Learn Something?
Buy The Amateur Logician a Cup of Coffee!
Support the Mission to Revive Logic?
Buy The Amateur Logician a Cup of Coffee!
This tutorial is free; however, it took effort, time, and money to put together. I would greatly appreciate any contributions to keep this website project running and expanding. Thank you!
— George Wick
The Amateur Logician Tutorial:
An Invitation | Arguments | Evaluating Arguments | Laws of Thought | Ontology & Logic | Concepts, Signs, & Names | Categorical Propositions | Negations & Complements | Distribution | Euler’s Circles & Venn Diagrams | Predicables | Categories | Definitions | Square of Opposition | Equivalent “Immediate Inference” | Traditional “Immediate Inference” | Informal “Immediate Inference” | Categorical Syllogism | Syllogisms & Venn Diagrams | Moods & Figures of Syllogisms | Polysyllogisms & the Sorites | Enthymemes | Compound Propositions | Conditional Propositions & Conditional Syllogisms | Conditional Contrapositions, Reductions, & Biconditionals | Conjunctions, Disjunctions, & Disjunctive Syllogisms | Dilemmas | Modal Propositions | Reductio ad Absurdum Arguments | Deduction & Induction | Inductive Abstraction | Inductive Syllogisms | Mill’s Inductive Methods | Science & Hypothesis | Formal Fallacies | Testimony & Unsound Authority | Informal Fallacies & Language | Diversion & Relevancy Fallacies | Presumption Fallacies | Causal & Inductive Fallacies
<— Click on a topic!
Testimony & Unsound Authority
Testimony
– Learning is most often a “leap of faith.”
– Authority
– Radical Skepticism
– Evaluating Testimony
– History
Appealing to Authority
– Unsound Authority
– Argumentum ad Verecundiam
– Argumentum ad Populum
Learning is most often a “leap of faith.”
Here the term is used in a technical sense, as faith involves a trust in authorities or testimonial evidence. Natural faith is obviously indispensable for everyone, no matter how smart, because we must largely operate on it. This is how we learn about the world around us. It is how we learn, for example, history. As social animals, we depend upon the communities we belong to. It is how we learn about ourselves, as well. It is via testimony that you know where and when you were born.
Scientists, too, depend upon the work of other scientists. It is entirely rational that they do so, not irrational. No one scientist can verify every single experiment. True enough, an individual must learn how to navigate these waters of testimony, as supposedly good authorities can be bad and some of the waters are filled with highly contradictory theories (and some areas of thought, especially outside of the so-called “hard” sciences, are saturated with bad thinking!). Part of navigating well comes from developing skills in logic and critical thinking on your own. Yet, our intellectual dependence will and must remain.
Even so, we must avoid excessive credulity. Not every statement somebody utters is accurate. People are often mistaken on what they believe. They also don’t invariably tell the truth. People lie and mislead. Though rational as human beings, all of us are fallible and sinful. And so-called authorities can be wrong or corrupt. However, we must additionally avoid excessive incredulity. If we don’t trust any testimonial evidence whatsoever, then we’ve entered into a radical skepticism. We then couldn’t be sure where or when anybody was born. We couldn’t trust if we could “really” communicate with anybody using a language like English (which we learnt via others).
Testimonial evidence is both useful and necessary in order to live a good life and to have knowledge. Sometimes people claim that any “argument from authority” is fallacious. That’s simply not true! An argument from authority can be reasonable or not, depending on the particulars at hand.
This is not only a matter of authority, it’s a matter of any testimony.
Consider this example… An acquaintance of yours claims to have seen a UFO the other day. How should you evaluate this claim?
First, judge the trustworthiness of this person.
Is he usually honest?
Second, judge the person’s character more broadly.
Good memory? Eyesight? Careful in making conclusions? Etc.
Third, any witnesses?
Other things being equal, the greater the number of witnesses and the greater diversity among those witnesses, the likelihood goes up.
(Note that while this third question may increase the likelihood that the original claim is true, sometimes this may be totally unreasonable, and possibly unjust, to demand a witness before you accept a particular testimony!)
Fourth, any other corroborating evidence?
Perhaps the acquaintance, for example, shows you a picture.
History depends upon testimony!
How do we know about Julius Caesar? Obviously, nobody alive presently ever saw him. The “witness” who first told you about Caesar is a “mediate” witness, as this person only first learnt of Caesar from another.
Your teacher relied on history textbooks and other teachers. Writers during Caesar’s time wrote about him. There is corroborating evidence. For example, there are busts, statues, and coins in his image.
Appealing to Authority
An argument from authority has it that “so-and-so argues X; ergo, you should believe in X.” Thomas Aquinas famously claimed that it’s the weakest form of argumentation. It’s not automatically fallacious, depending upon the authority who is appealed to and how he is appealed to. The authority needs to be a legitimate authority.
Expertise must be had by that identifiable person (or group). If you appeal to Albert Einstein’s opinion on a question about general relativity, that’s a good person to turn to. He’s not a good authority on, say, theology. Einstein was a physicist, not a theologian.
This expertise must be relevant and reliable. Einstein would be a reliable source on most questions about general relativity, though not insofar as the question’s answer is disputed by contemporary physicists. There are limits to how much we can appeal to Einstein in the context of contemporary physics. Certain issues would require a physicist alive today.
Warning! This suggests another limit. If experts disagree with each other, it would be a bad argument to just appeal to one of them. Political theorists, e.g., notoriously disagree with each other. We cannot settle a debate by appealing to one person’s authority.
Such arguments from (human) authority are probable only. It’s thus fallacious to cite an expert authority as a means to bring absolute certainty or a “knockdown” argument.
Finally, reliability is related to objectivity and disinterestedness. A used car salesman might not be objective nor disinterested when selling you a car. He’s probably not a good source to rely entirely on! So, we have to critically think about our sources.
Unsound Authority & Argumentum ad Verecundiam
Critically thinking about our sources will lead us to better reasoning.
Consider this example… I’m buying a used car.
Can I trust my used car salesman?
An argument to the effect that “this used car salesman said X about cars; ergo, it is probably true” is not a very trustworthy argument! We have the argumentum ad verecundiam fallacy, that is, an appeal to (unqualified) authority.
So, I go searching for an authority.
For example, I find a weekend talk radio host who talks about cars. I found out he is an authority. He’s an identifiable person. He has expertise by fixing cars and keeping up-to-date on different types of cars. The man has a good track record in fixing cars at his business. Additionally, we have no reason to think he is not objective and disinterested when giving car advice on the radio.
He seems to “pass” the test for a good authority!
However, we can ask further questions (to him or any authority):
– When he argues X, is this consistent with other experts in his field?
– When he argues X, does he or can he backup his argument?
These two questions are important.
We must be critical when citing authorities!
The argumentum ad verecundiam fallacy cites a witness who lacks sufficient credibility.
And someone might be more-or-less credible, but (for example) be cited dogmatically.
Example A: “I heard somewhere that a doctor said coffee is good for you.”
This doesn’t give us an identifiable source; hence, it’s not very strong.
Example B: “Paul Krugman claims tax increases won’t hurt the economy.”
Krugman is an economist. But experts disagree; hence, his claim shouldn’t be used in an argument to justify tax increases.
Example C: “Dawkins says that Aquinas’ arguments are easy to disprove.”
Richard Dawkins is an evolutionary biologist, not a philosopher; hence, he is not an expert to argue from.
Example D: “Aquinas said X about angels; so, it is guaranteed to be true.”
Aquinas is an expert theologian; however, this argument is too dogmatic. An argument from (human) authority will not give us absolute certainty.
Example E: “Most crooks agree that American police are unjust.”
Assuming that this is a statistically true statement, there is little reason to think that crooks are reliable.
Also, an argument from authority might be utterly unnecessary.
A mathematician, for example, would not be happy with a “proof” from authority! A layman might be content with it. The Abel–Ruffini Theorem tells us there is nothing analogous to the quadratic formula for anything higher than a fourth degree polynomial. Proving that is for a math major, studying abstract algebra. It would be sufficient, for most people, just to cite that theorem and feel satisfied (despite not having knowledge oneself of the proof).
On the other hand, why give an argument from authority for the Pythagorean Theorem? “The mathematician Serge Lang said that the Pythagorean Theorem is true; ergo, we should believe in it.” That’s fair enough. He’s an expert authority, writer of many important textbooks. It would be a much better argument, though, to actually give a proof!
Argumentum ad Populum?
Can “common opinion” be a legitimate authority?
Sometimes, yes!
Consider this example… If a lot of people claim that restaurant XYZ is good, then restaurant XYZ is likely good.
Let’s say your tastes roughly match the average person’s tastes. A lot of people claim that this new restaurant XYZ is good. So, you’ll likely agree.
What’s fallacious about that? Nothing!
Not all arguments appealing to common opinion are fallacious.
We have to be careful, not careless, in logic.
Philosopher Michael Huemer writes in Knowledge, Realty, and Value, “I think the fallacy lists lure people into thinking that some perfectly good inferences are wrong, because these perfectly good inferences sound like what the fallacy definitions are talking about. I refer to this as the ‘fallacy’ fallacy” (p. 49).
What exactly is the argumentum ad populum fallacy?
Huemer defines it as “Inferring that something is true from the fact that it is popularly believed” (ibid, p. 47). Clearly, if the majority of people believe in X, it doesn’t follow that X is guaranteed to be true. That’s, perhaps, trivially obvious. Huemer points out, though, that if most believe in X, there often is good reason to think X might be true (p. 49).
Similarly, Douglas Walton in Informal Logic: A Pragmatic Approach tells us that “ad populum arguments are not inherently wrong, but they are weak kinds of argumentation which can easily go wrong in various ways” (p. 113).
Imagine you’re in a new city. You want to know how to get somewhere. Several people give you the same directions. Is it reasonable to believe that following those directions will get you to your designation? Absolutely!
But where do things go wrong?
The fallacy of subjectivism has it that someone argues that X is the case because he believes or wants to believe X is the case. “I know it is true because I feel it is true” is an example of this fallacy.
Inasmuch as an ad populum argument merely references the subjective states of a number of people, it is engaging in the fallacy of subjectivism.
For example, there may be a number of people who believe in slavery. Does an increase in that number justify that belief? Does a decrease in number justify the contradictory of that belief?
No! Slavery is objectively wrong regardless of number.
By the way, how can somebody hold a false belief?
Basically, their belief doesn’t correspond to actual reality.
(Or it doesn’t correspond to what’s normatively or ethically the case.)
Truth is relational between one’s mind and the world. I have a true proposition X when there is a conformity between X and what it references. That’s what makes it objective, not subjective. You know, for example, “the Moon orbits the Earth.” It’s a true proposition because it conforms to what is in fact the case.
Often, in logic textbooks, it’s emphasized that the argumentum ad populum plays on the emotions of an audience. Patrick Hurley writes in my copy of his textbook that “The objective is to arouse a kind of mob mentality” (p. 115).
So it’s a bad argument that appeals to the prejudices of people. It tries to get people to engage in “groupthink.” Rather than arguing for the conclusion with objective evidence, e.g., it appeals to a group’s vanity or snobbery.
William Jevons writes something comparable in his very old logic book from 1888: “The argumentum ad populum … consists in addressing arguments to a body of people calculated to excite their feelings and prevent them from forming a dispassionate judgment upon the matter in hand” (p. 179).
Promoting a “group identity” is an example. An arguer tries to manipulate one’s need for acceptance or security to get us to buy into a conclusion.
Many advertisers (and politicians!) use these tactics.
“Everyone uses this product; so, you should, too.”
“All the smart people do it; so, you should too.”
“This is a value of democracy; so, believe it.”
[N.B.: proofreading of this page was provided by a friend. Thank you, Keith!]