Someone says:

During the time of the dinosaurs CO2 levels were 9000 ppm. We're at 400. Nothing died back then either. Quite the opposite. Life was absolutely gigantic, even the plants were huge.

In response I ask for the person's source. Their response:

Google it. I'm not going to do your homework for you.

It's a ridiculous response. But is this a form of fallacy? Is there a name for this?

  • 2
    Not an argument, so not a fallacy. Could be called deflective, or just being a jerk. May 1, 2019 at 6:20
  • 2
    It could be an evasive rhetorical tactic, but much depends on the context of the discussion. Such as whether the sides can be expected to do background research before entering it (asking for a source can itself be a form of evasion, by stalling), and whether the information is indeed common, and can be easily found by a Google search. In this case it is, but the 9000ppm is exaggerated, the usual estimates are 2-3000ppm, and the (high) speed of the rise is a separate concern, in addition to the levels themselves.
    – Conifold
    May 1, 2019 at 6:58
  • "The Earth increases mass by 1.3 E 15 kg per year...The surface gravitational force increases, thus animals have become smaller over the last 150 million years." So they were larger because the gravitational force was so low then. But they were also dumber because they weren't getting enough oxygen to their brain-cells. Likewise the creepy skin and other physical features. researchgate.net/post/… Your cited OP failed to take all factors into consideration, perhaps intentionally trying to promote acceptance CO2. (Propaganda).
    – Bread
    May 1, 2019 at 10:24
  • 2
    In the world of engineering we call this RTFM (read the manual) people asking questions deemed passe, are refered to the technical manual so that they can learn for themselves. Being told to RTFM is a not so polite way of telling someone that they should already know the answer.
    – Richard
    May 1, 2019 at 10:35

3 Answers 3


This is called shifting (or shirking) the burden of proof. The "burden of proof" is the responsibility of someone making a controversial claim to support that claim. It is not a fallacy because it is not an argument. You might describe instead as an "illegitimate rhetorical strategy."

The counter is as follows:

Don't try to shift the burden of proof. You made the claim, so it's your responsibility to demonstrate that it's properly sourced.

As mentioned in the comments, however, there is also an implicit argument at work here, "I'm right until proven wrong," which is really just a variant of appeal to ignorance ("this claim is true because we don't know it to be false").

  • I think this is almost right. Simply not backing up one's claim doesn't really suffice for a qualification of shifting the burden; it is required that one would take the position that until/unless his opposition "does the homework", he should be considered right by default (that is, shifting the burden does actually require an argument... an argument that you're right until proven wrong). Your source agrees: "a proposition is assumed to be true because it has not yet been proved false"
    – H Walters
    May 2, 2019 at 17:11
  • @HWalters Edited to address May 2, 2019 at 17:25
  • Great answer I think this is the one
    – codemon
    May 2, 2019 at 17:54

Welcome codemon. I recognise the argumentative manoeuvre you describe. It is not a fallacy since there is no strict error in reasoning (as e.g. in 'If p then q; q; therefore p - the fallacy of affirming the consequent) but it is intellectually sub-standard.

It is close to the argumentum ad verecundiam, appeal to authority. Though I don't agree that the appeal to authority is necessarily fallacious or in any other way objectionable since the authority appealed to may be as reliable at one can get in the present state of knowledge. Whatever else it may be, it is not fallacious to appeal to Einstein as a relevant authority when I claim that E = MC-squared.

In contrast, it is a dubious procedure when I say something such as:

Google it. I'm not going to do your homework for you.

Two things are wrong : (1) Google is not an authority in the way in which an Ivy League paleontologist is [unproved authority]; and (2) precisely where in Google am I to find the most reliable information [vague appeal]? (1) and (2) combine in what one might term a vague appeal to unproved authority. I'm sure there's a better label but this might serve for the present.


By not providing the requested sources and insulting the requester by claiming it is the requester's own "homework" to get those sources, the arguer is making it difficult to understand the assertion that has been made. This may be a form of proof by intimidation.

Bo Bennett describes this as:

Making an argument purposely difficult to understand in an attempt to intimidate your audience into accepting it, or accepting an argument without evidence or being intimidated to question the authority or a priori assumptions of the one making the argument.

Bennett, B. "Proof by Intimidation" Retrieved on May 1, 2019 from *Logically Fallacious at https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/144/Proof-by-Intimidation

  • Something is a bit fishy with exploring a fallacy that someone "may be" committing.
    – H Walters
    May 1, 2019 at 14:36
  • @HWalters The reason for the "may be" is that these are informal fallacies. Were they formal fallacies there would be no ambiguity. Software could mark where the mistake occurred. There may be situations where the behavior is not fallacious because it is not deceptive nor an error of reasoning. May 1, 2019 at 16:13
  • Doesn't this type of assignment of a fallacy itself become an appeal to motive fallacy? Especially if there are not only situations where this fallacy may not be committed, but those situations are very reasonable? My point has nothing to do with whether this is an informal fallacy or a formal fallacy; it has to do with the assignment of a fallacy due to some imagined error the person might have committed going against the grain of the principle of charity. Logical fallacies should be tools to help you find flaws in arguments, not means of finding sticks to beat your opponent with.
    – H Walters
    May 1, 2019 at 17:05
  • ...FYI, I'm seeing this unevident attribution: "an attempt to intimidate your audience" ...being assigned as the motive behind the anonymous third party opposition to the OP, and I'm a bit unconvinced this attribution is justified. That's what I find fishy, not whether it leads to an informal fallacy versus a formal one.
    – H Walters
    May 1, 2019 at 17:11

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