Definition

The study of the origin, nature, and limits of human knowledge. It asks: How do we know what we know?

Definition

The study of correct reasoning and the principles that lead us to truth. Logic provides laws that cannot be violated if truth is to be maintained.

Definition

A self-evident assumption or belief accepted as true, though not provable. Example: Two parallel lines never meet.

Definition

Foundational beliefs or postulates that shape how we interpret reality. Example: An atheist presupposes “There is no God.”

Definition

A truth so obvious that it requires no proof. Example: I exist.

An argument that begins with axioms and leads to conclusions that must be true if the premises are true. Example:

• All men are mortal.

• Socrates is a man.

• Therefore, Socrates is mortal.
  
  

Reasoning from specific observations to general conclusions. The conclusion is probable, not certain. Example:

• All observed swans are white.

• Therefore, all swans are white. (until a black swan is seen).

Reasoning that infers the best explanation by showing alternatives lead to absurdity.

A thing is identical to itself. A = A.

Two contradictory propositions cannot both be true in the same sense at the same time.

Every proposition must be either true or false; there is no middle ground.

A flaw in reasoning.

• Formal Fallacy: Error in logical structure.

• Informal Fallacy: Error in content or faulty assumptions.

Using a word in two different senses to confuse an argument. Example: “evolution” (micro vs. macro).

One where the conclusion follows logically from the premises (though the premises may be false).

One that is both valid and has true premises, leading to a true conclusion.

The belief that truth and morality are relative to individuals or cultures, denying objective truth.