s opinions, ideas, feelings to the contrary. We nonetheless can call this “truth” and not just “the way things are” because God’s mind fully perceives how “the way things are” and, since his mind does that, and a mind is necessary for truth, then we can call this “Objective Truth.”
Subjective truth only pertains to the reality perceived by a particular person. Subjective truth still exists (don’t get me wrong) but this does not mean that objective truth does not exist. They both exist. Objective truth, of course, is superior to any subjective truth, for it includes the entirely of reality and is relevant to all things that exist.
Does this help anyone? I hope this clarifies some issues.