Probably the most commonly employed method of debate and discussion we tend to encounter – be it at blogs like this, in person, or at other online forums – is the use of logical fallacies to make arguments. Logical fallacies are, by definition, fundamentally irrelevant counterpoints to any argument because they are not based on reason or substantive merit, and consequently often assume false premises, fail to address the topic-at-hand, confuse correlation with causation, or other such shortcomings of critical thinking.
Unfortunately, the tendency to fall into a fallacy trap appears to be simple human nature. It is certainly a widespread phenomenon, especially when discussing issues that tend toward strong emotions and/or high-value stakes. I claim no natural resistance to this shortcoming, myself. I make this mistake daily, and must constantly be mindful of the potential for fallacy in order to avoid or subsequently correct it. I have reassessed and developed new positions on numerous issues because I have recognized, or someone has pointed out, that based a previous stance at least partially on fallacy. I have been forced to reevaluate supporting arguments for a given position so as to eliminate fallacious logic. This exercise necessarily continues and is very important to critical thinking generally.
So what are some common logical fallacies? There exists no exhaustively exclusive list of fallacies, of course, as they are products of constantly evolving, highly complex human nature. But, there are a number of well-documented and understood fallacies that seem to be most common among debaters in their various contexts. The following explore some of them that I have selected, in no particular order, based on my own personal encounters with them.
The ad hominem: Literally meaning “to the man,” the argument ad hominem typically manifests as a personal attack against the arguer, rather than a substantive attack against the argument itself. This manifests in numerous sub-fallacies of specific types, depending on context and structure, but fundamentally flows the same hypothetical way: “Joe Biden says gun control is necessary to reduce crime; Joe Biden is an idiot; therefore, gun control is not necessary to reduce crime.” This line of reasoning is fallacious simply because it presents no relevance to the merits of the argument itself. Gun control may or may not be necessary to reduce crime but the assertion (even if arguably factual) that Joe Biden is an idiot does not change the ultimate outcome of whether or not his argument presents substantive merit. Evenly correctly identifying hypocrisy, a very common ad hominem known as the tu quoque (“you too”), does not, unto itself, prove or disprove the substance of the given position that the hypocrite presents. In short, “play the argument, not the man.”
The straw man: Another commonly employed fallacy, the straw man seeks to address and subsequently rebuke a position that the arguer did not make and/or does not hold. It is essentially an argument of distraction, intended to address a more easily disproved position but one that is nonetheless irrelevant to the topic-at-hand. Typically, the straw man is either a result of its employer not fully understanding the original argument, or is employed to convince a third party who is ignorant of the original argument. In either instance, the straw man relies entirely on irrelevance for the wielder, and does nothing to substantively counterpoint a given position’s merits. A common straw man encountered when arguing for a limited, minarchist government is to be accused of endorsing, and then pointing out the problems with doing so, anarchy – which are of course are two meaningfully different positions.
The red herring: This fallacy develops when one participant in an argument introduces a digressive topic, intentionally or otherwise, to distract from discussing the actual topic-at-hand. Similar to a straw man, this fallacy is further enhanced because the invoker of the digression typically introduces a new topic that is easier for him/her to address. This can often be seen when politicians deflect direct questions in favor of other, perhaps more abstract responses or subject matter (e.g., the infamous Clintonian reply “what difference at this point does it make?”).
Circular reasoning/logic: Circular logic starts with a premise that is essentially the conclusion that the arguer seeks to prove. This usually takes a simplistic approach, by subtly restating the starting and end states as if they are different, when in fact they are fundamentally the same. For example, one argument supporting the theory of evolution is based on the premise that
…the fossil evidence that life has evolved from simple to complex forms over the geological ages depends on the geological ages of the specific rocks in which these fossils are found. The rocks, however, are assigned geologic ages based on the fossil assemblages which they contain. The fossils, in turn, are arranged on the basis of their assumed evolutionary relationships. Thus the main evidence for evolution is based on the assumption of evolution.
Similarly, one argument that superficially supports God and creation is that the Bible explicitly says God created the world, and if one believes in God then one must necessarily believe that what is conveyed in the Bible is true. Therefore, belief in God’s existence is affirmed by the Bible, which is true because it is the Word of God.
The appeal to authority: This fallacy suggests that the deliverer of a given argument lends some weight of expertise or otherwise correctness based solely upon his/her job, qualifications, or experience (i.e., his/her perceived authority). In a sense, this fallacy is another ad hominem, but works opposite outcomes. I see this fallacy employed quite a bit when asserting the conclusion of man-caused global warming (or is climate change nowadays?). Just because a scientist(s) claims this to be the case, does not necessarily make it so. Only the substantive merits of the science itself – which is to say the objective evidence, if fully understand and regardless of who presents it – can prove or disprove this theory. If this were not the case, then there would be a serious conflict of scientific logic when other scientists with comparably equal qualifications present different opinions/theories/findings. How does one reconcile this contradiction under the appeal to authority? This approach is also seen quite a bit when discussing controversial law enforcement, medical, gender-centric, and other issues. The fact that someone wears a particular uniform (or possesses certain “plumbing”) does not lend any substantive weight to their argument; only the substance of the argument itself does this. As with other fallacies, there are subordinate forms of this fallacy.
The appeal to tradition: This fallacy is commonly employed by political conservatives who assert that traditional ideas, policies, and/or positions are true/superior because they have been around so long. This is not self-evidentiary logic, but rather an irrelevant appeal that often leads to missed opportunities, incorrect conclusions, and inefficiency among other negative outcomes. I also see this commonly on a micro level where I work, where the organization will pursue flawed, inefficient, and often illogical policies simply because “we’ve always done it that way.”
The appeal to novelty: This fallacy, the opposite of the appeal to tradition, is more commonly employed by political liberals who assert that new ideas, policies, and positions are true/superior simply because they are new and/or presumed innovative. This also is not a self-evidentiary use of logic, and presents an irrelevant supposition that can lead to poor conclusions and outcomes.
The bandwagon fallacy: Another common fallacy somewhat related to the appeal to novelty is known as the bandwagon fallacy. Democracy itself, at least insofar as it is commonly corrupted in American politics, is a demonstration of this fallacy on a very large scale. Logically, just because a simple majority of people (or in the case of electoral politics, a minority plurality) all at least superficially agree with a given premise does not necessarily make it factually accurate. Again, to use a modern example, substantive science is not correctly deemed accurate or inaccurate based on consensus – only the merits of the objective evidence can prove or disprove a given theory. I can make a sound argument that virtually all modern scientific “discoveries” (assuming they are indeed correct) disprove previously held consensus beliefs among scientists. A very similar, related fallacy is the appeal to popularity, which supposes a given position is true simply because it is widely held or endorsed (e.g., Keynesian economics).
The fallacy of division: This fallacy asserts that a characteristic, property, or truism of a collective whole in any context must necessarily mean the constituent parts of that whole embody these same properties individually. This fallacy lay at the heart of identity politics, for example, whereby people assume all individuals of a given demographic must subscribe to a particular political point of view simply because the collective demographic measurably trends that way. To a lesser extent, this fallacy further harms critical thinking because it tends to associate causation with the collective outcome, rather than accounting for the numerous variables that lead individuals to exhibit such collective properties (i.e., are black Americans typically Democrats because they are black, or do other substantive factors exist that contribute to this demographic trending Democratically?).
The fallacy of composition: This fallacy asserts that a characteristic, property, or truism of an individual constituent part (or even all of the parts) of the whole must necessarily mean the entire collective embodies these same properties. This fallacy probably manifests most often in the form of demographic prejudice, whereby racism or sexism is rationalized on the grounds of individual encounters or even actual evidence. For example, the fallacy of composition illogically suggests that because some violent criminals are black, all (or even most) black people must be violent criminals; or, because some self-identified Christians have murdered people associated with pro-abortion policies, all (or even most) Christians must be willing to kill in similar fashion. A similar fallacy to this is known as the hasty generalization fallacy.
The appeal to force: The appeal to force fallacy wielder essentially seeks to coerce an audience to a given position or conclusion with the threat or actual use of violence. “Disbelief, such arguments go, will be met with sanctions, perhaps physical abuse; therefore, you’d better believe.” This argument is making a disturbing rise in certain argumentative circles, most notably in the ongoing global warming policy debate (the fallacious patterns involved with this topic should be easily graspable). I posit that when one resorts to such an approach, they have already conceded that their position lacks the substantive merit to sufficiently demonstrate truth.
The weak analogy: All analogies are comparisons, meant to make a point easier to digest and understand by introducing a more common or easily understood scenario for the audience to grasp. The key to avoiding the weak (or false) analogy fallacy, however, is to ensure a proverbial “apples-to-apples” comparison. Often, this is not what occurs. Perhaps the most common use of this fallacy today is when arguers invoke careless references to Nazi Germany to add a stark exclamation to one’s point (see the colloquial Godwin’s Law), and in many cases dare someone to refute the argument on the basis of being somehow associated with or accepting of Nazi policies and behaviors. Analogies are helpful in debate to be sure, but only if they avoid this fallacious application.
Proof by assertion: This fallacy is commonly seen in politics, where the demagogue continues to assert a given conclusion, regardless of its merit correctness, in order to exhaust opponents of the argument. The determined demagogue will continue this fallacious rhetoric until the assertion is generally accepted as true by the intended audience. Obviously, simply repeating a given position does not, unto itself, prove the correctness of the position in question. Unfortunately, however, this is a very effective exploitative tactic, exemplified, for instance, when politicians assert that the debate surrounding man-made global warming is “settled,” despite the existence of substantive contradictory evidence that has heretofore gone properly unaddressed.
Appeal to the stone: The appeal to the stone fallacy occurs when an arguer dismisses a position as being absurd, without providing any evidence to, let alone proving outright, the given position’s supposed absurdity. If someone were to dismiss climate change predictions, for example, without refuting the merits of these claims with actual evidence and sound reasoning, that person would be invoking a logical fallacy regardless of the whether their refutation happens to be true or untrue.
Complex question fallacy: This fallacy occurs when leading questions are asked that presume a conclusion imbedded within the question beforehand, despite whether or not this presumption is true. This fallacy, purposeful or not, consequently leaves the person fielding the question in a position to which they cannot logically respond without affirming a possibly untrue premise. It follows thus: “Are you going to admit that you’re wrong?” The question asserts the position that the questioned individual is wrong, without first demonstrating so. If the person in question is not actually wrong, they have now found themselves in a logic trap: if s/he says “no,” it is an indirect affirmation of their being wrong but being unwilling to acknowledge so; however, answering “yes” provides direct affirmation of the premise. This fallacy is very commonly committed by the media.
Cum hoc fallacy: The cum hoc, meaning “with this,” is a fallacy that suggests because two things occur together, and are thusly correlated, there correspondingly must exist a causative relationship as well. But this illogical approach incorrectly ignores other relevant factors and likely more accurate explanations of causation. For example, if motorcycle crashes are the leading cause of death among American service members, a death rate that is reflected higher in the military than in the civilian populace for the affected age group (20-24 years), the cum hoc would suggest that the military is the correlation and the cause because they are correlated (the fallacious but nonetheless romanticized “adrenaline junkie” explanation is often offered as explanation for this correlation). But a relevant factor that goes overlooked by this fallacy, and could at least partially explain these incidents better, is that young people in this age group are far more financially sound in the military across the demographic than their civilian counterparts and thusly far more likely to own and operate motorcycles (and subsequently crash them) than their civilian counterparts in this group.
False dilemma fallacy: The false dilemma typically involves presenting two, and only two, extremes as available outcomes to choose from in a given scenario when more than two viable choices actually exist. In truth, so long as only a subset of possible choices is presented as viable when more are available, regardless of the actual number, this circumstance qualifies as a false dilemma. An excellent two-part breakdown of this fallacy is presented by YouTube thinker Lindybeige here and here.
The “No true Scotsman” fallacy: This fallacy manifests when the arguer seeks to reassert a previously offered universal statement, that has subsequent been proved false, by slightly amending the original universal statement on an ad hoc basis in such a subjective way that practically cannot be proved/disproved. The fallacy generically goes: “No Scotsman would do such a thing,” and then is amended to “Well, no true Scotsman would do such a thing” when a contradictory counterexample is offered in rebuttal to the original assertion. Perhaps the greatest persistent blunder of 20th and 21st century geopolitical foreign policy is, in fact, based entirely on the “No true Scotsman” fallacy: the Democratic peace theory (i.e., no true democracies war with each other, despite ever-increasing incidences of warfare on the part of and directly between world democracies during this period).
Argument to moderation: The argument to moderation suggests that when presented with two extreme or otherwise opposite/conflicting positions, the moderate (or middle-ground compromise, if you will) is inherently the best position or choice, without regard to the substantive merit(s) presented be each extreme – or some other unconsidered alternative option. This fallacy is very prevalent in modern American politics, wherein some voters, pundits, and politicians insist that the best course for the country is a so-called bipartisan compromise, usually without any regard or consideration for other relevant factors such as constitutional law, ethics, predictable negative outcomes, etc.
Other fallacies that, for some form of brevity’s sake have not made this list but are nonetheless equally illogical, can be found here. I highly recommend reviewing them for general awareness and avoidance, but also because it is simply an interesting examination of human psychology. Critical thinking is the key to solving real problems, and thinking, by definition, involves the rejection of fallacious logic.