Claim vs. Evidence vs. Reason

• Claim - a statement that answers a question

• Evidence - The data and details that support a claim

• Reason - Ties together the claim and the evidence

Types of Reason

• Deductive reasoning - tests an existing theory

  • The conclusion must be true if the premises are true

  • Slow and hard - must be based on facts that are testable

  • Ex. All humans have brains (barring any medical anomalies). John is a human. Therefore, John has a brain.

• Inductive reasoning - develops a theory

  • The truth of the premise does not necessarily guarantee the truth of the conclusion

  • Quick and easy - used in daily life

  • Ex. All nerds use Reddit. John is a nerd. Therefore, John uses Reddit.

    • This is untestable, and therefore it's a stretch to say all nerds use Reddit. Is John a nerd? How does one test for that? Even if he is a nerd, he doesn't necessarily use Reddit

    • However, this type of inductive reasoning is commonly used and thought to be Deductive

• Abductive reasoning - makes a probable conclusion from what you know

  • Cause-and-effect relationship, while induction seeks to determine general rules.

  •  Ex. An abandoned bowl of hot soup might mean the owner of the soup left recently or is likely to return soon.

Logical Fallacies

• Ad hominem - The fallacy of attacking the person making an argument instead of addressing the argument itself.

• Ad populum - The fallacy of assuming that a statement is true because it is widely believed or accepted.

• Appeal to authority - The fallacy of assuming that a statement is true simply because it is made by an authority figure, without considering the evidence.

• Appeal to emotion - The fallacy of using emotions, such as fear or sympathy, to support an argument, rather than presenting evidence and reasoning.

• Appeal to ignorance - The fallacy of arguing that something must be true simply because it has not been proven false, or vice versa.

• Appeal to nature - The fallacy of assuming that something is good or right simply because it is "natural."

• Appeal to novelty - The fallacy of assuming that something is good or right simply because it is new or modern.

• Appeal to personal incredulity - The fallacy of assuming that something must be false simply because you can't imagine how it could be true.

• Appeal to tradition - The fallacy of assuming that a particular practice or idea is true or good simply because it has been used or believed for a long time.

• Bandwagon - The fallacy of assuming that an argument is true or valid simply because many people believe it or do it.

• Burden of proof - The fallacy of assuming that the burden of proof lies with the person who is skeptical of a claim, rather than with the person making the claim.

• Circular reasoning - The fallacy of using the conclusion of an argument as a premise, thereby assuming the truth of the very thing that needs to be proven (see Claim vs. Evidence).

• Composition/division - The fallacy of assuming that what is true of a part must also be true of the whole, or vice versa.

• Confirmation bias - The tendency to seek out and interpret information in a way that confirms our preexisting beliefs, while ignoring or dismissing information that contradicts our beliefs.

• Equivocation - The fallacy of using ambiguous language or changing the meaning of a word in the course of an argument to support a conclusion.

• Fallacy of accent - The fallacy of changing the meaning of a statement by emphasizing different words or phrases.

• Fallacy of anecdotal evidence - The fallacy of using personal anecdotes or stories as evidence to support a general conclusion.

• Fallacy of suppressed evidence - The fallacy of ignoring or suppressing evidence that contradicts an argument.

• Fallacy of the beard - The fallacy of assuming that because there is no clear boundary between two things, they must be the same thing. 

• Fallacy of the single cause - The fallacy of assuming that a complex event or phenomenon has a single cause, when in fact there may be multiple causes or factors involved.

• False attribution - The fallacy of attributing a statement or idea to someone who did not actually make it.

• False cause - The assumption that one event causes another even without sufficient evidence to support the relationship (see Inductive Reasoning).

• False compromise - The fallacy of assuming that the middle ground between two extreme positions must be the correct or reasonable position.

• False dilemma - The fallacy of presenting fewer options as if they are the only possibilities, when in fact there may be other options available. 

• False analogy/equivalence - The fallacy of assuming that two things are equal or similar in all respects, when in fact they are not.

• Gambler's fallacy - The fallacy of assuming that a future event is more likely to occur based on previous events, when in fact each event is independent of the others.   

• Genetic fallacy - The fallacy of dismissing an argument or idea because of its origin or source, rather than evaluating its merits.

• Hasty generalization - The fallacy of drawing a conclusion based on insufficient evidence, such as making a generalization about an entire group based on a small sample.

• Loaded question - The fallacy of phrasing a question in such a way that it assumes a particular answer or implies a particular conclusion.

• Moving goalposts - The fallacy of changing the criteria for success or achievement after the fact in order to make a position or argument appear stronger.

• Red herring - The fallacy of introducing a completely unrelated topic into an argument in order to divert attention from the original issue.

• Post hoc ergo propter hoc - The fallacy of assuming that because one event occurred before another event, it must have caused the second event. 

• Slippery slope - The fallacy of assuming that a small initial action will inevitably lead to a chain of events that result in an extreme or negative outcome.

• Straw man - The fallacy of misrepresenting someone's argument in order to make it easier to attack, rather than addressing the actual argument.

• Texas sharpshooter - The fallacy of cherry-picking data or evidence that supports a particular position, while ignoring evidence that contradicts it.