Is there a name for the logical fallacy of assuming that if one can't personally understand something, it must not be valid?

For example, I've heard people refuting scientific evidence on the grounds that the science behind it is incomprehensible to them. (Even though the science is perfectly comprehensible to scientists.)

And sometimes I notice myself refuting an esoteric philosophical argument on the grounds that since I can't understand it, it can't possibly prove anything.

Is there a formal name for this kind of fallacy? I want to call it the "fallacy of failure to comprehend" but I don't see this used anywhere. Is there another name for it?

In an attempt to tease out what I'm after, I'll give an exaggerated example. TV talk show host Jane is interviewing guest Dick:

"Nothing in the wisdom of the ancient Greeks is relevant to the modern world," says Dick.

"What about the Pythagorean Theorem?" asks Jane.

Dick: "Remind me what that was?"

Jane: "Calculating a diagonal length by taking the square root of the rectangular dimensions squared."

Dick: "I have no idea what 'square root' and 'squared' mean, no doubt because they are too archaic to be of any use to us today."

Hearing this, Jane and the entire viewing audience know it is useless to argue the point. Dick is clearly incapable of comprehending it, as his rebuttal proves. He is not arguing from ignorance, he is demonstrating a personal ignorance. It's not that he doesn't trust the available evidence behind Jane's point, but that he doesn't have enough wit (or vocabulary or education or equanimity or whatever) to even recognize her point. And on that ground he refutes it.

Wouldn't this be considered a logical fallacy of some kind? If so, what would it be called?

  • 1
    maybe the argument from incredulity
    – user3306
    Commented Mar 10, 2013 at 18:10
  • Incredulity can overlap with ignorance, to be sure, but it doesn't assume ignorance. For example, "You can't really expect me to believe that a teapot is orbiting the earth!" is an argument from incredulity, not incomprehension. Whereas "You can't really expect us to believe that all that mathematical gobbledygook proves anything!" is an argument based on a failure to comprehend.
    – Eva
    Commented Mar 10, 2013 at 18:49
  • "I have no idea what 'square root' and 'squared' mean, no doubt because they are too archaic to be of any use to us today." This is not an argument, but plain simple demonstration of ignorance. Commented Mar 11, 2013 at 11:59

2 Answers 2


Haha- yeah, I'm pretty sure the term you want is "ignorance".

This was not a serious answer since I believe you were asking if there were an "official" philosophical term for it and "ignorance" obviously is not it. However, lest this post be considered a waste of good bytes, I will state that I don't believe there actually IS an official term for it because it would not actually be considered a logical fallacy in itself, but rather as someone else said, more like an argument of ignorance. Logical fallacies are where arguments are made which may even appear valid yet are logically unsound. "Nothing about the ancient Greeks is relevant to the modern world." is not in any way, shape or form an actual ARGUMENT as is simply makes a statement of, I suppose we could say, opinion. An argument would have stated some form of reasoning, however unsound it might or might not be. "Nothing about the ancient Greeks is relevant to the modern world BECAUSE..." "...the people of the past were too different from us today for it to relate." or "...because they were truly democratic while America is a republic" or "...anyone who chose to wear togas and believed in diplomacy over warfare is naive."

What you are talking about, when a person is able to make a statement that they believe to be true due to their ignorance of the invalidity of their statement we would call that simply "ignorance". If a person makes that statement and is then made aware of information that is not logically compatible with their statement's validity, yet are of such a strong opinion that they willfully ignore it or discount it... in your example, the "fallacy" only appears once our ignorant opponent of modern Grecian relevance makes the statement that he has likely not heard of "square" and "square root" because they are too archaic to be of use today. He is falsely assuming that 1) the terms are not in common use because he has not personally heard of them and 2) that these terms are not in common usage today because they are so ARCHAIC. The first assumption is not a fallacy, but rather just general stupidity and ignorance... one could even make the argument that since everything we know was once something we were at one time unaware and that since his argument begins by assuming his being unaware of it means it does not exist then his argument is inherently invalid no matter what it ends up being, as things that he is aware of are valid and those he is not are not, yet everything he is aware of is something which he was once unaware of.

The second assumption is the logical fallacy, where he takes a (supposedly) true statement, that these things are not in use today (HOWEVER he got to that) and states that is because they are so archaic... which, I actually just noticed, is what your hypothetical "hard-head" is actually giving as his argument for the Greeks modern irrelevance- that that which is "archaic" is inherently worthless today. Fallacies everywhere; supporting an argument with itself, relating unconnected things in such a way to appear to support ones argument... but sorry, I don't think there's a new one here. Holding onto ones views as being logically sound after having been shown their invalidity is something which one cannot do and BE INVOLVED in a logical discourse at that point. It is not a logical fallacy; in fact it eschews logic altogether.

Hope this helps.

  • In other words, "That's not logical. It's not even illogical." :-)
    – Eva
    Commented Mar 11, 2013 at 4:34
  • Seriously, thank you, everyone, for your answers. I am a little disappointed to learn that there is no polite logic-jargon one can use to soften a critique of someone demonstrating ignorance.
    – Eva
    Commented Mar 11, 2013 at 4:40

It would possibly seem to me to be a very basic form of argument from ignorance; the more traditional version of the argument centers around something "everyone knows" that is presumed inviolate; in other words, making the short circuit that whatever is "generally believed" which has not been proved false must be the truth.

  • --More generally: I suspect a reactionary impulse lurking beneath the ostensible failure-to-comprehend, a 'cunning' stupidity which is equivalent with the pseudo-rational "common" sense of the world, what 'everyone knows'...
    – Joseph Weissman
    Commented Mar 10, 2013 at 18:13
  • "Argument from ignorance" sounds like the perfect name for this, but when I looked it up I discovered that it refers to a bilateral ignorance, an ignorance shared by both parties in a debate. For example, "No one knows what happens after death, therefore our thoughts are eternal" would be an argument from ignorance, yes? Whereas "I don't personally understand the biochemistry of the brain, therefore our thoughts are eternal" shows a unilateral ignorance. That's the kind of fallacy I'm trying to pin down here.
    – Eva
    Commented Mar 10, 2013 at 18:34
  • That just sounds like idealism (though maybe I'm missing something here); I wouldn't classify it as a fallacy per se (though anthropocentrism might have something to do with all this); Nietzsche might number it among humankind's "long errors"...
    – Joseph Weissman
    Commented Mar 10, 2013 at 19:36

Not the answer you're looking for? Browse other questions tagged .