Fallacies are defined as mistakes in belief based on an unsound argument. There are many different types of such mistakes that can occur.
Fallacies in Arguments
Here are some examples of fallacies you may encounter when making an argument:
Appeal to Ignorance - An appeal to ignorance occurs when one person uses another person’s lack of knowledge on a particular subject as evidence that their own argument is correct.
For example: “You can’t prove that there aren’t Martians living in caves under the surface of Mars, so it is reasonable for me to believe there are.”
Appeal to Authority - This type of fallacy is also referred to as Argumentum ad Verecundia (argument from modesty). In this case, rather than focusing on the merits of an argument, the arguer will try to attach their argument to a person of authority in an attempt to give credence to their argument.
For example: “Well, Isaac Newton believed in Alchemy, do you think you know more than Isaac Newton?”
Appeal to Popular Opinion - This type of appeal is when someone claims that an idea or belief is true simply because it is what most people believe.
For example: “Lots of people bought this album, so it must be good.”
Association Fallacy- Sometimes called "guilt by association," this occurs when someone links a specific idea or practice with something or someone negative in order to infer guilt on another person.
For example: “Hitler was a vegetarian, therefore, I don’t trust vegetarians.”
Attacking the Person - Also known as Argumentum ad Hominem (argument against the man), this is quite a common occurrence in debates and refers to a person who substitutes a rebuttal with a personal insult.
For example: “Don’t listen to Eddie’s arguments on education, he’s an idiot.”
Begging the Question- This type of fallacy is when the conclusion of an argument is assumed in the phrasing of the question itself.
For example: “If aliens didn’t steal my newspaper, who did?” (assume that the newspaper was actually stolen).
Circular Argument- Also referred to as Circulus in Probando, this fallacy is when an argument takes its proof from a factor within the argument itself, rather than from an external one.
For example: “I believe that Frosted Flakes are great because it says so on the Frosted Flakes packaging.”
Correlation Implies Causation Fallacy - Otherwise known as Cum Hoc Ergo Propter Hoc, this is a fallacy in which the person making the argument connects two events which happen sequentially and assumes that one caused the other.
For example: “I saw a magpie and ten minutes later, I crashed my car, therefore, magpies are bad luck.”
False Dilemma/Dichotomy - Sometimes referred to as Bifurcation, this type of fallacy occurs when someone presents their argument in such a way that there are only two possible options.
For example: “If you don’t vote for this candidate, you must be a Communist.”
Non Sequitur - A fallacy wherein someone asserts a conclusion that does not follow from the propositions.
For example: “All Dubliners are from Ireland. Ronan is not a Dubliner, therefore, he is not Irish.”
Slippery Slope - Assuming that a very small action will inevitably lead to extreme and often ludicrous outcomes.
For example: “If we allow gay people to get married, what’s next? Allowing people to marry their dogs?”
As you can see, there are many different types of fallacies that you may encounter. Arguing with someone who uses false logic like this can be a frustrating experience, but now that you know these are examples of fallacies, you can identify what they are doing and spot the lapse in logic right away.