The situation

Let's say, someone is wrong on the internet. She says

The forums on that newspaper article is closed. Apparently the newspaper want to suppress public debate.

I reply:

That's just a suspicion. Just because that's your first thought, it does not mean that's true.

She replies:

What else should be the reason?

Now I am in doubt about whether this person has made a logical argument or not and whether it is rational for me to take the view that the newspaper wants to suppress public debate until more information is available.

No fallacy I know of fits this type of argument

My first impulse is to decline that argument and accuse her of an unlogical argument, because she infers something without considering alternatives (with the justification that she cannot think of any).

I suspect the person used the Availability Heuristic to make the conclusion. But the way by which the conclusion is made does not say anything about whether it's logically sound.

So I tried to think of possible logical fallacies, and none of them seem to fit:

  • Argument from ignorance: (There is no evidence against x. Therefore, x is true). However, her conclusion is due to lack of alternatives fitting equally well to the given evidence, not so much on the lack of contradicting evidence.
  • Argument from incredulity (I can't imagine how x could be true. Therefore, x is false). However, the argument is less about how the person cannot believe a possible explanation, but she comes up with an explanation by herself.
  • Shifting the burden of proof: (If you can't come up with an answer to "what else could be the reason", I am right). This is not applicable, because the person has brought evidence: The closed forum. It's just that she has not brought evidence that her explantation is the only possible. But then again, it's very difficult to prove that in the real world.

Scientists do the same

Moreover, I hesitate because this reminds me of the scientific method, where each theory is only accepted preliminarily until disproven.

In this case, the theory would be that the newspaper wants to stiffle the public debate about the given article. The evidence is that they closed down the online forum. Therefore, I cannot disprove the theory that the newspaper wants to stifle debate about that article, because the evidence does not contradict my theory.

So, the questions are:

  1. Is the argument of the person logically flawed?
  2. Does the argument of the person follow the same methodology as Popper's Falsificationism and is therefore a valid scientific conclusion?
  3. If 1. is true and 2. is true, there must obviously be a criterion which separates a logically flawed conclusion like stated above from a conclusion accepted among scientists. What is that criterion?
  • 3
    This sort of inference is called abduction "a form of logical inference which starts with an observation or set of observations then seeks to find the simplest and most likely explanation for the observations". Yes, it is formally invalid, so a formal fallacy. However, in practical matters formal validity is a wrong standard to apply. To defeat an abductive inference one has to offer an alternative explanation that is at least as plausible as the one disputed. Like, "it could also be that the comments contained too many obscenities".
    – Conifold
    Commented Dec 20, 2018 at 22:55
  • 1
    Abduction was a favoured method of Sherlock Holmes, who would sometimes called in by the police when they had made exactly the mistake you mention, becoming baffled by the crime because they had not seen there were suspects missing from their list.
    – user20253
    Commented Dec 22, 2018 at 11:12
  • 1
    I just want to mention that the line about scientists doing the same is wrong. A theory is not accepted as true because there is nothing better it is accepted because it is rigoursly adequate at explaining. And is not necessarily rejected until it is disproven, it can be rejected when there is a better theory that ecompasses more phenomena (facts).
    – Cell
    Commented Dec 26, 2018 at 17:26
  • @Cell, thank you for your comment. But what exactly do you mean by "rigorously adequate"? Given a controversial science topic, adversaries on both sides will regard "their" theory as "rigorously adequate"
    – akraf
    Commented Jan 2, 2019 at 20:42
  • I think its pretty obvious that in your example "because I can't think of another explanation" is a an hasty claim with no support outside the realm of one's imagination and clearly lacks the rigor in science where scientific hypothesis are exhausted through experimentation for scientists to say "this likely the reason and we can't see any other way it works". Honestly to equate the two is kind of an insult to researchers.
    – Cell
    Commented Jan 2, 2019 at 21:21

6 Answers 6


The forums on that newspaper article is closed. Apparently the newspaper want to suppress public debate.

With these exact words, I'd vote for argument from ignorance and jumping to conclusions. Problem is the word "apparently" which implies a hypothesis instead of a conclusion, which means we have to go Bayesian and consider the probability P(E) of event E="The newspaper wants to suppress public debate".

Now consider the event F="Forums are closed". What does this event say about P(E)? If we accept that E="wanting to suppress public debate" implies F="closing the forums" then it can certainly be argued that P(E) would be higher if F is true, and this would not be a fallacy.

Even if E="wanting to suppress public debate" does not strictly imply F="closing the forums" (for example the forums could be heavily censored or packed full of shills) it would still arguably be a good guess.

Therefore a better wording would be:

Newspapers who close comments forums are more likely to want to suppress public debate than newspapers who keep comment forums open.

However we have no way to know how much more likely. The fallacy lies in taking it for granted that the influence of event F on P(E) is huge, but this is unknown.

For example, the forums might be closed because the unpaid interns in charge of moderation are on depression leave due to epic amounts of trolling.

In order to clear the doubt,

She replies: What else should be the reason?

If this is a rhetorical question, then she's wrong. However if she wants to list other hypothesis and check which is the most likely, then it's a legit question.

Now I am in doubt about whether this person has made a logical argument

No, she took a correct probabilistic reasoning and turned it into an invalid argument by missing the fact that she doesn't know the actual values of the conditional probabilities. Then, you tried to fit her probabilistic reasoning into a TRUE/FALSE binary thinking frame, ie you want to reach a firm conclusion which is not possible in this case due to lack of data.

it is rational for me to take the view that the newspaper wants to suppress public debate until more information is available.

The rational thing to do is to not use hard binary thinking, rather when learning that the forums are closed, simply consider how likely you previously thought this newspaper to be pro-censorship, and update your opinion by raising the likelihood by about a notch.


All that follows from your not being able to find another explanation is - that you cannot find another explanation. There is no valid inference from 'I cannot think of another explanation of X than Y' to 'Y is true'. Y may be your your inference to the best explanation but such explanations are not necessarily true - they are only evidentially the best (simplest, most plausible, maximally consistent with all other evidence). All this, but not necessarily true.

Welcome to PSE !

  • So if you say, my conjecture 1 is true, and at least don't contradict my conjecture 2, what would then be your answer to 3)? Would the argument of the person in the OP qualify as a scientific theory and should therefore be accepted by scientists?
    – akraf
    Commented Dec 21, 2018 at 13:55
  • @akraf. Hello : I was answering the question in the heading. Suppose the truth is that S explains P. How would it follow that T explains P - that you are entitled to claim that T explains P - just because you can't think of another explanation, in particular that S explains P ? The truth is not limited or determined by what we can or can't think of. Not in any standard or straightforward way, or so it seems to me. Best - GLT
    – Geoffrey Thomas
    Commented Dec 21, 2018 at 14:21

There are other reasons why the forum might be closed, and we can check them. Does the newspaper normally close down forums after a certain time? If so, has that time elapsed for that article? Did the discussion get so uncivil that the newspaper shut it down? We can see what was posted shortly before the shutdown. Did discussion just die out before the forum was closed? Again, check the latest posts.

Suppose we have checked these out. The newspaper normally holds forums open longer than that, and there was relatively civil discussion up until the forum was closed. Maybe there's support for the suppression theory, because it came out that the newspaper did it in the past.

It might well come out that the suppression hypothesis is the one that looks most in accordance with the observations. This is the scientific way to do it.

However, how confident are we? Are we likely to have missed other possible reasons? Is it just inherently unlikely? Can we find evidence that it wasn't for suppression? We can have a best-looking theory without having a good-looking theory.

The problem with reasoning, in this case, is not concluding that suppressing debate is the likely reason. The problem is if we are more sure about this than the evidence warrants, or ending the investigation because we've come to a conclusion we like. Scientists tend to keep track of which theories seem reliable and which are shaky. The luminiferous aether theory was recognized as having problems before any better theory came along. Scientists worked with it because it was the best theory they had available, not because they were sure it existed.

  • Your comments about conclusions we like and keeping track of theories helped me, thank you!
    – akraf
    Commented Dec 21, 2018 at 0:16
  • However, I still have a problem when following your first paragraphs: If I check alternative theories, I arrive at the same problem, just with another claim. Previously, the claim was "A is true", now it is "One of A,B,C is true", if I could think of B and C to check. However, I cannot prove that these are the only possible explanations. Therefore, I also cannot conclude that one hypothesis conforms best to my evidence as there might be another, better hypothesis. ...
    – akraf
    Commented Dec 21, 2018 at 0:20
  • ... So is it rational to conclude that one of A,B,C is true? This is question 1 from the OP and the same applies to the other two questions from above, analogously
    – akraf
    Commented Dec 21, 2018 at 0:23
  • @akraf We can never "prove" anything empirical if the standard is to review "everything", this is just the wrong standard. It is rational to accept the hypothesis that conforms best from the available ones. It is also rational to admit that our knowledge is fallible, and open to future revision.
    – Conifold
    Commented Dec 22, 2018 at 1:46
  • Remember that we are typically talking about probabilistic reasoning here, and it is even possible to bound the probability of a hitherto new explanation. I refer to the example of a doctor in my own answer, and it helps here. A doctor can say that they have seen a thousand rashes, 995 caused by eczema (or split among eczema, insects and allergies) and five were undiagnosed. (They can further say text books and studies agree with the break down.) Therefore although they cannot be certain it is A, B, or C they can reasonably initially downplay the unknown explanation case.
    – Josiah
    Commented Dec 24, 2018 at 0:13

You mention the argument from ignorance/silence as something that seems distinct and yet similar. Indeed it is similar, both in nature and in the sorts of things that determine whether it is a good (although typically** still not definitive) argument.

For example, in the argument from silence the strength of the argument is increased as it becomes more likely that the contrary evidence would exist. Similarly this argument is strengthened as it becomes more likely that an alternative explanation would present itself. That's why we trust a qualified dermatologist who says "I can't think of anything else that causes a rash like this" sooner than we'd trust a mechanic saying the same.

An argument from silence is strengthened as contrary evidence is discredited, such as by finding that the only presented evidence is fraudulent. Similarly the modern scientific method includes considering alternative explanations and dismissing them. We generally trust a theory more as more attempts have been made to budge it.

In fact, an argument from silence could be considered a special case of this abductive model of reasoning. It is, at root, a question of the form "What better explanation is there for the lack of evidence against P than the truth of P?"

So, is abductive reasoning a fallacy? Not inherently. It is a whole family of techniques that ranges from weak to strong. But it is indeed true that "Nothing immediately pops to mind" tends to sit at the weak end of the scale.

** It is in fact possible to use this form of argument in a way that is conclusive, so long as all possible explanations or groups of explanations can be enumerated. For example there is a family of chess puzzles called Retrograde Analysis in which it is necessary to work out how what moves could have caused a position.

It works on the same model as the famous Holmes quote "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."


Basically, her agument is that the lack of alternative claims for the evidence means that her claim - "Apparently the newspaper want to suppress public debate"- is true.

  1. She is logically flawed.

"The forums on that newspaper article is closed. Apparently the newspaper want to suppress public debate."

First, this is a faulty generalization: just because a similar case where "Apparently the newspaper want to suppress public debate" has occurred, or it is a possibility to have occurred, and assuming such a situation has occurred before, does not entail that her case is of the same kind.

"Argument from ignorance: (There is no evidence against x. Therefore, x is true). However, her conclusion is due to lack of alternatives fitting equally well to the given evidence, not so much on the lack of contradicting evidence."

Second, Her conclusion must be reanalyzed since there are alternatives fitting equally well to given evidence, such as a possibility of the newspaper having a reason that is anything other than suppressing debate, such as wanting readers to look at other news articles or merely just wanting to close it for no reason.

  1. It does not follow Popper because testing and evidence is what is in question, not the claims.

A lack of counter evidence, that makes a theory false, is not similar to the idea that having a lack of alternative claims, for a single evidence, makes a certain claim true. The former is testing a theory until we find evidence for it be false; the latter is coming up with a claim that fits the evidence, which will absolutely vary and be numerous since one can derive any claim from a single evidence instead of using it to discredit an already proposed claim.

Recap: logically finding counter evidence will discredit a theory; empirical evidence is that which rechecks a theory until such theory has been proven false due to new evidence- inductive reasoning.

Again, the "evidence" is quite circumstantial, and thus unreliable.

If one were to state that the evidence entails her claim, it would be illogical; for what I understand, she is stating the following:

IF A: the "forums on that newspaper article is closed"

THEN B: "the newspaper want to suppress public debate."

It is not a valid scientific conclusion since the singular statement, "The forums on that newspaper article is closed", does not solely propose the idea that the newspaper is suppressing public debate due to multitude of reasons could be the cause of such an occurrence as to why the newspaper closed the forum; in other words, the evidence does not entail to her claim about the newspaper.

Now, if such a statement were proposed in reverse, it would be reasonable:

IF B: "the newspaper want to suppress public debate."

Then A: the "forums on that newspaper article is closed"

As you can see, the former argument is illogical: A does not entail B. But B can entail A.

  1. Again, the criterion involves testing theories with evidence and not about producing claims;in other words, evidence must entail. The logical flawed conclusion is derived from a single general statement that does not point directly to the idea about the newspapers intention behind their actions.

Is it scientific or a logical error to claim something is true because I can't think of another explanation?

Interestingly, this is similar to our ancestors of ancient Greece thinking that giants where the sole reason behind large rocks plummeting earth, when it is actually just a meteor from space. There isn't any other claims that goes with the evidence of a huge crater in the ground, so giants have to be the reason behind huge rocks falling from the sky because they are capable of just throwing it. The claims arise from the individual's ignorance.

TLTR: She is speculating based on occurred events, where events - or evidence in this case - can lead one to think of any claim. Just because you cannot think of a claim to accompany the evidence does not mean a claim does not exist to explain the evidence. Moreover, this is not falsification since she is not testing a theory with evidence, and logically discrediting a theory due to new evidence, but rather she is just speculating because of a single observed statement - a statement that can mean anything.


Here’s a correct conclusion: A explains X. Nothing else but A can explain X. Therefore A is the reason for X.

Here’s an incorrect conclusion: A explains X. I cannot think of anything but A that can explain X. Therefore A is the reason for X.

The difference is that “I cannot think of anything else” is a very weak reason. Any possible other explanation destroys the argument completely. In this case even something weak like “someone controlling the website made a mistake and closed the wrong discussion” is a valid explanation.

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