Steelman
Appeal to ignorance
Also called argumentum ad ignorantiam, argument from ignorance, absence-of-evidence fallacy.
Claiming something is true because it hasn’t been proven false, or false because it hasn’t been proven true.
What it is
Treating a lack of evidence against a claim as proof of it, or a lack of evidence for a claim as proof that it’s false, when the missing evidence isn’t good evidence either way.
The pattern
No one has proven X false, so X is true. Or: no one has proven X true, so X is false.
An example
“No one has ever proven that ghosts don’t exist, so they must be real.”
The absence of a disproof isn’t evidence for ghosts. The person making the claim needs positive evidence.
Why it fails
Not knowing is just not knowing. Many true things haven’t been proven yet and many false things haven’t been disproven. The argument quietly shifts the burden of proof onto whoever doubts the claim.
When it’s not a fallacy
Most lists skip this part. Calling a fair point a fallacy is a mistake too.
It can be fair when
- A thorough search was made that would very likely have found evidence if it existed. After checking every room, concluding “there’s no one else in the house” is fine.
- Procedural rules like “innocent until proven guilty” set who must prove what. A “not guilty” verdict doesn’t claim the defendant certainly didn’t do it.
Try one
A question from the app. The wrong answers are its usual look-alikes.
Gym. Trainer: “That new pre-workout came out last month. Nobody’s run a single safety study on it yet.” Client: “Right, and so far there’s not one report of anyone getting hurt. If it were dangerous, we’d have heard. I’m taking it. Which flavor do you like?” Trainer: “The blue one, I guess. Go easy on it.”
What’s the flaw?
The product is a month old and untested, so no reports of harm mostly means nobody has looked yet. Safety needs testing, not just a quiet first month.
A fair reply
“A month with no studies isn’t much of a check. Let’s wait until someone actually tests it.”
Often confused with
- Shifting the burden of proof
Shifting the burden of proof demands that others disprove your claim. Appeal to ignorance then treats their failure to do so as proof.
- Personal incredulity
Personal incredulity says “I can’t imagine how X could be true, so it isn’t”. The gap is in the arguer’s imagination rather than in the evidence.
Where the name comes from
Ad ignorantiam is Latin for “to ignorance”, and argument from ignorance is the English version. Ignorance here isn’t an insult. It means not knowing: the argument builds a conclusion out of what nobody knows yet. Absence-of-evidence fallacy names the move: treating “no evidence yet” as if it were evidence.
Named by John Locke in 1690 as the argumentum ad ignorantiam.
Sources
In the app
Practice spotting it on arguments that sound real.
Steelman has more examples of appeal to ignorance, how to answer it in a real conversation, and practice rounds that mix it with its look-alikes, so you learn the difference, not just the name. Coming soon to iPhone and Android.
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