Lecture Notes by Christopher Lay
Los Angeles Pierce College
Department of History, Philosophy, and Sociology
Mathew Van Cleave's 2016 Introduction to Logic and Critical Thinking
https://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=457
Chapter 3 "Evaluating Inductive Arguments and Probabilistic and Statistical Fallacies," § 4 "Causal Reasoning"
Identifying the condition that serves as the cause of an effect will sometimes depend on the context of the event.
According to my New Oxford American Dictionary, a condition is "a state of affairs that must exist or be brought about before something else is possible or permitted," a cause is something "that gives rise to an action, phenomenon, or condition," and an effect is " a change that is a result or consequence of an action or other cause."
Match E.G.
"When I strike a match it will produce a flame."
"It is natural to take the striking of the match as the cause that produces the effect of a flame."
"But what if the matchbook is wet? Or what if I happen to be in a vacuum in which there is no oxygen (such as in outer space)? If either of those things is the case, then the striking of the match will not produce a flame."
"So it isn’t simply the striking of the match that produces the flame, but a combination of the striking of the match together with a number of other conditions that must be in place in order for the striking of the match to create a flame."
"Which of those conditions we call the 'cause' depends in part on the context."
Complexity / Background Conditions
"[A]ny cause is more complex than just a simple event that produces some other event."
"[T]here are always multiple conditions that must be in place for any cause to occur. These conditions are called background conditions."
"[W]e often take for granted the background conditions in normal contexts and just refer to one particular event as the cause."
Conditions Necessary
"For just about any cause, there are a number of conditions that must be in place in order for the effect to occur. These are called necessary conditions (recall the discussion of necessary and sufficient conditions from chapter 2, section 2.7)."
For instance, "[w]e can use necessary conditions to diagnose what [goes] wrong in cases of malfunction. That is, we can consider each condition in turn in order to determine what caused the malfunction.
Recall: Excerpts of Chapter 2 "Formal Methods of Evaluating Arguments," § 7 "Conditionals" on Necessary and Sufficient Conditions
Conditions Sufficient
"[A] sufficient condition is one which if present will always bring about the effect."
Causal Generalizations
"Because the natural world functions in accordance with natural laws (such as the laws of physics), causes can be generalized."
"Such causal generalizations are often parts of explanations."
"Causal generalizations have a particular form: For any x, if x has the feature(s) F, then x has the feature G."
"Being able to determine when causal generalizations are true is an important part of becoming a critical thinker."
"Since in both scientific and every day contexts we rely on causal generalizations in explaining and understanding our world, the ability to assess when a causal generalization is true is an important skill."
Determining Causes
[Consider reading Excerpts of Mill's System of Logic, Book III: Of Induction, Chapter VIII: "Of The Four Methods Of Experimental Inquiry"]
Concomitant Variations
"In concomitant variation we look for how things vary vis-à-vis each other."
"When two things are positively correlated, as one increases, the other also increases at a similar rate (or as one decreases, the other decreases at a similar rate)."
"In contrast, when two things are negatively correlated, as one increases, the other decreases at similar rate (or vice versa)."
Correlation ≠ Causation
"[W]e cannot directly infer causation from correlation. Correlation is not causation."
"If A and B are positively correlated, then there are four distinct possibilities regarding what the cause is: A is the cause of B; B is the cause of A; [s]ome third thing, C, is the cause of both A and B increasing; or [t]he correlation is accidental."
Background Knowledge
"In order to infer what causes what in a correlation, we must rely on our general background knowledge (i.e., things we know to be true about the world), our scientific knowledge, and possibly further scientific testing."
Some Third Thing
"Sometimes two things can be correlated without either one causing the other. Rather, some third thing is causing them both."
"For example, suppose that Bob discovers a correlation between waking up with all his clothes on and waking up with a headache. Bob might try to infer that sleeping with all his clothes on causes headaches, but there is probably a better explanation than that. It is more likely that Bob’s drinking too much the night before caused him to pass out in his bed with all his clothes on, as well as his headache. In this scenario, Bob’s inebriation is the common cause of both his headache and his clothes being on in bed."
Accidental Correlations
"Sometimes correlations are merely accidental, meaning that there is no causal relationship between them at all."
"What makes [a correlation] accidental is that we have no theory that would make sense of how they could be causally related."
"This just goes to show that it isn’t simply the correlation that allows us to infer a cause, but, rather, some additional background theory, scientific theory, or other evidence that establishes one thing as causing another."
"We can explain the relationship between correlation and causation using the concepts of necessary and sufficient conditions (first introduced in chapter 2): correlation is a necessary condition for causation, but it is not a sufficient condition for causation."
False Cause Fallacy
"Our discussion of causes has shown that we cannot say that just because A precedes B or is correlated with B, that A caused B. To claim that since A precedes or correlates with B, A must therefore be the cause of B is to commit what is called the false cause fallacy."
"As we’ve seen, false cause fallacies occur any time someone assumes that two events that are correlated must be in a causal relationship, or that since one event precedes another, it must cause the other."
("The false cause fallacy is sometimes called the 'post hoc' fallacy. 'Post hoc' is short for the Latin phrase, 'post hoc ergo propter hoc,' which means 'before this therefore because of this.'")
Avoiding the False Cause Fallacy
"To avoid the false cause fallacy, one must look more carefully into the relationship between A and B to determine whether there is a true cause or just a common cause or accidental correlation."
"Common causes and accidental correlations are more common than one might think."
Exercise 26
"For each of the following correlations, use your background knowledge to determine whether A causes B, B causes A, a common cause C is the cause of both A and B, or the correlations is accidental."
1. "There is a positive correlation between U.S. spending on science, space, and technology (A) and suicides by hanging, strangulation, and suffocation (B)."
"[U]se your background knowledge to determine whether A causes B, B causes A, a common cause C is the cause of both A and B, or the correlations is accidental."
2. "There is a positive correlation between our dog Charlie’s weight (A) and the amount of time we spend away from home (B). That is, the more time we spend away from home, the heavier Charlie gets (and the more we are at home, the lighter Charlie is."
"[U]se your background knowledge to determine whether A causes B, B causes A, a common cause C is the cause of both A and B, or the correlations is accidental."
3. "The height of the tree in our front yard (A) positively correlates with the height of the shrub in our backyard (B)."
"[U]se your background knowledge to determine whether A causes B, B causes A, a common cause C is the cause of both A and B, or the correlations is accidental."
4. "There is a negative correlation between the number of suicide bombings in the U.S. (A) and the number of hairs on a particular U.S President’s head (B)."