Self-study
Support The return of organic wastes to the soil is a good solution to waste disposal problems only if the wastes are nontoxic and not too much energy is expended in transporting them. ██ ███████████ ███████ ████████ ███ ██████ ███ ████████ ███ ███ ███ ████ ██████ ██ ████████ ██ ████████████ █████ ██████ █████████ ███████ ██████ ██ ███ ████ ██ █ ████ ███ ███ ███████████ ███████ █████ ██ █████ █████ █████ ████████ █████████
Method of Reasoning
The argument starts by saying that for something (returning waste to soil) to have a certain characteristic (to be a good solution), it must have certain properties (nontoxic and energy-efficient). It then notes one instance of this thing that has these properties (returning waste to soil in small-scale farming), and concludes that this instance has the characteristic (returning waste to soil in small-scale farming is a good solution).
Identify and Describe Flaw
This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The author assumes that because returning waste to soil in small-scale farming is nontoxic and energy-efficient, it’s a good solution. But according to the premises, “nontoxic and energy-efficient” are necessary, not sufficient. So just because this method is nontoxic and energy-efficient doesn’t necessarily mean that it’s a good solution.
22.
Which one of the following ████████ ██████ █████████ ████ ███████ ██ ███ ██████ █████████ █████████ ██ ███ ████████ ██████
a
Plants thrive if ████ ███ ██ █████████ ██ █████████ ██████ ███ ██████████ ██ ████████████ ██████ ███ ██ ███████ ███████████ ██ ███ ██████ █████ ██ ███ ████████████ ████████ ██████ ███ ██ ███████ ████ ███ █████ ███ █████
Wrong flaw. This presents three properties that are sufficient for a plant to thrive. Since greenhouse plants have these properties, commercially produced plants are healthy when you buy them. This is a pretty good argument; it just assumes that commercially produced plants are grown in greenhouses and that “healthy” and “thriving” are the same. The stimulus, meanwhile, presents properties that are necessary for a method to be good, then concludes that the method is good because it has those properties.
b
When every country ███ █████ ██████ ██ ████████ █████ ████ ██ ███ ████ ██ █████ ████ ████ █████████████ ██ ███████ ████ ███████ █ ███ ███ ████ ███████ ██ ████████ ███ ███ ██ ██████████ ███ █████████████ ██ ███████ ████ ████ ███ ███████ ███████ ██ █████ ████ ████
Wrong flaw. This says that in 20 years, all countries will have equal market access and will be able to optimize resources because of globalization. It then concludes that globalization will bring “the desired results,” but never establishes whether the ability to optimize resources is the desired result of globalized markets. The stimulus, meanwhile, presents conditions that are necessary for a method to be good, and concludes that one method is good because it meets the necessary conditions.
c
To be viable, █ ████████ ████ ████ ██ ██████ ███████████████ ██████████ ███ ██████████ ██ █ ██████ ███████ ████ ████ ███ █ ███████ ███████████ ███████ ███ ███ █████ ███████████ ██ ██ ██ ███████
The argument starts by saying that for something (a business idea) to have a certain characteristic (to be viable), it must have certain properties (clear, cost-effective, practical, and responsive). It then notes one instance of this thing that has these properties (your business idea), and concludes that this instance has the characteristic (your business idea is viable). This is the same sufficiency/necessity confusion; just because your business idea has the necessary properties doesn’t mean it’s viable.
d
Those competitors—and only ███████████ ████ ███ ██ ███ █████████ ████████ ███ ████████ ███ ███ ██████ ████ ████ ██ █████ ██ █████ ██ ████ ██ ██ █████████ ███████ ███ ████ ██████ ███ █████ ███ ██ █████ ███ ███ █████ ███████████ █████████ ███ ████████████ ███ ████ ███ ███ █████████ ██ ███ ███ █████████
No flaw. This starts with a biconditional statement: one is eligible for the award if and only if one meets all the criteria. It then correctly concludes that, since you meet all the criteria, you are eligible for the award.
e
A meal is ██████████ ████ ██ ██ ████████ ████ █████████████ ███ ████████ ██████ ██ ███████ ██ ███ ████████ ██ ████ █ ███ ███ █████ ████ ████ ████ ██ ████ █ ███ ███ █████ ███ ███ ███████████
Wrong flaw. This starts by presenting two necessary conditions for a meal to be nutritious. It concludes that the lunch was not nutritious. It doesn’t tell us whether the lunch met the necessary conditions (did the other 20% contain carbs and protein?). Even if it did meet these conditions, we wouldn’t know whether the lunch was nutritious. The stimulus, meanwhile, presents necessary conditions for a method to be good, and then concludes that the method is good, since it does meet the conditions.