Ad Fidentia
Attacking the person's self-confidence in place of the argument or the evidence. This fallacy undermines the opponent's certainty to avoid addressing the actual reasoning.
THE IDEA
Description
Attacking the person's self-confidence in place of the argument or the evidence.
Logical Form
Person A makes claim X. Person B attacks Person A's self-confidence in believing claim X. Therefore, claim X is false.
Example #1
Person A: I am convinced that this policy will improve the economy. Person B: You sound so uncertain. Are you even sure about that? Explanation: Person B focuses on Person A’s confidence rather than the policy evidence. If that observation is used to dismiss the claim, the reasoning is fallacious. Asking about uncertainty can be reasonable when it helps clarify the claim’s support.
Example #2
Person A: The evidence for evolution is overwhelmingly supported by the data. Person B: But you don't know for certain, do you? You might just be overconfident. Explanation: A lack of absolute certainty does not erase evidence. Person B would need to identify a problem with the data or inference to rebut Person A’s claim. A question about overconfidence is relevant if it asks whether the stated confidence matches the evidence; it is fallacious when it substitutes for addressing that evidence.
Exception
When one claims certainty for something where certainty is unknowable, it is your duty to point it out.
Tip
Have confidence that you are probably or even very probably right, but avoid dogmatic certainty at all costs in areas where certainty is unknowable.
When to use it
During a political debate, when a speaker says 'You don't sound confident about your own proposal' without addressing the proposal's flaws.
In a scientific discussion, when a person counters evidence with 'You can't be 100% sure, so your argument is weak.'
In a workplace negotiation, when one party attacks the other's self-assurance to gain an advantage rather than discussing facts.
FROM THEORY TO EVERYDAY LIFE
In practice
Example #1: Attacking uncertainty in a policy debate
Person A: "I am convinced that this policy will improve the economy." Person B: "You sound so uncertain. Are you even sure about that?" Explanation: This becomes fallacious if Person B treats A’s uncertain manner as a reason to reject the policy without examining its merits.
Example #2: Overconfidence accusation in evolution debate
Person A: "The evidence for evolution is overwhelmingly supported by the data." Person B: "But you don't know for certain, do you? You might just be overconfident." Explanation: Requiring absolute certainty can be a way of dismissing evidence without addressing it. A genuine question about whether confidence is proportionate to the evidence is different.
A MOMENT TO REFLECT
Put it to work.
Think of a recent argument where someone questioned your confidence instead of your reasoning. How did that affect the debate?
How can you distinguish between a legitimate request for clarification and an ad fidentia attack?
In what situations might pointing out someone's uncertainty be a valid critique rather than a fallacy?
CONTINUE THE CONVERSATION
Source texts
- Logically Fallacious - The Ultimate Collection of Over 300 Logical Fallacies