There are several complimentary definitions of truth that contribute to a fuller understanding of its nature, but understanding it is very simple. If you know what a lie is, the truth is just the opposite.
Sound simple? Like a game of chess, knowing the nature of the game does not necessarily make the game itself simple to master. Thankfully, we all have a good deal of practice at this game, because we play it all the time.
The truth can be described as the set of all propositional statements (statements of fact) that correspond to the way the world actually is. In other words, any statement that accurately reflects the world around us is true. This is called the correspondence view of truth.
Another view of truth states that a set of propositions must also be self-consistent; that is, two statements that deal with the same circumstances in the same relationship cannot contradict each other and be true. This is called the coherence view of truth.
Of course, some—maybe even most—truthful propositions lie outside of the experience of any given individual. To know the truth of scientific, medical, and legal concepts, for instance, we rely on the authoritative knowledge of competent and trustworthy experts in the field: in these cases, scientists, doctors, and lawyers. This is called the authority view of truth.
There are other views of truth that are currently gaining public acceptance in our society. How do they compare with the common-sense views already discussed?
Some currently hold, either knowingly or unknowingly, that truth may not be the same for all people. What’s true for one person, they say, may not be true for someone else. This view is sometimes called relativism, because truth is relative to the individual. It is also called subjectivism, because truth is determined by the subjects (or individuals) involved in the situation, rather than the objective components of the situation (the circumstances).
This view, though, cannot satisfy its own qualifications for truthfulness. The claim that any given proposition is true for one person but may not be true for another must also apply to the statement, “Any given proposition is true for one person but may not be true for another.” Therefore, it must also be true that, for someone, no propositions are true for one person that are not true for another. That person’s view, though, contradicts the rule, so the rule cannot be true. In the words of Greg Koukl of Stand to Reason, the view commits suicide.
Other views, particularly those of Eastern religions, hold that truth is ultimately unknowable, since the world as we experience it is an illusion. Again, this view cannot be true, since the statement “Truth is unknowable” is itself a truth claim that those who offer it actually hold to be true. Knowing the truth that truth is unknowable is self-contradictory. It is simply and inescapably false.
Truth is not and cannot be
unknowable, and truth is not and cannot be reduced to each person’s private
experience. If it’s not those things, it
must be both knowable and objective, with existence outside of those who
observe it.
Truth matters because error is dangerous. There are particular facts about the world that are deadly if you get them wrong or don’t know about them. For instance, not understanding the theory of gravity will not allow you to survive a jump from a 100-story building without some restraint system. Gravitation is true; it actually exists. Knowing about it and taking the appropriate actions to avoid its negative effects is not only wise; it’s practical and essential.
While some truths about physical things are readily observable and repeatable, there are some truths that can be discovered about things that are not physical. We know, for instance, that non-physical things such as thoughts, immaterial selves, and emotions exist because we have them and experience them directly. We can arrive at more complex truths about things like logic, mathematics, and philosophy through careful study and reflection. Other things, particularly spiritual things, may require an outside authority to intervene and educate us.
Just like with physical things, error in spiritual things can be deadly. Having a firm grasp on the truth will protect a person from making serious spiritual errors that can and will place their soul in jeopardy.