Critical Thinking Lecture 12 Causal Arguments

1. Critical ThinkingLecture 12Causal Arguments By David Kelsey

2. Causal Arguments • Causal claim: states or suggests the presence of causation. • Examples: • A causal argument has as its conclusion a causal claim. • A cause is an event, person, place or thing X without which some other event, person, place or thing Y, X’s effect, would not occur, exist, etc. • A cause necessitates its effect such that without the cause, the effect would not occur. • Causes can’t just be correlations though. • Causal powers

3. Post Hoc Fallacy • Post Hoc Fallacy: When one thinks that just because X is followed by Y this must mean that X causes Y. • Post Hoc is short for Post Hoc, Ergo Propter Hoc which translates: • The mistake is Thinking Correlation entails causation: • Accidental correlation: this is a mistake because X could play no role in Y’s coming to be. • X could merely be accidentally correlated with the occurrence of Y. • 3 pennies example: • Other possibilities besides X causing Y or X and Y being accidentally correlated:

4. Hypotheses • Hypothesis: a supposition offered as a starting point for further investigation. • When hypothesizing you are conjecturing, I.e. making a guess about some way the world is. • How do we test a hypothesis? • Look for counterexamples to it. • What is a Counterexample? • A counterexample to: Vitamin C cures colds

5. Relevant difference reasoning • Relevant difference reasoning: • If some effect, Y, occurs in one situation & Y doesn’t occur in other situations similar • we can try to find something that is different about this situation, I.e. X. • We then suspect this difference X is the cause of Y. • To find X, simply look for the differences between this situation and those situations that are similar but in which Y doesn’t occur. • Use relevant difference reasoning when:

6. Which difference is relevant? • Question: how do you know which is the relevant difference? • Engine overheating:

7. Examples of Relevant difference reasoning • Examples of relevant difference reasoning: • Headaches: • Post Office:

8. Common Thread Reasoning • When do we use this kind of reasoning? • Look for a common thread: some event, person, place or thing that is common to all the occurrences of the effect. • Mosquito example:

9. Common mistakesin informal causal reasoning • 1.) We can overlook alternative common threads or differences: • If one difference or thread seems particularly relevant, don’t overlook others as you may miss the real cause in doing so. • Example: • 2.) We can focus on irrelevant differences or common threads: • To know that a difference or thread is relevant you must have some knowledge of the situation, its causes and its effects.

10. 3 more mistakes • 3.) We can overlook the possibility that causation is the reverse of what has been asserted: • Climbing a rope: • 4.) We can overlook the possibility that the asserted cause and effect are both the effects of some third underlying cause: • The leaves turning yellow: • 5.) We can fail to consider the possibility of coincidence: • The cancer example:

11. Doubtful causal claims • 1. Appeal to Anecdotal evidence: watch out for a causal claim when the evidence is one or two cases only. • Smoking doesn’t cause cancer: • To show smoking doesn’t cause cancer we need to show that even if everyone smoked, the cancer rate would not increase. Can you do this with 1 piece of evidence though? • 2. Circularity: The cause cannot merely restate the effect for if so we haven’t learned anything new. • Insomnia example: • 3. Excessive Vagueness: if a causal claim is too vague we won’t know exactly how it is to be tested. • Bad Karma example:

12. Doubtful causalclaims #2 • 4. Nontestability: we can’t have a causal claim for which testing is isn’t possible. • Aids example: • 5. Unnecessary assumptions: why needn’t make any unnecessary assumptions in asserting a causal claim? • Déjà vu example: • 6. Conflict with well-established theory: as a general rule, we don’t really want our causal claims to conflict with our theories. • We can have theoretical advances, but… • Height example:

13. Causal Explanationsvs.Arguments • A causal explanation is an explanation of the cause of something. • Explanations vs. Arguments: while causal explanations can look superficially like arguments, explanations assert cause and effect while arguments try to prove that something is the case. • Explaining causes: When we try to justify or defend or excuse something we or someone else did, we sometimes explain its causes. • Bread example: • But not every attempt to explain behavior is an attempt to excuse it: One might be simply trying to offer an explanation without any sympathy at all for the actions being explained. • Nazi Germany example: