3．Popularization of Philosophy: A View of Truth of Coherence Theory

In daily conversations, people rely on the truth predicate. For example,this apple is really here, the weather forecast is true, and her story is not true. However, in what sense do we talk about “truth”, and what “truth”means in language is rarely thoroughly reflected. In the philosophical tradition, three theories give different answers: correspondence theory,coherence theory and pragmatism theory. This paper introduces and refutes the truth view of correspondence theory, and introduces a truth view of coherence theory without reference.

According to the correspondence theory of truth, the fact that something is true means that we can find the fact correspondence in the real world. For example, the proposition “It's raining in Beijing now”is true and only true if it's actually raining in Beijing in reality. “It's raining in Beijing” is the meaning of this proposition, while the fact that it is raining cats and dogs outside the window is the reference of this proposition. Finally, the fact that “it is really raining now” is the realization of the reference in reality. The correspondence theory of truth accords with people's intuition, and therefore it has been widely accepted in history. Frege, a famous philosopher, also confirmed this idea in Sense and Reference : therefore, we have to accept the reference of a proposition as the truth value of the proposition. In other words, a proposition being true means that reference, meaning and truth value have established an equal relationship. On the contrary, if the fact described by the proposition does not happen in reality, it means that the true value has not been realized and the proposition is false. For example, the proposition that “the 21st president of the United States is Polly Pony” is meaningful, but in reality, it can't find the facts to correspond to it, so it is false.

As early as the 17th—18th century, Leibniz realized that this seemingly obvious relationship contained a problem: reference. Frege himself pointed out that according to the traditional correspondence theory, if a proposition is true, it means that the meaning of the proposition corresponds to a specific fact (that is, reference), and this fact does exist in reality (the truth value is 1). Then, if two propositions correspond to the same reference, they are semantically equal.

(P1) Lu Xun is a famous writer who wrote Call to Arms .

(P2) Lu Xun is Zhou Zhangshou.

(P3) Lu Xun was born on September 25th, 1881.

P1, P2 and P3 all describe the object of Lu Xun and are true propositions, so they have the same reference. The problem is that P1 is obviously a description of Lu Xun's works, P2 is a description of Lu Xun's name, and P3 is a description of Lu Xun from the perspective of his birth year. Although these three propositions have the same reference and correspond to real events, they obviously have very different semantics.According to the traditional correspondence theory, people will be forced to accept the absurd relationship that “1+1=2” equals “grass is green”.Davidson concluded, “Nothing makes a sentence come true.”

Furthermore, Wittgenstein retorted, “In Frege's theory, the reference to fix a given proposition itself presupposes an explanation of meaning, and this explanation itself is used before the proposition.” In other words,if the understanding of meaning is not established in advance, people can't determine the reference at all, let alone know what the conditions for realizing the truth value are.

All kinds of objections show that the concept of reference in the traditional truth theory is full of problems, and Wittgenstein and Quine's work have pointed out that understanding “what is meaning” is very important for understanding “what is truth” . Abandoning the traditional correspondence theory based on reference makes the theory of truth leap forward.

Davidson put forward the coherence theory of truth. Davidson's view of truth is based on the Tarski Convention, that is, “P” is true if and only if P. The former is a proposition, while the latter is the meaning of the proposition. For example, “apples are red” is true if and only if apples are red. The advantage of Tarski Convention is that it successfully establishes the truth that does not depend on reference or experience by means of recursive definition. For example, in the Tarski Convention, as long as one understands the meaning of“apples are red” , then this equation can be easily established.

Different from the traditional Tarski Convention, Davidson's revised version is “P” is true if P in L. In Davidson's theory, “P” can be a proposition in any language, and P is the translation of this proposition in another meta-language. Through translation, P also determines the meaning of “P”(Meaning “It's raining here”iu German). For example,“Es regnet”(Meaning “It's raining here”iu German) is true if and only if it's raining here. “It's raining here” is a translation of the proposition “Es regnet” , and it also explains the meaning of the proposition. The process of translation is called radical translation. Davidson emphasized that the establishment of this meaning theory does not need any referential concept in practice, but is accomplished by a lexicographical method.

In Davidson's teacher Quinn's famous “Gavagai” example, Quinn proposed an interesting scenario. In an indigenous language, “Gavagai”can represent both rabbit and rabbit hunting. When a lexicographer doesn't understand the exact meaning of the word, what can he do to establish the relationship between English and the indigenous language? Quinn believes that through the comparison of behaviors, that is, the method of lexicography, people can establish mutual translation between languages without presupposing meaning and reference in advance. For example,a lexicographer can grab a rabbit and shout “Gavagai” and observe the indigenous translation. When such vocabulary is established enough, a lexicographer can understand the meaning of “Gavagai” and even further grasp the indigenous language itself.

Davidson borrowed Quinn's behaviorism and lexicography methods and further pointed out that the translation between Gavagai and rabbits depends on the premise that the lexicographer's world system and the indigenous world system are the same. If two people have diametrically opposite and fundamentally irreconcilable cognitive systems, then obviously the lexicographer can't successfully complete the translation of the indigenous language. Therefore, with every suggestion of Tarski Convention, the speaker and the receiver will establish a whole knowledge system. The understanding of each proposition in this system depends on the existence of other propositions. For example, the reason why “the sun rises in the east and sets in the west” can be understood lies in the concept of “the sun”, and the concept of “the sun” depends on the pre establishment of concepts such as “the universe”. In other words, the set of all meanings constitutes the world, and the establishment of this set has already established “truth” in Davidson's view. This is the Davidsonian coherenism.

Admittedly, some people may challenge that not all beliefs are true in this system. For example, a person may be deceived by an evil demon into thinking that the sun rises in the west. Or a person may be a skeptic who thinks the world doesn't exist. In short, this person is a philosopher.Davidsonian coherenism is an inclusive theory, and its establishment allows the above situation to exist. However, in Davidson's view, with the increase of dialog and propositions in the set established by radical explanations, the wrong propositions will be challenged by mutually exclusive propositions.These challenges will increase the number of true propositions. In other words, the establishment of truth is an organic and dynamic process. People don't need to confirm that all truths can be established immediately, but only that this process is feasible. To the objection of skepticism, Davidson responded that all incompatibilities only occur when the theory of meaning and experience are in opposition. But Davidson's own theory just doesn't need the existence of experience, it is just a theory about meaning. The established method is not to return to reality and correspond to the facts like the correspondence theory, but to directly establish the meaning of expression through radical translation.

Understanding Davidson's view of truth is of great value in the philosophical sense, which can effectively make people break away from the dogma of traditional correspondence theory and avoid all kinds of challenges against the concept of“reference”.