Unit 8 Causality

Learning outcomes

By the end of this unit you should:

  • understand 9 types of causes
  • be able to evaluate causality chains and networks
  • have practiced indentifying assumptions
  • understand the Rashomon effect


Activity 1 Reading

Read this.

One action (A1) may cause another action (A2). For example, a punch hitting a nose (P1) can cause the nose to bleed (B2)! This can be represented as:

[1] P1 → B

In this example, the first action P1 is the cause and the second action B is the effect. Causes and effects may occur in series, which each effect becoming the cause for the next in the linear sequence. For example, a punch hitting a nose (P1) can cause the nose to bleed (B2). The blood drops (D3) onto a white T-shirt. The T-shirt gets a red stain (G4).

[2] P1 → B → D3 → G4

In this series P1 is the cause of B which is the cause of D3 which is the cause of G4. In short, there are three causes and three effects. Often the focus is on the final effect and the causes that result in that effect. By convention, we can use C for causes and E for the final effect, and so we can rewrite [2] as:

[3] C1 → C → C3 → E4

As there is more than one cause, we may need to refer to particular causes more precisely. The first cause in a chain of causes is called the root cause. In [3] the root cause is C1. The cause closest or close to the effect is called the proximal cause while a cause considered far from the effect are known as a distal cause. In [3] C1 is both the root cause and a distal cause, C3 is the proximal cause.

Linear causality chains often present a simplistic view of causes as there is only one possible path. A causal network can be drawn to represent multiple paths as shown in Figure 1.

Shared causes (common causes)have two or more paths connected to them (e.g. C1, which is also a root cause). Competing causes (rival causes) are those that occur on different paths (e.g. C2 and C4).

A necessary cause is one that must be present for the effect to occur while a sufficient cause is one that might be present, but is not necessary.

causality network

Figure. 1: Causality network for three related effects

For effect E1 in Figure 1 there is one root cause C1, one proximal cause C3 and based on distance in space, three distal causes (C1, C2 and C4). C1 is a necessary cause, because it is impossible to achieve effect E1 without C1 occuring first. C2, C3 and C4 are sufficient causes, since either the path with C2 or the path with C3 and C4 must be followed to acheive effect E1.

Activity 2 Thinking

For effects E2 and E3, which cause or causes can be classified as:

  1. root causes
  2. distal causes
  3. proximal causes
  4. common causes (shared causes)
  5. rival causes (competing causes)
  6. sufficient causes
  7. necessary causes

Share your views with your partner. If you have any questions or comments, share them in the unit forum on ELMS.

Activity 3 Thinking

Identify the probable or possible causes for the following effects. Use your world knowledge and be aware of your assumptions. The first one serves as an example

  1. There is a rainbow. - The probable cause is that there is light shines on water vapour in the air. The probable cause for the light shining is the presence of the sun in a clear sky. The probable cause for the water vapour is that it has just finished raining.
  2. There is a high tide at the beach.
  3. Protesters are stopping cars in the street.
  4. Visas are necessary to enter North Korea.
  5. Hair loses its colour as people age.
  6. It is difficult for humans to see at night.

Share your views with your partner and/or in the unit forum on ELMS.


Activity 4 Assumptions

Read the explanation below to undersand assumptions, hidden assumptions and overlooked assumptions.

Simply put, assumptions are premises that are not overtly stated. These assumptions may be shared by a community and so there may be no necessity for stating them. However, at times the writers and readers of arguments may have different assumptions. In these cases, the argument becomes unclear for the readers. Overlooked assumptions occur accidently while hidden assumptions are those that are concealed on purpose.

Activity 5 Hidden or overlooked assumptions

Consider these lateral thinking puzzles. In most cases to solve them, you need to uncover the hidden assumption. Our assumptions may be attributed to individual, collective, cultural and societal conditioning. Cognitive biases may also affect our ability to discover assumptions and so it is necessary to be aware of cognitive biases that may impact our reasoning. The first one serves as an example

  1. The street lights were broken. There were no lights on the car. An old man wearing black clothes and black stepped into the road. The car managed to stop. How? - Perhaps, the car was self-driving with sensors that noticed the pedestrian. Sensors can work well whether is night or day. However, although the car had no lights and the man wore black, the time of day is not mentioned. Did you assume that it was night time? If so, that is a hidden assumption. The puzzle is designed to make readers assume it is night time. The answer is it is day time and so the driver can see the man easily.
  2. A man who could not swim fell into the sea. The water was white because of the waves. Yet, the man survived. How?
  3. There is a cabin on the side of a mountain. Three people are inside in the cabin. All three people are dead. How did they die?
  4. A man wearing a black mask went to a bank. He passed a note to the bank clerk. The clerk quickly passed him lots of money. The man left quickly. What happened?
  5. It is a hot windy afternoon. Bill and Hillary are in the living room. They are both dead. The window of the living room is open. The curtains are being blown by the wind. On the floor lie the bodies of Bill and Hillary. There is some water and broken glass on the floor. Neither Bill nor Monica are wearing any clothes. They are both naked! How did they die?
  6. A man and his son were rock climbing on a dangerous mountain. They both fell. The man was killed, but the son lived. The son was taken to hospital quickly. At the hospital, the old doctor looked at the young man and said, "I can't operate on this boy: he is my son." How is that possible?
  7. The police found a dead man in the desert. There were no tracks to the body. The man was wearing a backpack. He did not die of thirst or hunger. Something in the backpack caused his death. What was in backpack that led to his death?
  8. Yoshi has a special skill. He can predict the future. For example, he can guess the score of a football game with 100% accuracy. How can he do it?
  9. There is a very old invention still used now in some places. The invention allows people to see through walls. What is it?
  10. Two train tracks run parallel to each other, except for a short distance where they join and become one track over a narrow bridge. One morning, a train travels 100 kph on the bridge. Another train coming from the opposite direction also travels 100 kph onto the bridge. Neither train can stop on the short bridge, but there is no train crash. How is this possible?

Share your views with your partner and/or in the unit forum on ELMS.

flat earth

Rashomon effect

Activity 6 Kurosawa's Rashomon

Watch this video clip (8 min 41 sec) showing how four witnesses report the same event in four different ways.

Witness accounts of any event vary greatly. People standing from different vantage points see the same event from different angles. People may be paying little or much attention to the event. Their view of the event or participants may suffer from cognitive bias.

Activity 7 Hands up, don't shoot

Witness statements to many police officer involved shootings in the United States differ on whether the police were justified in their decision to shoot. Eye witness statements are notoriously unreliable, with witnessses often suffering from the Rashomon effect. When the victim is black, the popular press in the United States tend to focus on race with claims (which may or may not be justified) that the incident was caused by racial prejudice.

For a fuller picture of the "hands up, don't shoot" movement, check out the Wikipedia page.

crime scene

Fact vs. opinion

Activity 8 Thinking

Decide whether these statements are facts or opinion.

  1. Your teacher is alive.
  2. The chair in my empty office is stationary.
  3. The Earth is flat.
  4. The Earth goes around the sun.

Commentary on Fact vs. Opinion

  1. Your teacher is alive is a fact (I hope!). But, we use I think to express opinions.  So this is a fact, disguised as an opinion.
  2. The sun rises in the east appears to be a fact, but since the sun does not actually rise, but only appears to rise, this is not accurate and so is not factual.  The earth spins towards the east, and relative to our location the position of the sun in the sky appears to change, but in fact, it is the change in our position that causes this effect.
  3. Although the chair appears stationary in relation to the room, the whole room, building and Earth are all moving. Given that the equator rotates at just over 1000 miles per hour, then in Aizu-wakamatsu, Japan (at latitude 37.4948°) the rotational speed is 1000 x cos (37.4948°), which is around 980 miles per hour.  This estimate does not account for the movement of the earth around the sun at a speed of 67,000 miles per hour, nor the solar system`s revolution around the centre of the galaxy nor the galaxy`s movement in the universe.
  4. The pre-Socratic Flat Earth model viewed the earth as either a disk or a plane until the spherical Earth model became accepted as the norm.
  5. The geocentric model, or Ptolemaic system, viewed the Earth as the centre of the Universe for over 1500 years until the heliocentric model became accepted.

Facts are proven true by evidence, e.g. as in court cases that are used to prove the defendant is either guilty or innocent. Courts, however, get things wrong as do scientists. This means that what had been accepted as a fact for years was in fact an opinion. Facts need supporting evidence. The accuracy of the fact depends on the strength of the evidence. Some of the facts that we believe now are likely to be proven incorrect in the future.


Knowledge and application

Activity 9 Writing

Submit an annotated causality network via ELMS.

Identify the causes that result in the effect/event. Name each type of cause. Draw a causality network using blocks for causes and arrows to show the direction of causality. Label each block (C1, C2,...Cn) and provide a key. Your assigned effect/event is decided by the final digit of your student id number. See the list below for your assigned effect.

  • 1: crow's feet
  • 2: ezcema
  • 3: type 2 diabetes
  • 4: child obesity
  • 5: World war 1
  • 6: Falkland's war
  • 7: hikikomori (acute social withdrawal)
  • 8: stress (mental or emotional strain or tension)
  • 9: The highest TOEFL scores in Europe - Netherlands
  • 0: The lowest TOEFL scores in Asia - Japan


Make sure you can explain the following 8 concepts in simple English:

  1. root cause
  2. common cause (shared cause)
  3. rival cause (competing cause)
  4. proximal cause, distal cause
  5. necessary cause, sufficient cause
  6. Rashomon effect

Running count: 105 of 108 logical concepts covered so far.