Mastering Logical Fallacies
Significantly Improve the Way You Reason and Make Decisions
Thanks in part to the sponsorship of
The Book, "Logically Fallacious," by Bo Bennett, PhD,
this course is made available to you at a substantial discount. Sponsors have a subtle mention under the course title and links in the course resources — there are no intrusive image-based ads or audio ads in the course.
Quick Course Facts
102
Self-paced, Online, Lessons
102
Videos and/or Narrated Presentations
6.1
Approximate Hours of Course Media
About the Mastering Logical Fallacies Course
This is a crash course, meant to catapult you into a world where you start to see things how they really are, not how you think they are. The focus of this course is on logical fallacies, which loosely defined, are simply errors in reasoning.
Significantly Improve the Way You Reason and Make Decisions
- Learn how to recognize bad arguments
- Be able to articulate why an argument is bad
- Learn important details on over 100 of the most common logical fallacies
Learn the Fine Points of Common Fallacies
Fallacies have been around since the ancient Greek philosophers, and perhaps since the dawn of communication. Since the advent of social media, they seem to be around a lot more. Through mastering logical fallacies, you can not only correct others when they display a lapse in reasoning, but you can prevent yourself from making similar reasoning faux pas. You will be doing your part in making the world a more reasonable place.
Unlike other mentions of logical fallacies, the instructor goes into depth discussing many of the cognitive aspects of why we commit these fallacies and why we fall for them, offering academic insight in the world of logical fallacies.
While this course is written for the layperson, some concepts which may be new to you but play an important role in reasoning are introduced, in section1 we will cover the basics of reasoning, arguments, beliefs, fallacies, rationality, and being a smart-ass. In sections 2–18 we will go over in detail the most common logical fallacies, the variations of those fallacies, psychological reasons behind them, examples, and exceptions.
By the end of this course, you should be more confident in your ability to engage in rational arguments as well as present your own arguments.
Course Lessons
Full lesson breakdown
Lessons are organized by topic area and each includes descriptive copy for search visibility and student clarity.
Introduction to Logical Fallacies
7 lessons
While this course is written for the layperson, I do need to introduce some concepts which may be new to you but play an important role in reasoning, as well as issue a few warnings and explain how th…
Reason and rationality are not the same, and it is important to know the differences.
An "argument" is often seen as a negative experience, but this is not the type of argument we are talking about in this course.
Not all beliefs are formed the same, and not all people are biologically influenced by information in the same way.
There are formal and informal fallacies. The informal fallacies are arguments in themselves where there is a degree of subjectivity.
Sometimes calling out fallacies is the best course of action. Sometimes it's not. Know the difference.
Sometimes an argument is fallacious. Sometimes it is the person who is making the argument who is fallacious. And sometimes it is the person interpreting the argument who is fallacious.
Ad Hominem
6 lessons
In this section we will cover the Ad Hominem fallacy in detail, including five common forms: Ad Hominem (Abusive), Ad Hominem (Circumstantial), Ad Hominem (Guilt by Association), Ad Hominem (Tu quoque…
Suggesting that the person who is making the argument is biased, or predisposed to take a particular stance, and therefore, the argument is necessarily invalid.
When the source is viewed negatively because of its association with another person or group who is already viewed negatively.
Claiming the argument is flawed by pointing out that the one making the argument is not acting consistently with the claims of the argument.
To commit a preemptive ad hominem attack against an opponent. That is, to prime the audience with adverse information about the opponent from the start, in an attempt to make your claim more acceptabl…
Appeal to Common Belief
3 lessons
In this section we will cover the Appeal to Common Belief fallacy in detail, also known as: appeal to accepted belief, groupthink, appeal to widespread belief, appeal to the masses, appeal to belief, …
When the claim that most or many people in general or of a particular group accept a belief as true is presented as evidence for the claim. Accepting another person’s belief, or many people’s beliefs,…
A large group's aggregated answers to questions involving quantity estimation, general world knowledge, and spatial reasoning has generally been found to be as good as, and often better than, the answ…
Fallacies and Religion
5 lessons
In this section, we cover four fallacies that are directly related to religion: Appeal to Faith, Appeal to Heaven, Magical Thinking, and Spiritual Fallacy. It will be made clear that it is not faith, …
This is an abandonment of reason in an argument and a call to faith, usually when reason clearly leads to disproving the conclusion of an argument. It is the assertion that one must have (the right ki…
Asserting the conclusion must be accepted because it is the “will of God” or “the will of the gods”. In the mind of those committing the fallacy, and those allowing to pass as a valid reason, the will…
Making causal connections or correlations between two events not based on logic or evidence, but primarily based on superstition. Magical thinking often causes one to experience irrational fear of per…
Insisting that something meant to be literal is actually “spiritual” in as an explanation or justification for something that otherwise would not fit in an explanation.
Deception Through Confusion
3 lessons
In this section we will cover the Ambiguity Fallacy, Equivocation, and the Use-Mention Error in detail. These fallacies involve playing with language and not being clear. By the end of this section yo…
English is complicated and people can take advantage of that fact to confuse others.
A few examples of equivocation are presented that can be seen used today.
Fallacies of Authority
6 lessons
Using an authority as evidence in your argument when the authority is not really an authority on the facts relevant to the argument. As the audience, allowing an irrelevant authority to add credibilit…
Accepting a claim of a celebrity based on his or her celebrity status, not on the strength of the argument.
Asserting that a proposition is true solely on the authority making the claim while extreme cases also ignore any counter evidence no matter how strong. The authority could be parents, a coach, a boss…
Refusing to respond to give reasons or evidence for a claim by stating yourself as the ultimate authority in the matter. This is usually indicated by the phrases, “just trust me”, “because I said so”,…
Fallacies of Emotion
6 lessons
In this section, we cover five fallacies that are directly related to emotion: Appeal to Ridicule, Appeal to Pity, Appeal to Fear, Appeal to Emotion, Appeal to Desperation, and Appeal to Anger. We are…
This is the general category of many fallacies that use emotion in place of reason in order to attempt to win the argument. It is a type of manipulation used in place of valid logic.
Arguing that your conclusion, solution, or proposition is right based on the fact that something must be done, and your solution is "something."
When fear, not based on evidence or reason, is being used as the primary motivator to get others to accept an idea, proposition, or conclusion.
When the emotions of anger, hatred, or rage are substituted for evidence in an argument.
The attempt to distract from the truth of the conclusion by the use of pity.
Argument From Ignorance
5 lessons
In this section we will cover the Argument From Ignorance fallacy in detail, also known as: appeal to ignorance, absence of evidence, argument from personal astonishment, argument from Incredulity. By…
The assumption of a conclusion or fact based primarily on lack of evidence to the contrary. Usually best described by, “absence of evidence is not evidence of absence.”
There is an infinity of things we cannot prove -- the moon being filled with spare ribs is one of them. Now you might expect that any “reasonable” person would know that the moon can’t be filled with …
Plausibility is essentially believably, and people believe things for all sorts of reasons, many of which are not rational.
Not all people are equal in terms of dispositions to fallacies, and this one is no exception.
Circular Reasoning and the Fallacious Question
4 lessons
In this section, we cover three fallacies that are related: Begging the Question, Circular Reasoning, and Complex Question Fallacy. Circularity is common, sometimes humorous, and some would argue it i…
A type of reasoning in which the proposition is supported by the premises, which is supported by the proposition, creating a circle in reasoning where no useful information is being shared. This falla…
Any form of argument where the conclusion is assumed in one of the premises. Many people use the phrase “begging the question” incorrectly when they use it to mean, “prompts one to ask the question”. …
A question that has a presupposition built in, which implies something but protects the one asking the question from accusations of false claims. It is a form of misleading discourse, and it is a fall…
Fallacies of Poor Statistical Thinking
8 lessons
In inductive arguments, there is always a chance that the conclusion might be false, despite the truth of the premises. This is often referred to as “confidence level”. In any given study or poll, the…
Numbers don't lie, but them people who use them do.
Assuming flawless statistical models apply to situations where they actually don’t. This can result in the over-confidence in probability theory or simply not knowing exactly where it applies as oppos…
Drawing a conclusion based on a small sample size, rather than looking at statistics that are much more in line with the typical or average situation.
Using implausibly precise statistics to give the appearance of truth and certainty, or using negligible difference in data to draw incorrect inferences.
Drawing a conclusion about a population based on a sample that is biased, or chosen in order to make it appear the population on average is different than it actually is.
Ignoring statistical information in favor of using irrelevant information, that one incorrectly believes to be relevant, to make a judgment. This usually stems from the irrational belief that statisti…
Black and White Thinking
5 lessons
In this section, we cover the fallacy known as Black and White Thinking, or by its other common name, the False Dilemma. We discuss when and when this is not a fallacy, and cover many of the reasons w…
When only two choices are presented yet more exist, or a spectrum of possible choices exists between two extremes. False dilemmas are usually characterized by “either this or that” language, but can a…
Sometimes limiting to just two choices in not a fallacy.
This style of thinking is often associated with personality disorders, but most of us can do something about it.
The Impossible and the Possible
6 lessons
In this section, we cover fallacies associated with creating impossible standards. These include Moving the Goalposts, Nirvana Fallacy, Unfalsifiability, Proving Non-Existence, Definist Fallacy, Appea…
Demanding from an opponent that he or she address more and more points after the initial counter-argument has been satisfied refusing to conceded or accept the opponent’s argument.
Comparing a realistic solution with an idealized one, and dismissing or even discounting the realistic solution as a result of comparing to a “perfect world” or impossible standard. Ignoring the fact …
Confidently asserting that a theory or hypothesis is true or false even though the theory or hypothesis cannot possibly be contradicted by an observation or the outcome of any physical experiment, usu…
Demanding that one proves the non-existence of something in place for providing adequate evidence for the existence of that something. Although it may be possible to prove non-existence in special sit…
When a conclusion is assumed not because it is probably true, but because it is possible that it is true, no matter how improbable.
The Red Herring
4 lessons
Attempting to redirect the argument to another issue that to which the person doing the redirecting can better respond. While it is similar to the avoiding the issue fallacy, the red herring is a deli…
There are things we can do to discourage others from using red herrings on us.
The Legitimacy and Fallaciousness of the Slippery Slope
6 lessons
In this section, we focus on the Slippery Slope argument or fallacy, also known as: absurd extrapolation, thin edge of the wedge, camel's nose, and domino fallacy. When a relatively insignificant firs…
When a relatively insignificant first event is suggested to lead to a more significant event, which in turn leads to a more significant event, and so on, until some ultimate, significant event is reac…
Science that attempts to establish causality is basically a legitimate slippery slope.
Evidence is one of the factors that needs to be considered when deciding if a slippery slope is fallacious or not.
The number of events in the causal chain is one of the factors that needs to be considered when deciding if a slippery slope is fallacious or not.
The confidence level and probability of each event in the causal chain is one of the factors that needs to be considered when deciding if a slippery slope is fallacious or not.
Special Pleading
5 lessons
In this section we will look at Special Pleading. Special Pleading is applying standards, principles, and/or rules to other people or circumstances, while making oneself or certain circumstances exemp…
Applying standards, principles, and/or rules to other people or circumstances, while making oneself or certain circumstances exempt from the same critical criteria, without providing adequate justific…
Strong personal beliefs are more problematic than just emotions since they are more persistent and less malleable.
Compartmentalization is an unconscious psychological defense mechanism used to avoid cognitive dissonance, or the mental discomfort and anxiety caused by a person's having conflicting values, cognitio…
The Analogy - Both Friend and Foe
5 lessons
In this section we will look at fallacies related to the analogy, including Weak Analogy, Non Sequitur, Extended Analogy, and Reductio ad Hitlerum. Analogies can be an incredibly useful tool in rhetor…
When an analogy is used to prove or disprove an argument, but the analogy is too dissimilar to be effective, that is, it is unlike the argument more than it is like the argument.
When the conclusion does not follow from the premises. In more informal reasoning, it can be when what is presented as evidence or reason is irrelevant or adds very little to support to the conclusion…
Suggesting that because two things are alike in some way and one of those things is like something else, then both things must be like that "something else".
The attempt to make an argument analogous with Hitler or the Nazi party. Hitler is probably the most universally despised figure in history, so any connection to Hitler, or his beliefs, can (erroneous…
A Look at Nature
7 lessons
In this section we explore fallacies related to the concepts of nature and the natural, including Naturalistic Fallacy, Moralistic Fallacy, and Appeal to Nature. The Naturalistic Fallacy and Appeal to…
When used as a fallacy, the belief or suggestion that “natural” is always better than “unnatural”. Many people adopt this as a default belief.
The world "natural" is puzzling and quite arbitrary. Once we understand the problems with the natural/unnatural dichotomy, we will better understand the appeal to nature fallacy.
We have a tendency just focus on our own health concerns and ignore all the other important factors when evaluating the unnatural.
We cannot know for certain that something will be 100% safe in the future. This does not make it a serious risk.
When the conclusion expresses what ought to be, based only on actually what is more natural. This is very common, and most people never see the problem with these kinds of assertions due to accepted s…
The assumption that what ought to be is what is -- that the undesirable opposes nature.
Fallacies Worthy of Mention
10 lessons
In this final section, we briefly cover many different fallacies that are worthy of mention based on the frequency of their usage, and clear up some common confusion with these fallacies. We will cove…
Using historical preferences of the people (tradition), either in general or as specific as the historical preferences of a single individual, as evidence that the historical preference is correct. Tr…
Using social norms to determine what is good or bad. It is the idea that normality is the standard of goodness. This is fallacious because social norms are not the same as norms found in nature or nor…
A mode of argumentation or a form of argument in which a proposition is disproven by following its implications logically to an absurd conclusion. Arguments which use universals such as, “always”, “ne…
Fallacy of Division: Inferring that something is true of one or more of the parts from the fact that it is true of the whole. Fallacy of Composition: Inferring that something is true of the whole fro…
When only select evidence is presented in order to persuade the audience to accept a position, and evidence that would go against the position is withheld. The stronger the withheld evidence, the more…
Reasoning that further investment is warranted on the fact that the resources already invested will be lost otherwise, not taking into consideration the overall losses involved in the further investme…
An argument or position is self-sealing if and only if no evidence can be brought against it no matter what.
The process of force-fitting some current affair into one's personal, political, or religious agenda. Many people aren't aware of how easy it is to make something look like confirmation of a claim aft…
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