Introduction

• In court, witnesses swear to tell the truth, the whole truth, and nothing but the truth, assuming a shared understanding of truth.

• The concept of truth is abstract, ambiguous, and mysterious, especially as discussed by philosophers.

• Philosophers focus on the meaning of truth as what a witness assumes: reporting what one believes to be true in statements or propositions.

• Voltaire suggests that we can define truth humanly but must remain open to better definitions since there is no final or definitive definition of truth for all times.

• Defining truth is difficult because:

  • It is an extremely basic concept used in all theoretical inquiry; questioning truth itself requires using the concept of truth.

  • We cannot get behind or beyond the concept of truth, unlike other concepts.

  • Truth is deeply connected to belief; witnesses report what they believe to be true.

  • Truth relates to knowledge; knowing something requires it to be true (e.g., knowing a person committed a crime means they actually did).

  • Truth is a central concept in logic.

  • Truth is related to reality; to speak the truth means to describe reality as it is.

• Truth is interconnected with many concepts, and understanding these connections is important to understand what truth is.

• Knowledge is the recognition of truth.

• Mistaking falsity for truth results in false knowledge; believing a false statement to be true is a mistaken belief.

• If knowledge excludes all falsity, then certainty becomes essential for knowledge.

• If certainty is unattainable, it follows that truth and knowledge are also unattainable.

• Some philosophers adopt a very rigorous conception of knowledge, limiting what can be claimed as known.

• Denying the existence of truth neglects everything valuable, since what is good and beautiful depends on truths about them.

• We should admit that absolute certainty or absolute truth is unattainable.

• Even scientific findings are not considered final or definitive.

• We must continue the search for truth and be ready to abandon prevailing beliefs when proved false.

• We must learn to doubt and believe again, or to believe without believing absolutely.

• Skepticism is the claim that none of our beliefs is objectively justified as more probably true than its negation.

• Skeptics hold that the search for truth is hopeless and that every opinion is as good as another.

• Skepticism expresses the concern that our beliefs may not accurately correspond to reality (the world in itself).

• A certain degree of doubt is natural and motivates the search for truth.

• In daily life, people are generally more believers than doubters; for example, we trust doctors to cure us and pilots to fly planes.

Nature and Criteria of Truth

• Theories of truth aim to answer: “What is truth?” and “How to know the truth?”

• The focus is on determining whether propositions or beliefs are true or false.

• To address propositional truth, there are two approaches:

  • The definitional route, which defines “is true” as a qualifier of a proposition.

  • The criterial route, which justifies when to apply “is true” to a proposition.

• The question of the nature of truth is similar to asking about the nature of gold or the meaning of the word “gold” in ordinary language.

• For gold, empirical inquiry shows it is an element with atomic number 79 and many substantive facts (e.g., malleable yellow metal).

• When philosophers ask about truth, they may focus on:

  • The concept of truth,

  • The underlying nature of the property of truth, or

  • Both.

• Unlike gold, there is no independent empirical access to the property of truth except through the concept of truth.

• Therefore, disputes about truth often occur on conceptual grounds, debating how best to define the concept of truth.

• Learning about the concept of truth may reveal much about the property of truth but not necessarily all aspects of it.

• Knowing the nature and being able to define truth is insufficient unless we can also prove something is true.

• The nature of truth and the criteria for truth are different.

• The definition of gold as a yellow metal with atomic number 79 does not help us determine if an ornament is actually gold.

• The criteria (such as the assayer’s test with aqua regia) help verify gold, but do not define it.

• This distinction applies to truth as well: knowing the meaning of “true” is only half the task; we must also apply it.

• If we adopt the criterial route, critics argue that we only address what is taken as true, not the core issue of what truth really is.

• Conversely, if we adopt the definitional route, critics claim the definition is only formal and does not help determine whether a proposition is actually true or false.