Incomplete Evidence




Also Known As: Suppressed Evidence, Cherry Picking, One-Sided Argument

This fallacy occurs when available evidence that would count against a claim is ignored or suppressed. Looked at another way, it occurs when only evidence in support of a claim is selected or “cherry picked.” It has the following form:


Premise 1:  Evidence E is given for claim C.

Premise 2: It is asserted or implied that here is no available evidence A that would significantly count against C (but A is available and is ignored or suppressed).

Conclusion: Therefore, C is true.


Unlike many other fallacies, this fallacy does not arise because the presented premises do not logically support the conclusion. Instead, the error is that the person making the argument fails (intentionally or accidentally) to consider available evidence would count against their conclusion.  The fallacy does its work by conveying the impression that the premises are both true and complete (that salient evidence has not been ignored or suppressed).

There are two factors that must be considered when determining whether the fallacy has been committed.  The first is whether the suppressed/ignored evidence is significant. That some salient information has been left out is not enough to show the fallacy has been committed. For the fallacy to occur, the suppressed/ignored evidence would need to make a meaningful difference in the strength of the argument. If not, the fallacy is not committed. This factor is important for allowing people to create concise arguments without committing this fallacy.

The second is whether the (allegedly) suppressed/ignored evidence was reasonably available to the person committing the fallacy.  If someone is alleged to have “ignored” evidence that they could not reasonably be expected to know, then they would not be committing this fallacy.  Sorting out what a person can reasonably be expected to know can be challenging and thus there can often be reasonable dispute over whether the fallacy was committed.

As a general guide, if the evidence was missed because of carelessness, bias, or lack of reasonable effort, then it would be reasonable to expect the person to be aware of the evidence in question. A person who knowingly suppresses or ignores evidence would be guilty of committing this fallacy in bad faith. There is an entire field of epistemology (the theory of knowledge) devoted to the ethics of belief. One concern of this field is sorting out what obligations people have (if any) in terms of considering evidence for their beliefs. Since this is a matter of considerable debate, I cannot offer a definitive account of what would count as wrongfully ignoring or suppressing evidence.

One form of the Fallacy of Accent, namely quoting out of context, is a type of Incomplete Evidence.


Defense: While, as noted above, there is considerable philosophical controversy over the ethics of belief, the main defense against inflicting or suffering this fallacy is to consider whether relevant and meaningful evidence has been ignored or suppressed. If it has, then the evidence would not warrant accepting the conclusion. As always, this does not entail that the conclusion must be false. It could be true, even if the argument does not support it.


Example #1

“Most philosophers are men. Since Dr. Sarah Shute is a philosopher, Dr. Shute is a man.”


Example #2

“People from the Middle East generally do not speak English fluently. So, I’ll certainly need to get a translator when I interview the Israeli ambassador to the United States.”


Example #3

Steve: “All those gun control laws are unconstitutional.”

Mitt: “Could you be more specific?”

Steve: “Well, here is an example. By law, I can’t bring my pistol to class.”

Mitt: “How is that unconstitutional?”

Steve: “The Second Amendment clearly states that the right of the people to bear arms shall not be infringed. My right to bear my pistol in class is clearly being infringed! So, that law is unconstitutional.”

Mitt: “Maybe you should read the whole amendment and maybe some of the rulings on relevant cases. You are in law school, after all.”


Example #4

David: “Did you read by blog about how the founding fathers were fundamentalist Christians?”

Thomas: “Not yet. Can you sum up your argument?”

David: “Sure. I went to the original texts and found all the references made to Christianity by the founding fathers that match fundamentalist ideas. I found quite a few and they clearly serve as evidence for my thesis. Those liberal atheists are really going to hate me!”

Thomas: “Hmm, that is interesting. But did you consider references they made to Christianity and other things that do not match your fundamentalism?”

David: “Well, no. My thesis is that they held to fundamentalist views. Why would I bother looking for evidence that they were not? I’m sure there isn’t any.”


Example #5

Bill: “There is a war on New Year’s Eve!”

Hilda: “What?”

Bill: “People are saying ‘Happy Holidays!’ That is proof! They don’t want us to say, ‘Happy New Year!”

Hilda: “Who are they?”

Bill: “You know. Them.”

Hilda: “Giant ants?”

Bill: “What?”

Hilda: “People have been saying ‘Happy Holidays’ for years, this is nothing new. Don’t you remember people saying that when you were a kid? You can also Google it, you know.”

Bill” “Do not threaten me with facts. Or giant ants.”

Originally appeared on A Philosopher’s Blog Read More