Lesson · 4 min Gentle
Motive Is Not a Disproof
In one line A motive is a reason to check the evidence, not a way to skip it.
A motive can explain why someone spoke. It cannot, by itself, explain whether the speech is true. Wanting a result is a reason to look harder at the evidence. It is not a substitute for looking.
This is the reverse of a cheap cynicism. “They would say that” is sometimes a useful alarm. The alarm is supposed to send you to the claim, not to retire it.
Keep two columns. One is “why they might bend this.” The other is “what would still be true if they did not.” A finding that survives the second column has outlived the motive.
The funded study
A village pays a scientist to test its own well water. A critic says, “Paid by the village, therefore false,” and does not read the method. A second critic reads the method, finds a missing control, and says so.
The payment was a reason to read carefully. Only the missing control was a reason to doubt the result. The first critic stopped at the biography.
Try this today Note who paid for or benefits from a claim, then check the method and data anyway.
Cite or share this lesson
A plain reference you can paste into notes or an essay:
Quest2Reason. “Motive Is Not a Disproof.” https://quest2reason.com/learn/lesson/motive. Accessed 13 November 2026.
Sources
- Stanford Encyclopedia of Philosophy, “Fallacies” — Circumstantial ad hominem: when a person’s situation is offered in place of a reply.
- John Locke, An Essay concerning Human Understanding — Book IV names the argument ad hominem, in an older sense: pressing a person with their own principles.