Truth

[gL.edu] This article gathers contributions by Stefan Willibald, developed within the context of the Conceptual clarification about "Information, Knowledge and Philosophy", under the supervisión of J.M. Díaz Nafría.

Overview

Truth is an essential concept for the basis of most philosophies and every-day live. But regardless of its importance to the present day it is not possible to completely describe, what truth is, or what the nature of truth is. This article is supposed to give an overview over the most popular theories concerning the nature of truth.

Truthbearers

It is useful to talk about the questions: "What can be true?" or "What can have a truth-value?" at the beginning. The truth-value is binary, either "true" or "false". There are many candidates for sorts of things that can have truth-values, eg sentences and propositions, etc.

Sentences

When we talk about sentences, we normally talk about sentence-tokens: concrete linguistic objects that are written or spoken, like "The snow is white." But there is another philosophical entity connected to sentences the sentence-type: abstract objects that stand above all sentence-tokens, that state the same.

For example:

• The snow is white.
• The snow is white.
• The snow is white.

These are all different sentence-tokens of the same sentence-type.

There are several arguments supporting sentence-tokens as possible truthbearers. Sentence-tokens have no issues with "indexical" terms like personal pronouns, as they always refer to a certain entity. So when one says "I like blue" and he likes blue the sentence-token is true and if the person saying the sentence doesn't like blue, the sentence-token is false. If we would try the same with the sentence type "I like blue." we would have a serious problem, as both sentence-tokens refer to the same sentence-type, the sentence-type would have to be both true and false - an unacceptable contradiction.

A Problem concerning sentene-tokens as truthbearers is, that sentence-tokens are manmade objects. This means, if sentence-tokens were the truthbearers and there never had been any language-users, then there would be no truths. Another problem is the relative low number of sentence-tokens. If one considers, for example, the number of different ways that a deck of cards can be arranged. The number 8x10^67 is so humungous that there will never be enough sentence-tokens in the world to describe each unique arrangement.

So we have difficulties with our theory of sentence-tokens or sentence-types as truthbearers, but what about propositions?

Proposition

To escape the dilemmas from sentence-tokens and sentence-types, propositions are usually suggested as truthbearers. The term proposition is used in several different ways, for example to describe the meaning of a sentence. Like two different sentences, that mean the same would be considered to express the same proposition.

For example:

• "The snow is white." English
• "Der Schnee ist weiß." German

Both sentences express the same meaning, even though they are different sentence-tokens and different sentence-types.

One of the critics about propositions is the problem, that we can't determine the actual meaning of a sentence, nevertheless if two sentences have exactly the same meaning. Therefore the relationship between propositions and sentences is yet a serious philosophical problem. Despite this problems propositions are one of the most popular entities as truthbearers, probably also because of the ambiguous meaning of the word.

Major Theories

There are countless Theories about Truth, but they can mostly be related to one of the following mayor theories.

Correspondence Theory

The Correspondence Theory could be stated as:

A statement is true, if, and only if, the underlying proposition corresponds to a fact or object.

To make sense this requires a setting of metaphysics that include facts or objects as part of an objective reality (see Realism). These prerequisites are one of the mayor critics concerning this theory.

Coherence Theory

The Coherence Theory could be phrased as:

A belief is true, if , and only if, it is part of a coherent system of beliefs.

So it is sufficient for the proposition to not conflict with other beliefs to be true in regard to the Coherence Theory. In respect to the Coherence Theory Truth is defined through the relation between beliefs, while the Correspondence Theory explains Truth as relation between an objective reality and propositions.

Pragmatic Theory

In the Pragmatic Theory of Truth utility is of very important. If this is taken as highest principle, we encounter following problem: If it is for somebody more usefull to belief something to be true, it can still be false for somebody else.

Deflationism

According to Deflationism truth does not carry any significance. One of the most popular Theory in this Field is the Redundancy Theory:

Redundancy Theory

The core of the Redundancy Theory is the equivalence thesis:

To say "X is true" has the same meaning as X

Therefore the expression "true" is redundant and has no effect on what we want to express, this means there is no property of truth. The mayor critic about this theory is, that the part of the sentence with the truth-predicate can only be eliminated in simple sentences of the structure like above and not for complex sentences.

Pluralism of Truth

This view on the subject states that there are multiple ways for truthbearers to be true. A possible Pluralist approach would be to state, that in certain domains Truth is expressed in a correspondence to reality (as in the Correspondence Theory) while in other domains it is expressed as part of a coherent system of beliefs (see Coherence Theory).

Formal theories

Tarski's Semantic Theory

The truthbearers in Tarski's Theory are sentences.

In a simplified version of his Convention T he states, that a theory of truth for a Language L must imply for each sentence ø of L:

The sentence ø is true if and only if ø.

For example: \'Grass is green\' is true if and only if grass is green.