Self-study
Support Congenial guests and a plentiful supply of good things to eat and drink will ensure a successful dinner party. █████ ██████ ███ ████████ ████ ████ ██████ ██ ███ ███ █████ ███ ███ ██████ ███ ███ █████████ ███████ ███ ██████ █████ ██ ███████ ██ ██ █ ████████
Method of Reasoning
This argument starts by providing a general conditional rule: if there are congenial guests and a plentiful supply of good things to eat and drink, a successful dinner party is ensured. In other words, if there are both congenial guests and an abundant supply of good food and drink, that is a sufficient condition for a successful dinner party.
The stimulus then tries to apply that rule to a specific case: since Sylvia has plentiful food and drink and has invited congenial guests, her dinner party will be a success. In other words, the argument tries to show that Sylvia has satisfied the sufficient condition, and thus that the necessary condition — a successful dinner party — will follow.
Identify and Describe Flaw
The argument gives us a conditional rule with a two-part sufficient condition. It then tries to apply that rule to a specific case, which doesn't actually meet both parts of the sufficient condition. While we know for sure that Sylvia has congenial guests, we only know that she has plentiful food and drink — we don't know that she has plentiful good food and drink.
The difference depends on the one adjective "good", but because we don't know if Sylvia's food and drink is good or not, we can only say for sure that she satisfies one part of the sufficient condition: having congenial guests. Since we can't say that Sylvia's situation fulfills the sufficient condition of the conditional rule, we can't conclude that the necessary condition will follow — i.e. that her dinner party will be successful.
Since this is a Parallel Flaw question, it will be useful to describe the flawed pattern of reasoning in more general terms. At the highest level, we're looking for an answer choice that assumes a specific case meets the sufficient condition of a rule, when it actually doesn't. More specifically, we're likely looking for an answer choice that provides a conditional rule with a multi-part sufficient condition, then concludes that a certain case will follow that rule when it only meets part of the sufficient condition.
22.
The pattern of flawed reasoning █████████ ██ ███ ████████ █████ ██ ████ ███████ ██ ████ █████████ ██ █████ ███ ██ ███ ██████████
a
The right ingredients, ████████ ████████ ███ █████ ██ █ ████████ ████ ████ ██████ ███████ █ ██████████ █████ █████ █████ ███ ████████ ████████ ███ █████ ████████████ ███ ████ ██ ███████ ██ ████ ███ ████ ██ ███ █████ ██ ██ █ ████████ █████
This isn't flawed. We know Emily has met part of the sufficient condition to produce a well-baked cake: properly combining the ingredients. For this answer choice to match the pattern in the stimulus, it would need to conclude that Emily definitely will produce a well-baked cake, without telling us whether she is baking it in a reliable oven or not. Instead, the answer choice just concludes that if she meets the other part of the sufficient condition — using a reliable oven — then the necessary condition will follow, which is a valid statement.
b
If corn is █████ ████ ███ █████ ███ ███ █████████ ████ ████ ██████ ██ █████ ███ ██████ █████ ██████ ██████ ██ ██████ ████ ███ ████ ██ █████ ██ █████ ██ ██████ ██ ████ ██ ███████ ████ ██ ████ ██ ███ ██ █████ ███ █████ ███
This is a different flaw. It gives us a sufficient condition for cooking corn to produce a moist and sweet dish. It then assumes that since George wants to produce a moist dish, he will definitely try to meet the sufficient condition in cooking his corn. We don't know if George wants his dish to be sweet as well as moist, or that this method is the only one for producing a moist corn dish, or even that George is aware of this method of cooking corn. While this is a flawed argument, it's a different flaw from what we have in the stimulus, where a specific case is assumed to trigger a sufficient condition when it only fulfills part of it.
c
Making pie dough █████ ███ █████ ███ ██████████ ████████ ███ █████ ██████ ███████ ██ ███ ████ ██████ █ █████ ██████ ██████ ██████████ ███████ ███ ███ █████ ██████ ███████ ██ ████ ███ █████ ██ ████ ███ █████ ██ ██████ ███ ███ ███ ██ ███████ ██ ████ █ █████ ██████
This is a powerful trap answer, especially if you are unsure what the flaw in the stimulus is and relying on structural clues. This answer choice matches a lot of the wording and structure of the stimulus, and like the stimulus, it presents a conditional rule whose sufficient condition has two very wordy parts.
The difference is that in this case, both parts of the sufficient condition are actually met: Andrew both used ice water to make his dough and thoroughly chilled it before rolling it out, which satisfies all parts of the sufficient condition. Thus, it's valid to conclude the necessary condition will follow: Andrew will have a flaky pie crust. So this answer choice, while looking very similar to the stimulus, doesn't actually contain a flaw.
d
If soup is ████ ████ █ █████████████ ████ █████ ███ █████ ████████████ ██ ████ ██████ ██ ███████ ██ ███████ █████ ██ ███ ████ █████ ██████ █████ ████ ████ █████ ████████████ ███ █████████ ████ ██ ███████ ██ ██ ███████ ██ ███████
This is correct. This answer choice gives us a sufficient condition with two parts: having well-seasoned meat stock and using fresh ingredients. If both these things are true of a soup, that soup will always be welcome at dinner. Then the answer choice tries to apply that rule to Arnold's case, assuming that he meets the sufficient condition and that his soup will therefore be welcome at dinner.
But we only know that Arnold used fresh ingredients — we don't know if he used a well-seasoned meat stock. Thus, we can't say if his soup actually triggers the sufficient condition. This is the same flaw pattern as in the stimulus.
e
Fresh greens, carefully ██████ ███ ██████ ████ █ █████ █████████ ██████ ███████ █ ██████████ ██████ █████ █████ ███ █████████ ██ █████████████ █████ ████████ ███ █████ ██████ ███ █████ ███████ ██ █████ ███ ██████ ████ ██ █ ██████████ ████
This is a different flaw. This gives us a sufficient condition — carefully washed fresh greens, with a light dressing — for a given outcome: a refreshing salad. It then tells us that since Tisha does not meet the sufficient condition — she never washes her fresh greens — she will never produce a refreshing salad. This confuses the sufficient condition for a necessary one, which is a different flaw from what is in the stimulus.