Philosophy of Being and Knowledge

Epistemology (Philosophy of Knowledge)

Truth

If knowledge is defined as justified true belief, then delineating the concept of knowledge necessitates an examination of truth as a requisite condition of knowledge. The philosophical tradition has offered one principal response to the question of what truth is, with its definitive formulation provided by Thomas Aquinas (1225-1274). This formulation posits that truth is the correspondence between a thing and the mind (Veritas est adaequatio rei et intellectus). This definition is known as the correspondence theory of truth. According to this definition, something is true if it corresponds to its prototype. For instance, the statement "A car has four wheels" is true if and only if the car indeed has four wheels; if the car has three or five wheels, the statement is false. The correspondence theory implies a dual interpretation of truth: if truth is the correspondence between a thing and the mind, then the question arises whether it refers to the relationship of the thing to the mind or the mind to the thing:

• Logical truth pertains to the truth of statements, i.e., the correspondence of the mind to the thing. Only statements can possess logical truth; thus, only statements can be logically true or false. For example, when someone asserts "The car has four wheels," they are either telling the truth or lying. Questions, exclamations, and individual words cannot be true or false as they do not assert anything through their medium;
• Ontological truth refers to the truth of a thing, i.e., the correspondence of the thing to the mind. Any thing is created according to some plan or project. If the final result of creating the thing aligns with its project, then the thing is true; if it does not match the design, it is false. Expressions such as "true friend," "true teacher," and "true wonder" indicate that the entities in question correspond to their intended design.

Thus, truth is the correspondence between a thing and the mind. Although this definition is widely accepted, it requires further clarification to be practically useful. The correspondence theory of truth explains what truth is but does not elucidate how to verify it. For instance, if someone claims "a viper bite is deadly," the correspondence theory implies that the statement is true if a viper bite is indeed deadly, but it does not explain how to establish the truth or falsity of this statement. Various philosophical schools have proposed different methods for resolving this dilemma, which have come to be known as theories of truth. None of these proposed criteria have conclusively resolved the issue, and each has faced significant critique.

• Coherence Theory of Truth: According to this theory, a statement can only be considered true if it fits within the overall worldview and does not contradict other theories accepted in the relevant domain. For example, if someone proposes a hypothesis in physics, that hypothesis can be deemed true if it is coherent with all other accepted theories in physics. Many philosophers from the modern era to the present have adhered to this criterion of truth, with English philosopher Harold Henry Joachim (1868-1938) offering a contemporary formulation.

✵ Critique of the Coherence Theory: Most critics argue that historical scientific paradigms included false theories, with scientists rejecting true statements simply because they did not align with the prevailing paradigm. For example, geocentrism was a false theory, but during its dominance in astronomy, any scientist presenting ideas inconsistent with geocentrism was condemned by the scientific community.

• Consensus Theory of Truth: This theory has been most vigorously defended by German philosophers Jürgen Habermas (b. 1929), Karl-Otto Apel (1922-2017), and Paul Lorenzen (1915-1994). They argued that a statement should be considered true if it achieves consensus among experts. For instance, if someone proposes a hypothesis in physics, it should be considered true if leading physicists agree with it. In contemporary science, the consensus theory has become dominant. To earn a scientific degree, a researcher must present their findings in a dissertation, defend it, and obtain the degree only when leading scientists agree. In complex medical cases, diagnoses are decided by a medical panel. Articles are published in scientific journals only after reviewers evaluate them as scientific.

✵ Critique of the Consensus Theory: The history of science reveals that no revolutionary scientific theory has been smoothly accepted by the scientific community. Every scientist proposing innovative ideas has faced exclusion or persecution. Gaining the approval of experts requires significant time and effort from those presenting novel ideas.

• Pragmatic Theory of Truth: Pragmatism is one of the most popular philosophical schools of the 19th and 20th centuries. Its main thinkers include Americans Charles Sanders Peirce (1839-1914), William James (1842-1910), John Dewey (1859-1952), and others. Pragmatism values what proves practically useful. In the debate about truth, pragmatists argued that a statement should be considered true if its use is beneficial. For example, if people accept the statement "A viper bite is poisonous" as true and it helps save lives from deadly risks, it should be considered true.

✵ Critique of the Pragmatic Theory: Truth and practical usefulness do not always align. This theory can even justify unethical actions. For instance, corruption may provide financial gain to an official, but that does not mean corruption should be justified.