Fallacy Definition Example Ad hominem Attacking the person instead of the argument. "You can't trust John's climate change opinion; he's not a scientist." Straw man Misrepresenting an opponent's argument to make it easier to attack. Opponent says "We need gun control," you reply "They want to ban all guns and leave us defenseless." Appeal to authority Claiming something is true because an authority says so, without evidence. "This diet works because a celebrity endorses it." False dilemma Presenting two options as the only possibilities when more exist. "You're either with us or against us in this war." Slippery slope Arguing a minor action will lead to extreme consequences without evidence. "If we allow same-sex marriage, soon people will marry animals." Hasty generalization Drawing a broad conclusion from a small sample. "I met two rude New Yorkers, so all New Yorkers are rude." Red herring Introducing irrelevant information to distract from the issue. Discussing taxes, but shifting to the opponent's personal life. Bandwagon Arguing something is true because many believe it. "Everyone is buying this stock, so it must be a good investment." Post hoc ergo propter hoc Assuming one event caused another because it followed it. "I wore lucky socks and won; the socks caused the win." Circular reasoning Using the conclusion as a premise. "God exists because the Bible says so, and the Bible is God's word." Equivocation Using a word with multiple meanings ambiguously. "A bank can hold money or river water, so it's the same." Appeal to emotion Manipulating emotions instead of using logic. "Think of the children!" to push a policy without data. No true Scotsman Redefining a group to exclude counterexamples. "No true patriot would criticize the government." Tu quoque Dismissing criticism by pointing out hypocrisy. "You say smoking is bad, but you smoke too." Burden of proof Shifting the need to prove a claim to the opponent. "Prove aliens don't exist." Genetic fallacy Judging something based on its origin, not merits. "That idea came from a bad person, so it's wrong." Middle ground Assuming the compromise between extremes is correct. "One says 2+2=4, another says 6; truth is 5." Composition Assuming the whole has properties of its parts. "Atoms are invisible, so the table is invisible." Division Assuming parts have properties of the whole. "The team is great, so every player is great." Begging the question Assuming the conclusion in the premise. "Oppressive laws are unjust because they're unfair." Bias Definition Example Confirmation bias Seeking or interpreting evidence to support existing beliefs. Ignoring studies that contradict your political views while citing those that agree. Anchoring bias Relying too heavily on the first piece of information encountered. Negotiating salary: starting offer of $50k anchors you, even if worth $70k. Availability heuristic Judging likelihood by how easily examples come to mind. Fearing plane crashes more than car accidents due to media coverage. Dunning-Kruger effect Unskilled people overestimating their ability; experts underestimating. Novice coder thinking they're expert after one tutorial. Hindsight bias Seeing past events as predictable after they occur. "I knew the stock market would crash" after it happens. Sunk cost fallacy Continuing a behavior due to prior investment. Watching a bad movie to the end because you paid for the ticket. Bandwagon effect Adopting beliefs because many others do. Buying a product because it's trending on social media. Loss aversion Preferring to avoid losses over equivalent gains. Holding losing stocks longer than selling winners. Endowment effect Valuing owned items more than identical non-owned ones. Refusing to sell a mug for $5 but wouldn't buy it for $5. Status quo bias Preferring things to stay the same. Sticking with a bad phone plan to avoid change. Optimism bias Overestimating positive outcomes for oneself. "It won't rain on my wedding day" despite forecasts. Framing effect Decisions influenced by how information is presented. 90% fat-free sounds better than 10% fat. Actor-observer bias Attributing own actions to situations, others' to traits. "I was late due to traffic; he's late because he's lazy." Self-serving bias Taking credit for successes, blaming failures on externals. Good grade: "I'm smart"; bad grade: "Test was unfair." Halo effect One positive trait influencing overall perception. Attractive person assumed to be kind and smart. Negativity bias Giving more weight to negative experiences. Remembering one criticism over ten compliments. Recency bias Overemphasizing recent events. Judging a player by last game, not season average. Illusion of control Overestimating influence over uncontrollable events. Blowing on dice for luck in gambling. Fundamental attribution error Overemphasizing personality in others' behavior, ignoring situations. "She cut me off because she's rude," not considering her emergency. Survivorship bias Focusing on successes while ignoring failures. "Dropouts like Gates succeed, so college is useless" ignoring failed dropouts.