6 Four of the Worst Arguments in the Word

In logic an argument is a set of statements that present evidence for a conclusion.  By evidence is meant relevant support or justification.  Such evidence gives us reasons to believe that a statement is true.  This is not the same as proof, which is a much stricter concept than evidence. We can have good reasons to believe something based on evidence that falls short of proof.1

Have you encountered anyone who has emphatic opinions but is seldom able to give clear reasons for them?  For many people the fact that they have an opinion is good enough reason to keep it. They don’t want facts, evidence, and logic getting in the way. This does not mean that they cannot have an opinion or that their opinion is false. Most Americans seem to agree with the principle “Everyone has a right to their own opinion.”  Sure, but the right to have an opinion does not man that the opinion is the right one.  It is possible for people to have false beliefs and hold opinions that turn out not to be true.  Indeed, the right to have your own opinion (and not be punished for having it) includes the right to have a false opinion. It does not mean that every belief is true just because someone believes it. Making that mistake is an equivocation on the word “right.”

An argument can be analyzed and evaluated just as a calculation can, though not always with such precision.  Analysis can show whether the evidence given is really relevant and sufficient to support the conclusion. The study of the analysis and evaluation of arguments is Logic.  This short introduction involves Informal Logic which typically focuses on arguments in real life. One area of Informal Logic is the study of Fallacies: arguments that appear to give strong evidence but are logically flawed.  Some fallacies are so popular that they have their own categories. I think that you may recognize some of these from your own experience.  These fallacies come in many variations and it sometimes takes careful analysis to find them out.  I’ll present five common fallacies and some ways to counter them.  My hope is that you will look for ways that these deceptive arguments affect your thought and life, so that you may avoid such deceptions (especially if you are prone to make any such yourself).  There are many useful materials in print and on the web about these fallacies and many others.  I hope that you will research these further.  This document is meant to introduce you to these ideas if you don’t know them or to remind you of them if you do.

  1. Post Hoc Ergo Prompter Hoc

Event A occurred, then event B occurred. Therefore, A caused B.

This fallacy does great harm in the world because the attribution of cause is how we confer responsibility.  The Latin phrase means; “This after that, therefore this because of that.”  Another way to say this is; “A then B, therefore A causes B.”  Every causal belief or statement is an inference.  As David Hume (1711-1776) noted, we do not observe the causation.  What we observe are correlated events.  From their relation in time, space, frequency, etc. we infer that the correlated occurrences are causally related.  Our observations do allow us to make cogent causal inferences as we must to get around in the world.  Yet we can also make completely uncogent causal inferences from observation and it can be hard for us to tell the difference.  Here is a common, though not trivial, example;

You have had a cold for several days. Your friend comes down with a cold.  He says; “Well, you gave me your cold.” Let’s analyze this.


A happened=You had a cold days ago (and still do).

B happened=He has a cold today.

His causal inference=your cold caused his cold (“you gave it to me”).


So what’s fallacious about this?  Just that the evidence given is not strong enough to support the conclusion (inference).  Two similar events happened in succession in time.  It simply does not follow from that alone that they are causally related as claimed.  It may be that they are causally related, but there are three other possibilities which have not been ruled out.  Without additional evidence they are all as strong conclusions as the causal inference.

Third Cause: It may be that both of you caught the cold (i.e. transmitted the virus) from another person.  Other causal factors are always possibilities that should be check.  Often we find that a causal relation is far more complex than we realized (involving many interwoven causes and effects).

Reverse Cause: It may be that there is a causal relation between your and your friend’s colds,

only it goes the other way.  Perhaps you caught the cold from her, but it just took longer for her symptoms to develop.  This is instructive because it shows how we often rely on appearances for our inferences, whereas the underlying cause-effect may be very different.

Coincidence: It may be that you caught your cold from another person and you friend caught hers from yet another person all together.  In that case there is no causal relation between your cold and hers.  They may even be completely different viruses.  It is natural to assume that similarity in appearances and proximity in time and space points to causation. That’s not enough evidence.

To be clear – I am not saying that it is fallacious to make causal inferences.  I am saying that we should test our causal inferences in order to improve the evidence.  Just being aware of the potential for fallacious causal inference, and knowing what to look for (i.e. the above alternate hypotheses) can be enough to temper bad choices based on uncogent inferences.


  1. Tu Quoque

A makes statement P as a allegation.

A is also guilty of statement P. Therefore, statement P is false (or the allegation is dismissed).

I am betting that you have direct experience with this fallacy.  It is so pervasive and effective, you may not even agree with me that it is fallacious.  I hope to persuade you otherwise.  Tu Quoque (two quo quay) is Latin for “You Too.”  The general form is to take any criticism, apply that same criticism to the person who made it, and assert the turn-around as a refutation of the criticism.  This is very popular in domestic life:

Person A: Gosh, you just cut that person off in the other lane. That’s dangerous. Person B: You’re one to talk.  You got a speeding ticket just last month.

Recognize the technique?  It is used in all sorts of issues and takes many forms.  Consider some common Tu Quoque retorts (admittedly without context to determine whether they are fallacious):

  • Why blame me?  Haven’t you ever made a mistake?
  • Are you perfect?  If not, get off my case.
  • You do the same thing.
  • That’s amusing coming from you.
  • And what about you….?
  • You are equally to blame.

Tu Quoque often appears to be an appeal to fairness or an objection to hypocrisy.  Look closer through an analysis of the driver’s argument above:

1: Statement A = Cutting off the driver was dangerous.

2: Statement B = You got a speeding ticket (i.e. you drive dangerously). 3: Conclusion  = Cutting off the other driver was not dangerous.

The conclusion cannot follow from those premises.  The big point is this: even if your critic is a guilty of the same thing and a totally hypocrite, it does not follow that their statement is false.  It may well be that you are both dangerous drivers.

Do you recognize this fallacious tactic?  Some people make an art of it in domestic life.  They can dodge just about any criticism by turning the tables on their critics.

I have relatives whose political reasoning is just about summed in toto up by Tu Quoque.  Any and every concern about their preferred party and positions can be deflected by retorting:

The other side does the same thing!

I am not exaggerating.  That exact sentence is automatically tossed out at any political critique whatever (except when point favors their party and positions).  As a child I first recognized the repetition of the technique.  Later I found out about it’s logical attributes.  What I came to realize is that no matter what the “other side” does or is, it does not logically or morally justify what happens on this side.

Here is another way to see this point: when someone uses a Tu Quoque they are making an accusation.  You or they did X and X is just as wrong.  Notice what is implicit in that accusation; that “X is wrong.”  If it were not there would be no force in making the accusation.  Consider what is lost in this.  If “the other side is just as bad” then it is “just as bad as my side.”  That is to say; “my side is bad.”  Or to put more clearly, the original allegation is accurate.

In a way the Tu Quoque is worse than fallacious, it is a way to derail the addressing of flaws and falsehoods.  It is a mechanism of self-denial.  Tu Quoque acts as a sort of pseudo-logical blackmail.  You cannot criticize me because then I will expose your flaws.  The fact that some people actually accept Tu Quoque as a compelling argument shows how confused our reasoning and social discourse can become.

Since Tu Quoque operates by seeming to dismiss the right to a claim, we had better address a potential conflation with some well known moral maxims.  We all know the Golden Rule; Do to others as you would have them do to you and Jesus’ maxim;

“And why behold you the mote that is in your brother’s eye, but consider not the beam that is in your own eye?”2

Matthew 7:3. American Standard Version. Cf. Luke 6:42

Neither of these is counseling us to commit Tu Quoque.  The Golden Rule advises us to see the similarities between our own subjective experience and the experience of others.  The point is to identify and empathize with others, not to excuse our own faults based on a judgement of someone else.

Jesus is not urging us to ignore our faults.  He is exhorting us to recognize our weaknesses and improve on them.  Indeed, both are indicating and warning against a sort of inverted Tu Quoque which works like this: focus on the faults of others and you can all the easier ignore your own. Does that sound at all familiar from your experience?  This really take us to an important issue. Consider how groups of people cast each other as negative.  Such as high school cliques and communities with racial divisions.  By promoting a shared image of the other as flawed and negative we can gain a sense of belonging with our own group.  You may have experienced  this yourself. If not, read “Queen Bees and Wannabes” by Rosalind Wiseman and see “Mean Girls” a movie loosely based on Wiseman’s book.   The premise is that we can create a sort of social cohesion by sharing an enemy.  My hypothesis is that this operates by giving the group a mechanism to conceal or ignore individual faults, thus strengthening the social bond.

My theorizing can wait until another time (though I’d love to hear from you about these ideas). My point here is that concealing ones own faults (the beam in my eye) by exposing the faults of others (the mote in their eye) is just how Tu Quoque works.  We cannot regard advise to look more closely and honestly at ourselves as providing any justification for Tu Quoque.

Research more – Fallacy Files: Tu Quoque

  1. ad Ignoratum

There is no evidence that statement P is false Therefore statement P is true.

On the face of it seems that no one could think that the lack of knowledge about something counts as evidence for it.  You may then be surprised at how commonly and successfully variations of this fallacy occurs.  The Latin means “To ignorance” as in “An appeal to ignorance.”  We can find variations on this fallacy where someone cites the absence of a cognitive state or of evidence of any form.  The form I a most attuned to goes something like this;

I cannot think of any other explanation; therefore statement P (i.e. the proposed explanation) must be true.

This can be phrased as a question;

What other explanation is there?

This and its many variations come down to the assumption that if I or we can only think of one explanation for some phenomenon, then that one explanation must be correct.

If this were the case, then the lower our creativity, the greater our knowledge of the world.  That is not so.  There are always alternate possible explanations for every phenomenon.  Our inability to discern them is a feature of our mental character, not a feature of the phenomena at issue.

A powerful combination is to combine ad Ignoratum with the suppression of alternate ideas. This can happen in a relationship, in a culture, and through history.  Galileo (1564-1642) published his arguments for the Copernican theory that the earth orbits the sun,  his theory of the tides.  Up to then the authorities had argued that there was no other explanation for the motion of sun and other celestial bodies other than that the earth sat in the center with the others revolving about us.  When systematic a creative thinkers found evidence for the alternate explanation, they were burned , as was Bruno, or arrested and forced to recant, as with Galileo.  In other words, the received doctrine must be true because we cannot conceive of any alternative, and if anyone does conceive of another alternative they will be suppressed.  Please note that the Suppressed

Evidence is separate fallacy from the ad Ignoratum.  I just pointing out how effective these can be when used together.

Variations of ad Ignoratum include:

Incredulity: I cannot imagine not-P; therefore P is true.

Personal knowledge: I’ve never heard of P; therefore P is false.

Conspiracy: The lack of evidence for P demonstrates that it has been hidden from us.

Absence of Evidence: The lack of evidence for P demonstrates that P is false.

Here is an important distinction.  The lack of evidence for an idea does show one thing: that there is no logical support for believing that it is true.  It is also that case that lack of evidence is not logical support that it is false.  Lack of evidence only means that we do not know and that the alternatives remain open.

One notable exception: in US law there is a presumption of innocence.  The burden of proof falls on the accuser (the State) and the defendant is not required to prove their innocence.  However, we must be careful of the word meanings in this case.  Legally innocent means that the person is found not guilty be reasonable doubt.  Factually innocent means that they really did not do the crime.  People who are not factually innocent can be found legally innocent because of the insufficiently of evidence which advances reasonable doubt.  Presumption of innocence would be an ad Ignoratum only if it meant “Presumption of factual innocence.”  It does not.  The innocence involved is legal innocence.

  1. ad Verecundiam/ad Hominem

Source A says that statement p is true.

Source A is a respectable person. Therefore, p is true. or

Source A says that statement p is true. Source A is a flawed person.

Therefore, statement p is false


The Latin phrases mean “to respect” and “to the person.”  More fully “Appeal to respect” and “Appeal to the person.”  I include these together because they are complementaries of one another.  The first proceeds as if we should accept as true statements that are made by people whom we like or admire.  The second proceeds as if we should reject as false statements that are made by people whom we dislike and despise.

The bottom line from a logical point of view is this: wonderful and smart people can get it wrong; horrible and stupid people can get it right.  There just is no logical relations between the character of an individual and the truth-value of the statements that they make.  To judge otherwise is to presume grace or guilt by association.

The situation is far more complex than this, however, because matters of trust and expertise enter in.  We certainly should consider such factors in our judgements.  To do so, however, is to engage other forms of evidence and not just the character of the person who makes the statement. Let’s consider some such cases where judgement about the individual may count as evidence for or against their statements.

Trust: We may well believe what a person says just because we trust them.  This is not a fallacy. It is not a case of ad Verecundiam.  Reasonable trust is based on what we know about someone including their track record of past statements.  It is foolish to continue to trust someone who lies to us repeatedly.  When someone shows themselves to be trustworthy, then we have reason to give privilege to their statements.  Yet please note that we are not taking their statements as true simply because we feel trust.  We are accumulating the evidence for trusting the person as evidence for the person’s statements.  Moreover, it would be odd to accept as true everything that the person said even if they are trustworthy.  This is because some statements cannot depend for their truth on trustworthiness.  If such a person made metaphysical, or religious, or predicative claims, trust would not be enough.  Think of the person who you most admire and trust in the world.  Now suppose that they told you what they thought the world would be like fifty years from now. Surely you would listen and consider what they said, but would it be reasonable to maintain that their thoughts must be true because you have so much trust in them?  Relevance and scope matter a great deal.

Even trust based on your gut feel can be reasonable.  Again, in such a case it is not the feeling of trust along, but also your confidence in your intuition.  That is something that you gain from experience.  Intuitive trust, gut feel, involves a body of evidence beyond your feelings about the other person.

The situation with distrust is similar.  Some people show themselves untrustworthy.  It is foolishness to take their statements on trust.  But why is that?  Is it because you feel distrust for them? Or is it that you have reason to distrust them, such as their history of lying.  Just as with trust, our reasons for distrust become part of the evidence for doubting a claim.  Rejecting a statement based on reasonable distrust is not ad Hominem.  Neither is it merely a rejection based on judgement of character.

Expertise: We do and should take experts at their word on matters relevant to their expertise. Still, someone does not becomes an expert merely because we admire them. They become experts by demonstrating their knowledge, keeping their expert opinion to their area of expertise, and by relying on evidence for their statements.  When our physician tells that we need a kind of treatment it is reasonable to accept that (though the greater the consequences the better the case for seeking a second opinion).  But it is not enough that we like and admire someone to make them our primary physician.  The physician is an expert because they went to medical school, and have years of experience, and studied the literature on the condition, and interpreted the results of the right kinds of tests.  Taken together this body of evidence gives confidence in the physicians judgement.  Reliance on relevant expertise is not a case of ad Verecundiam.

What then is the issue with ad Verecundiam and ad Hominem arguments.  It is when the sole or main evidence for a statement is based on a judgement of the person’s character.  Suppose that P is a factual statement.3  Say for instance, “The economy is showing signs of improvement” or “Mobile phone safety has not been sufficiently tested.” Would any of the following count as sufficient evidence for that statement?

He is a nice guy,…

She is beautiful,…

I like his poise,…

She is well-liked,…

He inspired confidence,…

She is so charismatic,…

His sense of humor really gets to me,…

She is an amazing singer,…

He is world famous,…

She is one of the worlds wealthiest people,…

A proud American,…

…therefore statement P is true

Would any of the following count as sufficient evidence against that statement?

What a jerk,…

Not attractive,…

Really weird,…

Nobody likes her,…


He is a criminal,…

She belongs to the other political party,…

What a has been,…

Environmentalist whackjob,..

Conservative wingnut,…



…therefore statement P is false

Am I exaggerating here?  Not at all.  Talk radio, talk TV, blogs, political campaigns, as well as the full range of our social interactions reveal a vastly longer list of praise and condemnations that speak to the character of the person making the statement with no relevant evidence for or against the statement itself.

Please note that I am not saying that logical error of an ad Verecundiam is that it gives praise or that an ad Hominem is mean spirited.  The logical error, the fallacy, is that the praise or condemnation are not relevant to the truth of the conclusion.  It just does not follow that “The last ten years were the warmest on record” because the man who said so has nice teeth.  It does not follow that the witness who turns states evidence and testifies against the crime boss is making false statement just because he himself is a convicted criminal.  I am sure that you get this. But from all indications, people still give credence to or outright reject factual statements based on unrelated personal characteristics.  The point is, step away from the situation mentally. Imagine the statement presented by someone else.  Look for the reasons and evidence that belong to the statement.

Argument Clinic http://www.youtube.com/watch?v=kQFKtI6gn9Y


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