Lecture on Logic and Argumentation

Key Concepts

• Data Collection in Science: Observation, experiments, archival studies.
• Objective of Scientists: Draw conclusions from data, prove/disprove theories.
• Importance of Argumentation: Differentiates between valid conclusions (good arguments) and invalid conclusions (bad arguments).

Terminology

Argument Structure

• Premises: Assumptions or presupposed statements.
• Conclusion: What is inferred from the premises.

Example

• Premise 1: No medieval king had absolute power over his subjects.
• Premise 2: Louis VII of France was a medieval king.
• Conclusion: Louis VII of France did not have absolute power over his subjects.

Valid vs Invalid Arguments

• Valid Argument: Conclusion logically follows from premises.
  • Example: Louis VII argument.
• Invalid Argument: Conclusion does not logically follow from premises.
  • Example: Premise about Louis VII being a great horseman leading to conclusion about power.

Validity and Truth

• Validity is independent of the truth of premises or conclusions.
• Possible Combinations:
  • Valid argument with false premises.
  • Invalid argument with true premises.

Types of Arguments

Deductive Arguments

• Definition: Truth of premises guarantees truth of conclusion.
• Characteristics:
  • No new falsehoods introduced if premises are true.
  • Validity determined by form, not content.
• Example (Form): "No A is B, C is A, so C is not B".
  • Can be applied to different contexts (e.g., Dutchman being humble).

Inductive Arguments

• Definition: Truth of premises makes conclusion likely but not certain.
• Characteristics:
  • Premises provide good reason to believe conclusion.
  • Generally used in science.
• Example: Studying medieval texts to infer scholars' arguments about existence of God.

Science and Arguments

• Scientific Method: Not purely deductive; relies heavily on inductive reasoning.
• Next Lecture Preview: Challenges of induction in scientific reasoning.