Deduction and Induction
Philosophy with Professor Parsons・2 minutes read
Deductive arguments guarantee the truth of the conclusion based on true premises, while inductive arguments aim to show the conclusion is more likely than not true. Valid deductive arguments ensure true premises lead to a true conclusion, while strength and cogency in inductive arguments assess the likelihood of the conclusion being true based on the premises.
Insights
- Deductive arguments aim to guarantee the truth of the conclusion based on true premises, while inductive arguments aim to show the conclusion is more likely than not true based on true premises.
- Validity in deductive arguments is determined by the logical structure of the argument, ensuring a true conclusion from true premises, while inductive arguments focus on the strength of premises impacting the likelihood of the conclusion being true, with terms like strength and cogency used for assessment.
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Recent questions
What is the purpose of deductive arguments?
To guarantee the truth of the conclusion.
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Summary
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Types and purposes of logical arguments
- Deductive arguments, inductive arguments, and abductive reasoning are distinct types of arguments with different purposes.
- Deductive arguments aim to guarantee the truth of the conclusion based on true premises, providing logically conclusive support.
- Inductive arguments, on the other hand, aim to show that the conclusion is more likely than not true based on true premises, without guaranteeing its truth.
- Classical validity in deductive arguments ensures that true premises guarantee a true conclusion, while invalidity indicates the possibility of a false conclusion from true premises.
- The distinction between validity and invalidity in deductive arguments is solely based on the form or pattern of the argument, not the actual content or truth of the premises.
- Counterexamples can be used to demonstrate the invalidity of an argument pattern by replacing variables with new terms to show true premises leading to a false conclusion.
- Valid deductive arguments can be classified as valid and sound (guaranteeing a true conclusion with all true premises), valid and unsound (guaranteeing a true conclusion with at least one false premise), or invalid and unsound (not guaranteeing a true conclusion).
- In inductive arguments, the terms strength and cogency are used instead of validity and soundness to assess the likelihood of the conclusion being true based on the premises.
- Modus ponens is a common valid deductive pattern that uses conditional statements to guarantee the truth of the conclusion when the premises are true.
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Validity and Strength in Inductive Arguments
- Modus tollens is a common pattern of argument where if P is true, then Q is true; if Q is false, then P is false. It is a classically valid pattern of argument, ensuring the truth of the conclusion when the premises are true.
- Inductive arguments can be strong or weak, cogent or uncogent. A strong inductive argument means the conclusion is more likely with true premises, while a weak argument does not make the conclusion more likely. The truth of premises must impact the conclusion for the argument to be strong.
- In inductive arguments, strength is determined by the premises actually increasing the likelihood of the conclusion being true. A strong and cogent inductive argument indicates the conclusion is more likely with true premises, while a weak and uncogent argument does not make the conclusion more likely, regardless of the truth of the premises.
