Identifying Assumptions in Arguments Flashcards

Argument: 'The fact that ancient peoples built the pyramids with primitive tools proves humans had help from extraterrestrials.' What assumption does this argument depend on?

Answer: The pyramids could not have been built using only human ingenuity and labor with available tools

The argument assumes it is impossible for humans to have accomplished this feat alone, making extraterrestrial assistance the only remaining explanation.

Argument: 'Because no scientific study has proven that this supplement is harmful, it is safe to take.' What assumption does this make?

Answer: Absence of proof of harm is equivalent to proof of safety

The argument treats the lack of evidence of harm as positive evidence of safety, assuming these two things are equivalent.

Argument: 'Our team's productivity increased after we switched to four-day work weeks; we should make this change permanent.' What assumption underlies this recommendation?

Answer: The productivity increase will be sustained long-term rather than being a temporary novelty effect

The argument assumes the early productivity gains reflect a durable change rather than a short-term motivational boost from novelty.

Argument: 'Because the two candidates have nearly identical policy platforms, voters should choose based on personality.' What assumption is present?

Answer: Policy platform similarity means the candidates' actual governing behavior would also be identical

The argument assumes that similar stated positions mean governing outcomes would also be equivalent, making other factors the only meaningful differentiator.

Argument: 'This investment advisor has achieved above-average returns for the past five years, so you should trust her with your savings.' What assumption is this based on?

Answer: Past investment performance is a reliable predictor of future performance

The argument assumes historical returns will continue, ignoring the well-known principle that past performance does not guarantee future results.

Argument: 'People who own dogs live longer on average than people who don't; getting a dog will therefore extend your life.' What assumption is made?

Answer: Dog ownership itself extends life rather than both being explained by a common factor such as better general health or social connectedness

The argument assumes the correlation is causal, ignoring that healthier or more socially connected people may be more likely to own dogs.

Argument: 'The senator voted against the environmental protection bill, so she clearly does not care about the environment.' What assumption does this argument make?

Answer: Voting against a bill means opposing its stated goal, rather than objecting to specific provisions, costs, or methods

The argument assumes opposition to the bill equals opposition to its environmental goals, ignoring that one can support an aim while opposing a specific approach.