Crash Course Philosophy: The Rational Animal and Arguments

Introduction

• Sponsor: Squarespace
• Aristotle's view: Humans as the "rational animal"
  • Rationality as distinguishing characteristic
  • People can be persuaded by arguments

What is an Argument?

• Everyday use vs. philosophical use
  • Everyday: Convincing parents, friends
  • Philosophical: Structured reasoning
• Problems with arguments
  • Misunderstanding argument structure
  • Importance of logic

Plato's Tripartite Soul

• Three Parts of the Soul
  • Rational (logical) part: Seeks truth, swayed by facts and arguments
  • Spirited part: Emotional, fuels actions, driven by honor, duty
  • Appetitive part: Drives physical desires, shared with animals
• Best humans ruled by the rational part
  • Keeps other parts in check
  • Rejected: Some humans less human than others
• Modern understanding
  • Motivated by physical desires, emotional impulses, rational arguments
  • Reason should guide

Testing Reasoning

• Bertrand Russell's Barber Paradox
  • Town with men required to be clean-shaven
  • Barber shaves all men who don't shave themselves
  • Barber does not shave men who shave themselves
  • Paradox: Does the barber shave himself?
  • Illustrates logical impossibility

Structure of an Argument

• Premises and Conclusions
  • Premises: Evidence for the belief
  • Conclusion: What you believe
• Deductive Arguments
  • If premises are true, the conclusion must be true
  • Example:
    • Premise 1: All humans are mortal
    • Premise 2: Socrates is human
    • Conclusion: Socrates is mortal
  • Entailment: One fact leads to another
  • Validity: Truth of premises guarantees truth of conclusion
• Valid vs. True
  • Valid argument can have false conclusions if premises are false
  • Example: Incorrect premises about human traits

Sound Arguments

• Deductively sound argument: Valid with true premises
  • Guarantees true conclusion
• Importance of deduction
  • Provides certainty
  • Limited by known, true premises
  • Often leads to obvious truths

Next Steps

• Need other types of arguments for unknown premises
• Future exploration of other argument types

Conclusion

• Value of reason and structured arguments
• Focus on deductive reasoning in this lecture

Credits

• Sponsored by Squarespace
• Produced with PBS Digital Studios
• Filmed in Doctor Cheryl C. Kinney Crash Course Studio
• Graphics by Thought Cafe