Defining Truth: Facts, Propositions, and Philosophical Criteria
Truth and Reality
The nature of truth, its relationship with reality, its types, and how to identify it have been fundamental problems in theoretical reasoning and, therefore, in philosophy. We consider facts and items to be true or authentic. However, we also believe our statements or propositions can be true.
Truth of Facts: Reality vs. Appearance
The distinction between reality and appearance has been a subject of controversy throughout the history of philosophy. However, a prevailing conception suggests that appearances hide reality. Things are not always as they seem. Appearances can deceive us and hide the real truth, preventing us from seeing how things truly are. In this view, truth is identified with the true reality, as opposed to the apparent reality. True facts are authentic facts, distinct from the apparent or deceptive ones. The search for truth is understood as a process of unveiling the authentic, which would otherwise remain hidden by appearances.
Propositional Truth
Truth is not only attributed to reality but, above all, to the claims we make about it. Understood this way, truth is a property that our propositions can possess. Just as we differentiate between types of propositions, we also distinguish between kinds of truth.
Truth of Empirical Propositions
Several theories address the truth of empirical propositions:
- Truth as Correspondence: A proposition is true when there is a match between what the proposition expresses and the reality to which it refers. The first proponent of this theory was Aristotle. Since then, numerous thinkers, like Descartes, consider a proposition true when it corresponds to the facts it indicates.
- Truth as Coherence: A proposition is true if it is not inconsistent with the rest of the accepted propositions. The first philosopher to suggest this was Friedrich Hegel. According to Hegel, the truth of a proposition is determined not by appealing to reality, but by its consistency with the rest of the propositions within a theory. Therefore, the consistency of a new proposal with those already known to be true indicates that the new one is also true.
- Truth as Success (Pragmatic Theory): This view considers a proposition true when it is useful and therefore leads to success. The truth or falsity of a proposition corresponds to the consequences that result from applying it. A proposition is true if its implementation yields positive results, whereas a false proposition leads to negative consequences. William James was the principal author of this theory.
Truth of Formal Propositions
Since formal propositions (like those in logic or mathematics) do not describe reality, their truth cannot consist in correspondence with it or in the usefulness of their application. Thus, for formal propositions, the only applicable criterion for truth is coherence. A formal proposition is true if it is consistent with the established rules and principles of the system (e.g., a mathematical system).
Criteria for Establishing Truth
How do we determine if something is true? Two main criteria are often discussed:
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Evidence: The word “evidence” comes from the Latin videre (to see) and refers to the clear way certain facts or propositions present themselves as obvious. Knowledge is considered evident when its truth is so apparent that it prevents doubt.
Limitations of Evidence:
This feeling of certainty and security accompanying evidence, which prevents doubt, is essentially a state of mind or feeling. Therefore, it is subjective – it belongs to the individual (“I know that I know”). Besides subjectivity, there are other reasons to question the adequacy of evidence as the sole criterion for truth. We often don’t know precisely what constitutes evidence, and it’s difficult to assess its power to guarantee legitimacy.
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Intersubjectivity: This criterion holds that for a belief to be admitted as true and contribute to knowledge, it must be acceptable to any rational subject. This approach is based on the idea that knowledge should be objective, shared by all, and not exclusive to one person. Truth, in this sense, is not private but requires community consensus.
Limitations of Intersubjectivity:
While consensus might be a necessary condition for accepting something as true within a community, it is not a sufficient guarantee of truth. Although true knowledge should ideally be acceptable to all rational subjects, the converse is not necessarily true: universal acceptance does not automatically make something true. Entire communities can be mistaken, as demonstrated by the widespread belief in geocentrism during Galileo’s time.