Tag Archive | Ad hominem

Project Logicality | Notes on Common Fallacies & the Fallacist’s Fallacy

Identifying and labeling logical fallacies when they are used as argument strategies is useful – It weakens the rhetorical effect of the labeled argument, possibly even disqualifying it as viable support for a position.

But common fallacies can be used not only to legitimately point out truly inductively weak, logically invalid, or otherwise unpersuasive arguments, but may be overextended as well – they may be misapplied to label sound, cogent, and persuasive arguments as fallacies if and when this is not the case.

The appeal to authority:

This is often used to dismiss a position as merely an argument from authority, if and when it is actually an argument by authority – that the claimed credentials and qualifications of the authority are both true and relevant to the matter discussed, and the authority appealed to has a genuine basis for making their statements.


“Oh, that’s just something that those Establishment archaeologists say to hide the Truth about the Mayan pyramids!”

Incorrect cause:

This can often be used to deny an actual causative correlation that has been shown real, claiming even then that “correlation is not causation,” and invoking a more complex causative relation than needed when the evidence may well point to the simpler relation that A causes B.


“Actually, the warming of the climate is not caused by human industrial pollution, it’s really just a natural cycle that correlates instead with the warming of Mars – and cow farts!”

Ad hominem:

This can be used to argue that the critic of an idea is attacking the proponent of an idea rather than the idea itself – note that an insult, by itself, is not an ad hominem. – it only becomes that when the insult is used as a reason that the one insulted is wrong without substantially addressing the argument itself. An ad hominem is not always a fallacy and can also be used in a legitimate way, as in pointing out a real and relevant conflict of interest or bias in the subject.


“You just say that because you’ve closed your mind to the very possibility of the unconventional.”

“I don’t trust anything you say…you’re in the pay of those well-funded liberal environmental lobbyists.”

“Scientists are arrogant for claiming they know anything.”

Reductio ad absurdum:

Like some other fallacies, this may be used as part of an inductively strong argument or logically valid one and is often used in formal logical proofs. It becomes a fallacy, a false reductio ad absurdum, and a straw man(see below) when used to argue the silliness of a position without using the actual, original line of reasoning in the argument.

Straw man:

This one is easy to commit, and easy to overextend when applied to a legitimate critique of one’s position using the premises and logic actually involved in the original argument. To avoid this, it is necessary to do whatever is required to understand an opponent’s argument and interpret it as charitably as possible, without over-generously ignoring non sequiturs and inconsistencies, or being too proud to ask for clarifications.

To overplay this fallacy and falsely accuse your opponent of a straw man is to commit one yourself through misunderstanding the counterargument given.

An example of both a false reductio ad absurdum and a common straw man:

“If you don’t believe in psychic powers, then you must also not believe in dark energy and dark matter, so 90% of the universe must not exist, because you haven’t seen those either!”

Special pleading:

This form of reasoning is not itself innately fallacious, and can be a perfectly good logical strategy for constructing hypotheses for testing. The fallacy comes when it is used to dismiss fair criticism of an idea or used in an ad hoc manner to patch together a set of hypotheses in an overly limited fashion and render them untestable – neither falsifiable nor meaningfully verifiable. It is also over-employed when used to criticize a valid or strong argument as being ad hoc, when in fact the argument’s premises and assumptions are supported through prior evidence, arguments, or observations and the reasoning is not overly baroque in structure.


“Psi is real, and has been successfully replicated, but skeptical readers of journals these studies are published in use an unconscious, retroactive, and unobservable psychokinesis that reaches through time and causes the successful replications to fail.”

“The big bang model of cosmology can’t possibly be viable…it’s got too many patches like fairy-tale dark matter, undetectable dark energy, and imaginary inflation propping it up from falsification by protecting it from the data.”

The Fallacist’s fallacy…

…which is to argue that because an argument is invalid or weak that the argument’s conclusion is therefore false.

This shows a misunderstanding of the relationship between the truth value of the conclusion and the nature of validity or strength.

Deductive validity means that if the premises are true then the conclusion follows automatically – There is no valid logical argument in which the premises can be true and the conclusion false, because the chain of reasoning follows with certainty, but it is possible for an argument to be fallacious and still have a true conclusion – it just doesn’t follow from the reasoning, requiring a better argument for one’s position.

A conclusion can be false, even with true premises, and an argument therefore not follow, but not following from the premises does not imply the falsehood of the conclusion, only that the argument itself is not cogent, is unpersuasive, and cannot be used to support that position.

Arguments BTW, cannot themselves be true or false, only the individual statements making them up.

(Updated as of 2017.06.06)

Logical Fallacies — Crimes of Relevance

One of the most common ways for arguments to go astray is to make an appeal to irrelevant reasons to support the main claim of an argument, or for complex arguments, the resolution of a case.

Many variations of such appeals are similar to  arguments from authority, in that the authority is not necessarily a person or a direct statement made by same, in or out of context, but a quality attached to an idea, a product, alleged service, protocol, or treatment.

There are several such appeals to evidence which isn’t.

A few are shown below:

  • The appeal to tradition/antiquity — This fallacy lies in inferring that something is true, good, healthy, or works, because it has been in use for a long time, when it’s longevity could simply be the result of social or psychological inertia, or just plain stupidity, and not any real truth, virtues, efficacy, safety, or usefulness of the claim itself. — “But we’ve always held human sacrifices to He Who Nibbles Annoyingly at this time of year to help the crops grow…Why stop now?”
  • The appeal to the new/exotic — Speciously inferring that a thing is good, useful, effective, or to be believed because of some perceived unusual or novel quality, regardless of the actual truth of the claims made for it or other relevant quality of the thing. — “This sweater costs a king’s ransom, but is well worth it, for it was knitted from the wool of Alpine mountain goats fed on imported lichens and flora harvested from a boiling subterranean Antarctic lake by trained eunuchs.”
  • The appeal to sympathy — This is inferring that a claim is to be believed because those making it are deserving of our pity, sympathy, mercy, or are unjustly treated, when such an inference has no relation to the claim being offered — “Hey, this guy’s gotten short shrift in business for years, so let’s consult him on all of our important foreign policy decisions.”
  • The appeal to popularity — This fallacy lies in asserting that something is to be believed because it is widely accepted, when it is easily the case that 7 billion of anybody can indeed be wrong. Indeed, everyone in the universe could believe Azathoth and the Other Gods to be real when that simply would not be the case. — This fallacy, along with appeals to celebrity, is one of the most common used in modern advertising. It is often coupled with the appeal to tradition in some arguments, but is pure poison no matter how it’s used.
  • Appeal to unconventionality/antiauthority — A variation of the argument from authority or perhaps a positive ad hominem, in which the claimant’s virtue is perceived to come from opposition to a tyrannical and dogmatic establishment. Indeed, it’s the claimant’s lack of expertise and allegedly revolutionary mindset that is their main claim to authority. — But those matters requiring real expertise are what they are — revolutionary sentiment and bold words do not make a science, art, or good policy.

Those using these fallacies to promote their claims still must bear the burden of proof if they wish to be taken seriously by those doing genuine research work, or not. And if they wish to do so, the first thing to be done is to use evidence for their claims that actually bear on the issues they raise, to avoid these crimes of relevance, for science answers to a higher authority than any one researcher — reality — and while you can fool individual scientists, reality is not so easily fooled, and the truth will come out no matter how facile the argument against it.

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Project Logicality | The Ad Hominem Argument


Let’s face it, nobody likes to be insulted, but this very thing may be used as a form of argument in more or less subtle ways, a logical fallacy of irrelevance known by the Latin, because yours truly feels like being a pedant, the Argumentum ad Hominem, or the Argument to the Person.

This tactic of argumentation is the counterpoint to the Argument from Authority, a sort of polar opposite to it on the spectrum of genetic fallacies – arguments that focus on the source of a claim rather than valid logic or evidence – and like it attempts to call attention to real or imagined characteristics or origin of the subject in order to sidestep the argument being made, in this case those that are negative or unfavorable.

A special case of this is a subset called Poisoning the Well, also referred to as the Circumstantial ad Hominem, made even before the opponent makes his argument. This form associates the target with someone or something that is widely regarded as unpleasant or evil, such as implying or stating a connection with, for example, Nazis, terrorists, or an infamous serial killer.

The name of this subset probably derives from medieval Europe, when rumors abounded during outbreaks of plague that Jews were causing Christians to die from the epidemic by poisoning the local well-water, since the real vectors of the plague were unknown at the time. This differs from the usual form in that it can be made against both a person and an idea or belief.

In that hideous little abomination of a movie, Expelled, there was much use of this fallacy in the association of evolution and science in general with the Holocaust and the Nazis in particular.

The most common and least subtle form of this argument, used by the unimaginative, is the use of plain and simple verbal abuse to call attention to perceived (real or imaginary) shortcomings as a cheap way to dismiss an argument by dismissing the person making it.

“Your argument is wrong because you’re a known religious fundamentalist.”


“I don’t have to listen to you because you’re one of those Godless atheists.”

…or my favorite,

“I don’t have to provide any references for what I said. You should just accept it as I said it, or you are an obstinate fool for questioning something so self-evidently true.”

Often used is an alleged conflict of interest, bias, or personal prejudice, the Bias ad Hominem, indicating that the one this is used on is untrustworthy as an impartial source, or as is often the case of an American politician accusing his opponent of being a socialist or a fascist even when these claims are not only irrelevant but false.

Another is when critics of the modern anti-vaccination movement are implicated as paid shills in the pocket of the ‘Big Pharma’ conspiracy, and whose statements therefore must be taken with evil intent in mind.

Another is when mainstream scientists are accused of being afraid for their funding, careers, alleged political agendas, and reputations and so ignore or hide ‘the truth’ of the paranormal or global cooling. These last two, by the way, are also referred to as an argument from conspiracy, or an appeal to motive, another version of the bias ad hominem.

But the Ad Hominem argument is not always a fallacy, and in the proper use it may be a valid and effective form of argument when it is used to promote the goal of critical discussion rather than to obstruct it.

For example, a reasonable use is in pointing out a likely conflict of interest regarding the personal testimony of a claimant when the subject’s questionable background, credibility and circumstances are also true, relevant, and kept in their proper context — such as a disgruntled ex-gang member testifying in a criminal case when he has been given leniency or other favors for his testimony.

And this fallacy is more complex than one might think…

Less commonly known, and just as poisonous to an argument, is the positive ad hominem, which uses the same sort of reasoning, substituting alleged personal attributes, associations, or circumstances for relevant evidence in an argument, but this time uses positive traits, such as sincerity, kindness, or piety, though any virtuous trait will do, and here it shades into an argument from authority/appeal to virtue.

Tf. Tk. Tts.

(Last Updated 2017.06.06)