Self-study
Marketing agent: A survey of my business clients reveals that, Support of those who made a profit last year, 90 percent made at least $100,000 in profit for the year. ██ █████ ██████ ███ ███ ██ █████ ██████████ ████ ██ ██████ ██████ ██ ████ ████ ████████ ███ ██ ███████ ██ ██ ████████ ███████ █████████ █████ ███████ ██ █████ ███████ ████ █████
Summarize Argument
The marketing agent concludes that 90% of his clients increased their profits at least tenfold last year. He supports this by saying that 90% of his clients who made a profit last year earned at least $100,000, and none of them had earned more than $10,000 in previous years.
Identify and Describe Flaw
The marketing agent concludes that 90% of his clients increased their profit tenfold last year based only on the fact that 90% of his profitable clients did so.
This is the part-to-whole flaw. The agent assumes that what’s true of a subset of his clients applies to all of his clients. But it’s possible that only a few clients were profitable last year, and while 90% of them increased their profits tenfold, most clients didn’t profit at all.
9.
The reasoning in the marketing ███████ ████████ ██ ████ ██████████ ██ █████████ ██ ███ ███████ ████ ███ ████████
a
overlooks the possibility ████ ███ ████████ ███████ ███ ████ ████ ████ ████████ ████ ████ ████ ████ ████████ ████ ████ ████████
This doesn’t impact the agent’s conclusion. Even if these clients made only slightly more than $100,000, they still increased their profits tenfold. Either way, he assumes that what’s true of his profitable clients is also true of all his clients.
b
fails to explain ███ ████ ██ ███ ████████ ███████ ███ ████ █ ██████ ███ ███ ████████ █████ ███████ ██ █████ ███████ ████ ████
The agent doesn’t explain why 10% of his profitable clients didn’t increase their profits tenfold, but he doesn’t need to. He only addresses those clients who did increase their profits tenfold, assuming that they’re representative of all his clients.
c
draws a conclusion █████ ███ ██ ███ ████████ ███████ ████ ████████ █████ ███ ████████ ███████ ███ ████ █ ██████ ████ ████
The agent concludes that all his clients increased their profits tenfold last year based on premises about his profitable clients. But what if he only had a few profitable clients? In that case, it’s not true that 90% of his clients increased their profits tenfold.
d
treats conditions that ███ ██████████ ███ ██████ █ ██████ ██ ██████ ████ ███ █████████ ███ ██████ █ ██████
This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The marketing agent doesn’t make this mistake; his argument doesn’t rely on conditional logic. Instead, he assumes that what is true of one subset of his clients is also true of all his clients.
e
overlooks the possibility ████ ███ ███ ██ ███ ████████ ███████ ████ ██ ██████ ██████ ██ ████ ████ ███████ ████ ████
The marketing agent actually allows for this possibility. 90% of his profitable clients made $100,000, but the other 10% might have made less than $10,000. Also, the clients that were not profitable certainly made less than $10,000 because they didn't make any profit at all.