Presentation: “Causal Conclusions”

Homework

• Analogies– pp. 81-90

• Review:– Exercises (models for exam)• Analogical Reasoning, e.g., ex. 8.4• Causal Argumentation, e.g., 8.3b• Inductive Generalization, e.g., 8.2b

No need to write out argument in argument form.

Identify the (i) sample, (ii) population, and (iii) target characteristic in this generalization.

At a recent Star Wars convention, where more than 3,000 people participated, 50 people under 50 years of age were polled on which they liked better, Star Wars, or Lord of the Rings. 60% said they preferred Star Wars, 20% said they enjoyed both equally, and 20% said they preferred Lord of the Rings. From this survey, we can conclude that more than 50% of all science fiction fans prefer Star Wars to Lord of the Rings.

At a recent Star Wars convention, where more than 3,000 people participated, 50 people under 50 years of age were polled on which they liked better, Star Wars, or Lord of the Rings. 60% said they preferred Star Wars, 20% said they enjoyed both equally, and 20% said they preferred Lord of the Rings. From this survey, we can conclude that more than 50% of science fiction fans prefer Star Wars to Lord of the Rings.

Strong or Weak? (1a) Sample size?(1b) Statistical representation

of different strata?

(2) Interviewer Bias?

(1) Biased Sample?

CAUSAL STATEMENTSConcept of Causation

Causal Statements

How Blackwater Sniper Fire Felled 3 Iraqi GuardsLast Feb. 7, a sniper employed by Blackwater USA, the

private security company, opened fire from the roof of the Iraqi Justice Ministry…. (Three guards were killed.)

An Iraqi police report described the shootings as "an act of terrorism" and said Blackwater "caused the incident." The media network concluded that the guards were killed "without any provocation."

Washington Post, 11/8/2007

Causal Statements

How Blackwater Sniper Fire Felled 3 Iraqi GuardsLast Feb. 7, a sniper employed by Blackwater USA, the

private security company, opened fire from the roof of the Iraqi Justice Ministry…. (Three guards were killed.)

An Iraqi police report described the shootings as "an act of terrorism" and said Blackwater "caused the incident." The media network concluded that the guards were killed "without any provocation."

Washington Post, 11/8/2007(1) Blackwater (A) caused the incident(2) The guards were killed (B) without provocation• The guards suffered some effect, i.e., not the cause.

Active Voice

Passive Voice

THE MEANING OF “TO CAUSE SOMETHING”

Causation

Meaning of Causation

A. Causal Conditions– A Sufficient Condition– A Necessary Condition– Necessary and Sufficient Conditions

B. Partial Causation– Contributing factors

A. Causal Conditions

A. Causal Conditions• The Sufficient Condition– The presence of this condition alone is capable of

bringing about the effect

– Sufficient but not necessary condition

– Examples: • The intense heat caused a third degree burn. • If you run over a nail, your tire will burst.

A. Causal Conditions• The Necessary Condition– The presence of this condition must exist for effect

to occur at all

– Necessary but not sufficient• The presence of a necessary condition does not entail

the causal event will take place

– Examples: • Without oxygen, the fuel cannot be ignited. • If you want to do well on the exam, then you must

study consistently.

• Necessary AND Sufficient Conditions

P <-> Q

• The biconditional – “if and only if” (iff)– A certain condition, itself, is capable of bringing about the

effectand

– Another condition must exist for first condition to occur at all

A. Causal Conditions

A. Causal Conditions

• Examples from the text– (Boyle’s Law)

The volume and pressure of a gas are inversely proportional

• If the volume of the gas decreases, then the pressure increases

AND• If the pressure of the gas increases, then the volume

decreases.

The volume of gas decreases if and only if gas pressure increases, and vice versa.

Sufficient & Necessary

Causal Arguments

1. What are causal statements?

2. Causation: what does this mean?

3. Types of Causal Arguments

4. Critique of Causal Conclusions (Mill’s Methods)– strong causal conclusions– weak causal conclusions

Causal Arguments

• 4 Types

– Causal statements expressed in premises

1. Causal Predictions2. Causal Explanations3. Causal Prescriptions

– Otherwise

4. Causal Conclusions

Each contains a causal generalization as premise

8.3C, p. 66-68

Causal Arguments

• Causal Conclusions– Premises• Data expresses relation between events

– Conclusion• Establishes that relation is causal

MILL’S METHODSCausal Conclusions

Mill’s Methods

1. Method of:1. Agreement2. Difference• Agreement & Difference

3. Concomitant Variation4. Residue

Mill’s Method: Agreement• Agreement (p. 71)– If more than one

instance of some phenomenon has only one common antecedent, it is probable that this one antecedent is the cause or partial cause.

• Structural Features– the effect occurs in a

number of cases

– a variety of possible causal factors are present• Only one antecedent

present in each case

“modified method of agreement” (p. 73)1. A plurality of antecedent causal factors is

present in each case(Partial causal factors)

Mill’s Method: Agreement• Agreement (p. 71)– If two or more instances

of a phenomena E have only one antecedent circumstance in common, then probably that antecedent is the cause or partial cause of E.• E = effect• “argument form” (p. 72)

• Structural Features– the effect occurs in a

number of cases– In each case there are a

variety of possible causal factors• Only one antecedent

causal factor is present in each case

– “modified method of agreement” (p. 73)• A plurality of antecedent

causal factors is present in each case– Partial causal factors

More instances of agreement

the greater the likelihood that this factor is the cause of E.

Mill’s Method: Difference• Difference (p. 73)– If phenomenon E occurs

and then does not occur when the latter circumstance differs only in the absence of one antecedent, then that absent antecedent circumstance is probably the cause or partial cause of E.

• Structural Features– A minimum of two

happenings• E occurs• E does not occur

– In each case there are a variety of possible causal factors• When E does not occur,

one antecedent factor is removed

Mill’s Method: Difference• Difference (p. 73)

– If an instance of a phenomena E and an instance in which E does not occur differ only in the absence of one antecedent circumstance with the instance of E, then that antecedent circumstance is probably the cause or partial cause of E. • See “argument form” on p.

73

• Structural Features– A minimum of two

happenings• E occurs• E does not occur

– In each case there are a variety of possible causal factors• When E does not occur,

one antecedent factor is removed

More instances difference

the greater the likelihood that this factor is the cause of E.

2 of Mill’s Methods

• Agreement– Event (E) occurs

whenever antecedent occurs

• Difference–Absence of event

(E) coincides with absence of causal factor

A causal conclusion is strong to the degree that it is supported by premises with evidence of one or

more of Mill’s methods (p. 79)

Mill’s Methods: Example

• Six people eat dinner in a restaurant. Liz has soup, a hamburger, ice cream, french fries, and mixed vegetables. Tom has salad, soup, fish, mixed vegetables, and ice cream. Andy has salad, a hamburger, french fries, and ice cream. Sue has french fries, a hamburger, and salad. Meg has fish and mixed vegetables. Bill has french fries, a hamburger, and soup. Later, Liz, Tom, and Andy get sick from something they ate, but Sue, Meg, and Bill don’t. What food made the first three diners sick?– Method of Agreement and Difference

Mill’s Methods: Example

• Six people eat dinner in a restaurant. Liz has soup, a hamburger, ice cream, french fries, and mixed vegetables. Tom has salad, soup, fish, mixed vegetables, and ice cream. Andy has salad, a hamburger, french fries, and ice cream. Sue has french fries, a hamburger, and salad. Meg has fish and mixed vegetables. Bill has french fries, a hamburger, and soup. Later, Liz, Tom, and Andy get sick from something they ate, but Sue, Meg, and Bill don’t. What food made the first three diners sick?– Method of Agreement and Difference

Mill’s Methods: Example

• Six people eat dinner in a restaurant. Liz has soup, a hamburger, ice cream, french fries, and mixed vegetables. Tom has salad, soup, fish, mixed vegetables, and ice cream. Andy has salad, a hamburger, french fries, and ice cream. Sue has french fries, a hamburger, and salad. Meg has fish and mixed vegetables. Bill has french fries, a hamburger, and soup. Later, Liz, Tom, and Andy get sick from something they ate, but Sue, Meg, and Bill don’t. What food made the first three diners sick?– Method of Agreement and Difference

AgreementLiz Tom Andy Sue Meg Bill

Fish *FrenchFries

* *

Hamburger * *Ice Cream * * *MixedVegetables

* *

Salad * *Soup * *

AgreementLiz Tom Andy Sue Meg Bill

Fish *FrenchFries

* *

Hamburger * *Ice Cream * * *MixedVegetables

* *

Salad * *Soup * *

DifferenceLiz Tom Andy Sue Meg Bill

Fish * *FrenchFries

* * * *

Hamburger * * * *Ice Cream * * *MixedVegetables

* * *

Salad * * *Soup * * *

Agreement and DifferenceLiz Tom Andy Sue Meg Bill

Fish * *FrenchFries

* * * *

Hamburger * * * *Ice Cream * * *MixedVegetables

* * *

Salad * * *Soup * * *

Mill's Method: Concomitant Variation

• Concomitant Variation– A first discovery: the volume knob

– If variations in phenomenon E coincide with variations in phenomenon P, then it is probable that E and P are causally related. (p. 75)

Mill's Method: Concomitant Variation

• Types of Variance

• Simultaneous(Where antecedent and consequent remains unclear)

versus

• Sequential(Where definite gap exists between antecedent and consequent)

Mill's Method: Concomitant Variation

• In attempting to diagnose Mrs. Thompson’s high blood pressure, a cardiologist noticed a correlation between fluctuations in blood pressure and certain brain waves. As the blood pressure increased, so did the intensity of the brain waves, and as the blood pressure decreased, the intensity of the brain waves decreased. The cardiologist concluded that the two conditions were causally related.

Mill's Method: Concomitant Variation

• In attempting to diagnose Mrs. Thompson’s high blood pressure, a cardiologist noticed a correlation between fluctuations in blood pressure and certain brain waves. As the blood pressure increased, so did the intensity of the brain waves, and as the blood pressure decreased, the intensity of the brain waves decreased. The cardiologist concluded that the two conditions were causally related.

Mill’s Methods: Residue

Characteristic features1. Deals with complex phenomena

2. Established knowledge of some causal factorsa) in measured quantities

Subtract from any phenomenon such part as is known by previous inductions to be the effect of certain antecedents, and the residue (i.e., remaining parts) of the phenomenon is the effect of the remaining antecedents

Mill’s Method: Residue

• After realizing a loss of $100,000 a department store’s chief accountant could suggest only three causes: an excessive number of clerks, increases in utility rates, and damage to merchandise caused by a flood. These expenses were estimated at $25,000, $30,000 and $10,000 respectively. Since no other ordinary sources could be found, the accountant attributed the remaining $35,000 to shoplifting.

Mill's Method: Residue

• After realizing a loss of $100,000 a department store’s chief accountant could suggest only three causes: an excessive number of clerks, increases in utility rates, and damage to merchandise caused by a flood. These expenses were estimated at $25,000, $30,000 and $10,000 respectively. Since no other ordinary sources could be found, the accountant attributed the remaining $35,000 to shoplifting.

Mill’s Methods

1. Agreement

2. Difference– (Agreement & Difference)

3. Concomitant Variation

4. Residue

Mill’s Methods

1. Agreement

2. Difference– (Agreement & Difference)

3. Concomitant Variation

4. Residue

Typically establishes sufficient conditions

Establishes variable relations

Establishes partial causation

A causal conclusion is strong to the degree that it is supported by premises with evidence of one or more

of Mill’s methods (p. 79)

Homework

• Analogies– pp. 81-90

• Review:– Exercises (models for exam)• Analogical Reasoning, e.g., ex. 8.4• Causal Argumentation, e.g., 8.3b• Inductive Generalization, e.g., 8.2b