Why Uncertainty is Deeply Uncomfortable.
And as we saw in Part 1, System 1 — the fast, automatic, effortless part of your thinking — is motivated to make discomfort go away as quickly as possible.
So when System 1 meets a gap, a thing nobody has proven either way, it does not sit patiently in the “we don’t know yet” box.
That box feels terrible.
What happens next is subtle, and it is the whole reason this fallacy is so hard to catch in yourself. The desire shapeshifts. It starts out as a desire to know. It ends up as a desire for relief. And once that swap happens, any answer that quiets the itch will do — because the mind is no longer solving for truth. It is solving for comfort.
That is how the gap gets filled. Not with evidence. With whatever closes the loop fastest.
Here is the part worth sitting with. The gap does not get filled at random.
If it did, you would be wrong in every direction equally — sometimes landing on a conclusion you like, sometimes on one you hate. That is not what happens. The gap gets filled with your existing hopes, fears, and loyalties. It gets filled with the answer you were already carrying.
“I don’t know” becomes “so I’m probably right.”
And it happens before your slow, careful, deliberate System 2 mind has even sat down.
Once you know the shape of it, you start seeing it everywhere. Here are four of the most famous — and infamous — variations. Let’s begin with the one that’s probably going to offend some of you.
The God of the Gaps. Take a gap in scientific knowledge and “resolve” it by introducing an unprovable entity. Science does not fully understand the origin of the universe. That is a real gap. But plugging in “God” does not solve it — it swaps an unexplained natural mystery for an even bigger supernatural one. That’s the ultimate shortcut for relieving psychological discomfort. “We don’t know yet” is not permission to insert your preferred answer and declare the case closed.
The Red Scare. Senator Joseph McCarthy built an entire career on a single move: name a person, produce no evidence, and treat the empty file as though it settled the question. No proof of innocence — therefore, guilt. An entire era of ruined lives ran on the argument from ignorance wearing a flag pin.
The paranormal. “No one has been able to explain that light in the sky — so it’s extraterrestrial.” The failure of every ordinary explanation gets counted as a point for the extraordinary one. But “unexplained” and “explained by my theory” are two very different concepts, and the distance between them is exactly where the fallacy lives.
The marketing whisperer. “There’s no evidence our product causes any harm.” Often true. Often meaningless — because no one has looked. The absence of a warning label is not a clean bill of health.
Now here’s what most people miss
Not every “we haven’t proven it” is a fallacy.
Sometimes the absence of proof is exactly the rule we should be following. Telling the difference is the whole skill — and it is the part almost nobody teaches.
Think about a courtroom. “Innocent until proven guilty” sounds like the argument from ignorance: we have not proven guilt, so we treat you as not guilty. But it is not a fallacy, and the reason why is worth understanding precisely.
It is a deliberate institutional rule about where to place the burden of proof, and about who pays for a mistake. The court is not claiming that you are innocent as a fact about reality. It is refusing to act against you until there is sufficient evidence to warrant acting. That is not lazy thinking. That is the burden of proof working exactly as designed.
What a lot of people miss — including, occasionally, some lawyers — is that a criminal justice system tests strictly for guilt, not for innocence. Those are two different standards. In a criminal trial, the binary is Guilty or Not Guilty. Not “guilty or innocent.” That distinction is what keeps the whole system from collapsing on itself, because a system that required defendants to prove their innocence would convict nearly everyone who could not.
Science does the same thing with the null hypothesis. We assume no effect until the evidence shows an effect. The burden of proof is embedded in the test itself, and the conclusion becomes whatever the evidence shows. That’s it.
To be pedantic for a moment: in the scientific method, the claim is the hypothesis. The test determines whether that hypothesis is accepted or rejected, with the default being null. The method treats “no effect” as the default presumption. So, just like a jury, science never issues a verdict of “innocent.” It only decides whether the evidence is strong enough to convict the data of showing a real effect — of existing — or whether the verdict is simply not guilty of existing.
So how do you tell the honest version from the fallacy? Ask what is actually being claimed.
If someone says, “We haven’t proven it, so let’s not act as though we have” — that is the burden of proof operating rationally. It withholds action. It makes no claim about reality.
If someone says, “You haven’t proven it false, so it must be true” — that is the argument from ignorance fallacy. It asserts a fact about reality based on a gap.
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Why is that illegitimate? Because the standard for any claim requires exactly one thing: actual evidence. Failing to disprove Option A is not positive proof of Option B. It is a magician’s trick — hiding a total lack of evidence by pointing at a flaw in the other side, and hoping you watch the wrong hand.
Because it’s easier. Way easier.
It amounts to: “Well, you don’t know, and I don’t know, so I’m going with what I’d like it to be.”
“I don’t know” is one of the most uncomfortable sentences a mind can hold, and System 1 is built to end that discomfort before System 2 even wakes up. By the time your slow, reasonable mind arrives and asks the right question — wait, who actually owes the proof here? — the hole has already been filled, and the feeling of closure has already set like concrete.
That feeling is the tell. Closure that arrives fast, on a question that was genuinely open, is almost never the product of reasoning. It is the product of relief.
So the practice is small and unglamorous: when you notice a conclusion showing up quickly on a question nobody has settled, stop and ask who owes the proof. Not who has the better story. Who owes the evidence.
In Part 3, we get to the fun part — how to get a lazy System 2 off the couch and into the room while there’s still time to intervene on a System 1 error. That’s the part where we get to watch ourselves become smarter.
Until next time — think critically, and choose wisely.
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References
Coffin v. United States, 156 U.S. 432 (1895).
Coulson, C. A. (1955). Science and Christian belief. University of North Carolina Press.
Drummond, H. (1894). The Lowell lectures on the ascent of man. Hodder & Stoughton.
Fisher, R. A. (1935). The design of experiments. Oliver & Boyd.
Greenland, S., Senn, S. J., Rothman, K. J., Carlin, J. B., Poole, C., Goodman, S. N., & Altman, D. G. (2016). Statistical tests, P values, confidence intervals, and power: A guide to misinterpretations. European Journal of Epidemiology, 31(4), 337–350. https://doi.org/10.1007/s10654-016-0149-3
Griffith, R. (1987). The politics of fear: Joseph R. McCarthy and the Senate (2nd ed.). University of Massachusetts Press.
In re Winship, 397 U.S. 358 (1970).
Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.
Kruglanski, A. W., & Webster, D. M. (1996). Motivated closing of the mind: “Seizing” and “freezing.” Psychological Review, 103(2), 263–283. https://doi.org/10.1037/0033-295X.103.2.263
Kunda, Z. (1990). The case for motivated reasoning. Psychological Bulletin, 108(3), 480–498. https://doi.org/10.1037/0033-2909.108.3.480
Locke, J. (1975). An essay concerning human understanding (P. H. Nidditch, Ed.). Clarendon Press. (Original work published 1690)
Nickerson, R. S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2(2), 175–220. https://doi.org/10.1037/1089-2680.2.2.175
Schrecker, E. (1998). Many are the crimes: McCarthyism in America. Little, Brown.
Stanovich, K. E., & West, R. F. (2000). Individual differences in reasoning: Implications for the rationality debate? Behavioral and Brain Sciences, 23(5), 645–665. https://doi.org/10.1017/S0140525X00003435
United States v. One Assortment of 89 Firearms, 465 U.S. 354 (1984).
Walton, D. N. (1996). Arguments from ignorance. Pennsylvania State University Press.
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John Balla studies why good thinking is rare — and how to make it abundant. He writes and hosts The Critical Thinking Literacy Channel. Attack on Reason is the series on informal logical fallacies, cognitive biases, and heuristics. Other topics include:
Originally published at https://johnballa546204.substack.com on August 24, 2026.
