Self-study
Support Paleomycologists, scientists who study ancient forms of fungi, are invariably acquainted with the scholarly publications of all other paleomycologists. █████████ ███████ ██ ██████████ ████ ███ █████████ ████████████ ██ █████████ ██████████ ███ ██ █ ████████████████ ██████████ █████████ ███████ ████ ████ ██ █ ████████████████
Method of Reasoning
The argument starts by describing one characteristic of members of a group (all paleomycologists are familiar with all the works of all other paleomycologists), describes a characteristic of one individual (Professor Mansour is familiar with the publications of Professor DeAngelis, a paleomycologist), and then concludes that the individual belongs to the group (Professor Mansour must be a paleomycologist).
Identify and Describe Flaw
The argument commits two flaws. First, the argument fails to trigger the necessary condition of a conditional relationship. The argument describes the conditional relationship that all paleomycologists know all the scholarly publications of all other paleomycologists, then says that Professor Mansour knows Professor DeAngelis’ works and, as a result, concludes that Professor Mansour is a paleomycologist. However, it’s not clear that knowing Professor DeAngelis’ works is the same as knowing all other paleomycologists’ scholarly publications.
Second, the argument commits a cookie-cutter “confusing necessary and sufficient conditions” flaw. Even if Professor Mansour being familiar with Professor DeAngelis’ scholarly publications is the same as knowing all other paleomycologist’s scholarly publications, that doesn’t necessarily imply that Professor Mansour is a paleomycologist. Confirming a necessary condition in a conditional relationship doesn’t necessarily confirm the sufficient condition.
24.
The flawed pattern of reasoning ██ ███ ████████ █████ ██ ████ ███████ ██ ████ ██ █████ ███ ██ ███ █████████ ██████████
a
When a flight ██ ██████ ████████ ██ ████████ ███ ██████████ ██████ ████████ ███████ ███ ████ ███████ ██ ████ ███ ██████████ ███ ████ █████ ████████████ █████ ████████ ██████████ ██████ ██ ██████ ███ ████████ ███ █████ ██████ ████ ████ ████ ████ █ ███████ ██████ ████████ ███████
The argument starts by describing one characteristic of members of a group (when a Global flight is delayed, all connecting Global flights are delayed), describes a characteristic of one individual (Frieda’s connecting Global flight was delayed), and then concludes that the individual belongs to the group (Frieda’s first flight must’ve been a delayed Global flight). This commits the same flaw as the stimulus of confusing sufficiency with necessity. Just because Frieda’s connecting flight was a Global flight and it was delayed doesn’t necessarily imply that her first flight was a Global flight.
b
Any time that ███ ██ ██████ █████████ █████ ██████ ██████ ██████ █ ██████ ███ █████ ██████ ██ ████ █████ ████ ██ ████ ██████ ████ ██████ █████ ████ ██ ████████ █████ ██████ ██████ ██████ █ █████ ████ █████ ███ █████████ █████ ██████ ██████ ███ ███ ████ ██ ████ ██████ ████ █████ ████ █████
Wrong flaw. (B) confuses sufficiency with necessity but in a different way than the stimulus. (B) says that because no Global ticket agents missed a shift last week, and we know that when Global ticket agents miss a shift all other agents must work harder than usual, no Global ticket agents had to work harder than usual last week. However, negating a sufficient condition in a relationship doesn’t necessarily negate the necessary condition(s) in the relationship. Alternatively, the stimulus errs by assuming that confirming a necessary condition in a relationship also confirms the sufficient condition in a relationship.
c
Any time the █████ ██ ████ ██████████ ██████ █████████ ████████ ████████ ███ ███ ██████ ██ ███████████ ███ █████ ██ ████ █████████ ███████ █████ ████ █████ ██████████ ██████ ████████ ████ ████ ████ █ ██████ ████ █████
Wrong flaw. (C) says that when the price of something (fuel) decreases, a company’s (Global’s) expenses decrease, and the company’s income is unaffected. (C) erroneously concludes that because the price of fuel went down last year, we can infer that Global made a profit last year. The stimulus, on the other hand, fails to trigger a necessary condition and confuses sufficiency with necessity.
d
All employees of ██████ ████████ ███ ███████████ ██ ███ ██████████ ████ █████ ████ ████ ████ ████ ███ ███████ █ ████ ██ █████ █████ ███ ████ ████ ██████ ████████ ███ █████ ██████ ██ ███ █████████ ██ ████ ████ ██ ████████████ ██ ████████ ██████████ █████
Wrong flaw. (D) says that because Global employees can participate in the company’s retirement plan after being with the company for at least a year, and Gavin has been with Global for three years, we know that Gavin participates in the plan. However, we have no way of knowing whether Gavin participates in the plan. Alternatively, the stimulus errs because of failing to trigger a necessary condition in a conditional relationship and conflating sufficiency with necessity.
e
Whenever a competitor ██ ██████ ████████ ███████ ███ ██████ ██████ ████ ██████ ████ ██ ████ ███████████ ██████ ███████ ████ ██████████ ████ ████ ████ ██ ███ ███ ████ ███████ ██████████ ██████ ████ ████ ███████ ███ █████ ████ ████ ██ █████ ██████████ ██ ███ ████████████ ██████
Wrong flaw. (E) describes a conditional relationship (when a competitor of Global reduces its fares, Global must also reduce its fares or it’ll lose passengers), denies the necessary condition (Global didn’t lose passengers last year), and then arrives at an unsupported conclusion (that Global must’ve reduced its fairs). It’s entirely possible that Global didn’t lose passengers because it didn’t have to cut fares, not because it cut fares to compete with a competitor. In the stimulus, meanwhile, the argument errs because it just didn’t confirm the necessary condition in a conditional relationship and confused sufficiency with necessity.