Informal LogicFallacies of Presumption and Weak Induction

Complex Question

A complex question has a hidden assumption built in, so that any direct answer grants it.

Not started Jump to practice

A cousin of begging the question hides the assumption in a question instead of a premise.

Key idea

A complex question has a hidden assumption built in, so that any direct answer grants it.

Why it works

"Have you stopped forgetting your homework?" looks like a yes-or-no question. But "yes" admits you used to forget it, and "no" admits you still do. The question is really two: did you ever forget it, and do you still? A fair reply splits them apart.
A question that assumes its answer, and a fair version.

Worked example: Find the hidden claim

"Why are you always so rude to the new students?"
  1. The question assumes the person is always rude to new students.
  2. Any answer that starts "Because…" grants it.

Answer: Complex question. A fair reply: "I don't think I am. What did you see?"

Look for words like "again", "still", "stopped" and "why".
Complex questionWhat it assumes
Did you spend the club money on candy again?You spent it on candy before
Where did you hide my toy?You hid it
Are you still copying answers?You copied before

Common mistake

Answering the question instead of spotting the assumption. "Have you stopped forgetting your homework?" assumes you used to forget it. Before answering, ask: what would I be agreeing to with a yes, and with a no?

Practice

Pass with 3 right answers, the last 2 in a row. Each right answer earns 1 XP.

Loading practice…

Builds on

Leads to

This is one of the top rungs of Informal Logic.

Sources and further reading

  • OpenStax Introduction to Philosophy, 5.5 Informal Fallacies
  • Internet Encyclopedia of Philosophy, "Fallacies"
  • Patrick Hurley, A Concise Introduction to Logic, chapter 3 (fallacies of weak induction and presumption)
  • Aristotle, Sophistical Refutations (many questions)
@teddyrookbook GitHub