Causal Reasoning

Husein Inusah (PhD)

Adjunct Lecturer in Philosophy
University of Ghana
 Different senses of “cause”
• Immediate cause of something, even if that
thing has more remote and foundational
causes.
• Example:
• Samson decided to become an armed robber.
It put him in a situation where he engaged in a
shootout with the police, and the police killed
him.
 Contributory cause
• A cause among many other causes.
• Example:
• A distressed economy contributed to Samson’s
decision to become an armed robber, and
hence to end up being killed by the police.
 Necessary cause
• Or cause as necessary condition.
• When something is a necessary condition for
another thing. Without it, the other will not
exist.
• Example:
• Without oxygen life is impossible.
 Sufficient cause
• Or cause as sufficient condition.
• Something could be a sufficient condition for an
effect if the presence of that thing is adequate
for the presence of the effect. One does not
need to express doubt at seeing the effect
when she sees the condition
• Example:
• To be prevented from inhaling oxygen for
twenty minutes is sufficient condition for death.
 Another example of sufficient cause

• Proving that a healthy and sane person

calculatedly committed a murder is an
adequate condition for sentencing the person
to life imprisonment if this is the appropriate
sentencing for such a crime in that
jurisdiction.
 Individually necessary and jointly sufficient
conditions
• We can say that there are several individually
necessary conditions for effect, and that a
combination of these conditions becomes
sufficient for the effect.
• In life and in science, it is usually difficult to
determine what number of causes are jointly
sufficient for an effect to occur.
 Example
• Oxygen, water, food, and health are
independently necessary conditions for a
human being to stay alive.
• But they (and some other factors we may not
know yet) are sufficient for staying alive.
 Probabilistic Cause
• This is the opposite of necessary cause.
• This kind of cause is theoretically not
necessary (not a must) for the effect.
• Example:
• A crisis-ridden economy, the lack of a job, and
the need to marry and settle down are
probable causes of Samson’s decision to
become an armed robber.
 Causal agent as cause
• A causal agent is also a cause.
• Example:
• Clement is the cause of the crisis.
 Causal chain and causal web
• Causal chain: so many causes, each one
leading to another.
• Causal web: when the relationship between
causes is more like a web than a chain.
• Two contributory causes could occur
simultaneously.
 Example of causal web
• It could be that the police officer who killed
Samson did so because he (the officer) aimed
his gun correctly whilst his colleagues did not,
and at the same time Samson got killed
because he squeezed his trigger to kill the
police person before the police killed him, but
found that there were no more bullets in the
firing chamber of his gun.
Informal Causal Reasoning Patterns
• Causal reasoning – a type of inductive argument
attempting to establish the causal relationship between
phenomena or events.
• A causal claim indicates that something causes another.
• A causal hypothesis is an initial speculation made in
relation to a causal claim, a supposition offered as a
starting point for further investigation.
• To study two things: first the various informal causal
reasoning strategies for arriving at causal claims.
• And the various experimental strategies for confirming
causal hypotheses.
 Mill’s 3 methods
• John Stuart Mill in his book titled, A System of
Logic (1893) - 5 approaches for detecting
causation by observation.
• We shall study 3:
• The relevant difference reasoning (the method of
difference)
• The common thread reasoning (The method of
agreement)
• Method Concomitant Variation
 Relevant difference reasoning
• Method of reasoning that identifies something
that occurred differently from others as the
cause of an effect.
• A is the difference among others. So A caused
the effect.
 Example
• I have always taken tea and bread for my breakfast, but on a
certain day last month I fell sick shortly after my breakfast. I
treated the illness and fell sick again last week after my
breakfast.
• I ask myself why I have fallen sick on these two occasions after
breakfast, and it occurs to me that on these occasions I had
taken marmalade with the breakfast.
• I check the information provided on the marmalade container –
the marmalade has expired long ago.
• I suspect that this is the reason why I have fallen sick twice.
• Since I have always taken tea and bread without health
implications, the expired marmalade becomes the relevant
difference in explaining the possible cause of the two illnesses.
 Common thread reasoning
• Method of reasoning that identifies something
that occurred in all the instances that have led
to a particular effect.
• A is the common thread among all the events.
So A is the cause.
 Example
• When I bought the marmalade some months ago, I
had gone shopping in the company of my neighbours,
and we had all bought the same stock of marmalade
(which expired at the same time).
• Assume my neighbours are equally sick - they also
traced the cause of their illnesses to the expired
marmalades.
• It means we have all identified the expired marmalade
as the common thread in all the cases of this
particular illness in the neighbourhood.
 Concomitant variation
• Method of identifying the degree of occurrence
of something, rather than its simple presence or
absence
• Used when we cannot eliminate a particular
cause from the environment (example, carbon
dioxide).
• Useless to use relevant difference to identify
carbon dioxide as cause of ill health.
• Use a method that measures its degree or
intensity.
 Example
• It was revealed through research that high blood
pressure (HBP) is exacerbated in regions whose soils
have low levels of selenium.
• This is a metal that exists in tiny quantities in every
soil, and because of this, we cannot measure for its
absence or presence.
• We can only account for the effects of varying
degrees of it, and hence the discovery that it seems
correlative with the ability of our bodies to keep our
blood pressure normal.
 Second example
• It was discovered that high levels of sulphur dioxide
pollution in the air was responsible for high rates of
deaths in London between November and December
1952.
• There is no way to eliminate sulphur dioxide from
the air.
• The experiment discovered the causal connection by
comparing the increase and decrease of the effect
(number of deaths per day) to the daily variation in
degrees of sulphur dioxide fumes in the air.
 Causal fallacies
• Or fallacies of causal reasoning.
• Or bad causal reasoning.
• These fallacies are committed when the link
between an alleged cause and effect depends
on a causal link that does not exist.
 Post hoc ergo propter hoc
• Or fallacy of inferring causality from
chronology
• Example:
• For the first time today I took beans for
breakfast. And I performed wonderfully in my
mathematics test. Therefore a breakfast of
beans is very crucial to mathematical
proficiency.
 Non causa pro causa/Confusing cause with
effect
• Or fallacy of exchanging or confusing cause for
effect.
• Example:
• Michael is a poor student because he performs
poorly in examinations.

• Correct the fallacy:

• Michael performs poorly in examinations
because he is a poor student.
 Oversimplified cause
• Occurs when there are many causes, and the
argument identifies only one of them as the
cause.
• Example:
• The Cameroonian team won the trophy
because their coach is paid a higher salary.
 False common thread
• When we infer a common thread as a cause
when it is not.
• Example:
• All the academically bright guys in my class
have cars. So I will get a car as part of my
desire to be academically bright.
 Confusing correlation with causation
• Just because two things often occur together
does not mean there is a direct causal
relationship between them.
• Example:
• Each time a car moves, we see smoke coming
from the exhaust tube. Therefore the smoke
causes the car to move.
• Correction: The smoke is not what causes the car
to move. Both the movement and the smoke are
caused by the engine combustion.
 Slippery slope
• When we suggest that a relatively insignificant
event will cause a more significant event, which
in turn will cause an even more significant event,
and the order of significance continues to
increase, without adequate justification as to
why each significant event will lead to a more
significant event.
• A progressively dubious chain of premises
(usually consequences) is often employed to
support a conclusion or claim.
 Another explanation
• Fallacy of arguing that if A is allowed, it will
trigger a set of events that eventually lead to
Z, and it is only a matter of time to go from A
to Z (to slip down a slippery slope from A to Z).
• This should not be a fallacy if the causal
movement from A to Z is justified.
• It is a fallacy if the causal movement is not
justified or justifiable, which means that it is
fatalism (an extreme version of determinism)
 First example
• If Donald Trump becomes the President,
America will fight many wars
• – Democrats.
 Second example
• It is wrong to believe in God because then you would
eventually believe in not just God but all kinds of spirits,
• and then come to believe that spirits have all kinds of
power (superstition),
• and then come to believe that inanimate objects have
spirits (animism),
• and then come to believe that everything has spirits
and power to do something or the other, thereby
ultimately destroying your ability to evaluate cause and
effect in natural terms.
 Third example
• I cannot allow my child to go outdoors and play in the
compound. This is because if I do, she will jump fence and
go into the streets.
• If she goes into the streets, she will run away with any
stranger.
• If she runs away with any stranger, then I will never see her
again.
• If I never see her again, I will be miserable for the rest of
my life.
• If I am miserable for the rest of my life, I will commit
suicide.
• So for the purpose of the avoidance of suicide, I will not
allow my child to play outdoors in my compound.