1. Critical Thinking Lecture 12 Causal 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
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
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 mistakes in 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 causal claims #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 Explanations vs. 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: