1. Critical Thinking and Making Decisions
Errors
Facts
Arguments

2. Sound Arguments Are the facts TRUE? Are the facts relevant
Are there sufficient facts

3. If not true, relevant or sufficient
The argument has a logical fallacy

4. Categories of Logical Fallacies
Ambiguity
Circular arguments
Presumption
Gambler’s
False cause
Relevance
Appeals to emotion
Bandwagon
Straw Man

5. Fallacies of Ambiguity
Accent Fallacy - fallacies that depend on where the stress is placed in a word or sentence
Equivocation - is committed when a term is used in two or more different senses within a single argument.
Fallacies of Ambiguity
The accent (or emphasis) used within the statement in question gives a different meaning from that of the words alone. The key principle is that emphasis put on a word or phrase directs attention to those words, signifying importance.
Emphasis in speech may be accidental or due to dialect, but often reflects the deeper meaning of what the person really intends.
Example
I wonder if you really want to do this. (Accent implies 'you want to do this')
What do you think people need about Charmix? (Accent says 'you need Charmix')
Discussion
The emphasis put on words in a sentence changes the meaning, often radically, which is one reason why the spoken word can communicate so much more than the written word (although limited emphasis may be used here).
Emphasis draws attention to words, indicating priority, although this often happens at a subconscious level (which is one reason it is often used in subtle sales and advertising pitches).
Because of the subconscious element, it is possible to understand what a person really means, and what they are actually feeling, from the emphasis they use.
We also interpret the emphasis subconsciously, which is an opportunity for the persuader to turn simple words into a powerful way of subtle communication.Explanation
Equivocation
This happens where the same word is used, but has two or more different meanings, leading to easy confusion as at least one of the meanings is likely to be false.
The weather forecast is for high winds. We're ok as we are in a valley.
The honey is set on the table.
He is a cut above the rest. This happens where the same word is used, but has two or more different meanings, leading to easy confusion as at least one of the meanings is likely to be false.

6. Fallacy of Circular Arguments
The truth of A is assumed within the original premise about A. Hence A is not really proven by the argument.
This may occur through a simple statement or via a more complex set of statements that go around in a circle and eventually 'prove' the original statement to be true.
Another variant is: If A is not wrong, then it is right.
Example
God exists because the Bible says so. The Bible was written by God.
I am not a liar.
This restaurant serves the best food in the town, because it has the best chef. It has attracted the best chef because it has the best reputation. It has the best reputation because the chef cooks the best food.
You are not bad, therefore you must be good.
Discussion
Begging the Question does not really answer it outside of its own assumptions. This happens when people accidentally or deliberately start from an unproven position and try to use this to prove the position. Like a house built on sand, the argument does not stand up to a light push. Someone asks `Why is Sammy so afraid of heights?' You explain `Because he has acrophobia'. Your argument is circular. `Acrophobia' means fear of heights. So the premise presupposes the conclusion is true. A really good argument would explain why Sammy has acrophobia.

7. Fallacies of Presumption
Either A or B is true. If A is true, B is therefore false. C is not an option.
The other person is offered a choice where rejecting one item acts as a selection of the other.
Example
Either you are with me or against me.
We have to spend less on hospitals, otherwise we won't be able to afford education improvements.
Discussion
This is based on the assumption that the choices offered are the only choices. By focusing on the choice, the decision to be made, the other person is distracted from the fact that there may be other alternatives.
False dilemmas
Complex questions

8. Gambler’s Fallacy
Chance is affected by more than random events. It can be controlled by luck, skill and specific identified events. When you hit a 'lucky' patch, you just cannot lose. When the odds are stacked against you, you have no chance.
Chance is affected by more than random events. It can be controlled by luck, skill and specific identified events. When you hit a 'lucky' patch, you just cannot lose. When the odds are stacked against you, you have no chance.
Example
I've lost three nights in a row. I will win big tonight. I'm wearing my lucky watch, just to make sure.
You know, every time it rains, I've come out without an umbrella and am miles from the car.
Discussion
One of our basic needs is for a sense of control, which we gain by seeking to predict the future and by attributing cause to events that occur. We also seek to win and avoid failure, which further drives us both to explain our losses outside ourselves and also to compensate for losses by trying to end up as a winner.
Habitual gamblers fall headlong into these traps. Many others are affected by it too. For example, 'Murphy's Law' (that when something goes wrong it will be the worst thing at the worst time) is often used to explain and provide comfort when things go wrong. Particularly for the gambler, it also means explaining winnings through external events and lucky charms (most of us prefer to explain winning through personal skills, although where chance is involved, we also fall into the trap). 'Luck' itself is an example, as it does not exist. What is random is random. The laws of statistics are all there are.
When things do go wrong and when our predictions fail, we need to be comforted in some way and the Gambler's Fallacy can be turned to this purpose also. We can explain failures as bad luck rather than incompetence or poor decision-making. We can take comfort in the fact that lady luck has gone out for the evening and there was nothing we could have done to change things. Examples:

9. Fallacy of False Cause
A causes B (without real proof that this causal relationship actually exists).
This causal relationship is often claimed when there is correlation between A and B (that they vary together) or a relatively distant causal connection.
Example
It is dark now, which makes it very dangerous. [It is not the dark that causes danger].
Drinking fresh water will keep you well. [It may contribute, but it is not the only or sufficient cause].
Money makes people arrogant. [Not all people, and not always just money]
Discussion
Cause-and-effect reasoning is a valid form of rational logic, but only if the causal relationship is established. It is very easy to find that two things vary together and assume cause-and-effect, but this only proves correlation. It may be, for example, that both are effects of a prior common cause.
Causal arguments are often wishful thinking, where the speaker is seeking to prove their case, and hopes (as with other fallacies) that their causal assertion is not challenged.False Cause is an informal logical fallacy (also known by the Latin non causa pro causa, "not a cause [taken] for a cause") where a participant invalidly assumes a causal relationship between two observations where it is not supported.
Example: "A black cat crossed my path at noon. An hour later, my mother had a heart-attack. Because the first event occurred earlier, it must have caused the bad luck later." This is how superstitions begin.
The most common examples are arguments that viewing a particular movie or show, or listening to a particular type of music “caused” the listener to perform an antisocial act--to snort coke, shoot classmates, or take up a life of crime. These may be potential suspects for the cause, but the mere fact that an individual did these acts and subsequently behaved in a certain way does not yet conclusively rule out other causes. Perhaps the listener had an abusive home-life or school-life, suffered from a chemical imbalance leading to depression and paranoia, or made a bad choice in his companions. Other potential causes must be examined before asserting that only one event or circumstance alone earlier in time caused a event or behavior later

10. Fallacies of Relevance
Attack the person in some way. For example:
Attack their expertise, questioning their qualifications or experience
Criticize their physical appearance or dress
Comment on their inability to make a good argument
Point out their junior status
Attack their values as being contrary to social norms
Interpret a minor error as major
Attach them to discredited others
Personal Attacks
Appeals to consequences
Description
Attack the person in some way. For example:
Attack their expertise, questioning their qualifications or experience
Criticize their physical appearance or dress
Comment on their inability to make a good argument
Point out their junior status
Attack their values as being contrary to social norms
Interpret a minor error as major
Attach them to discredited others
Example
You are not qualified to make such a statement.
You would say that, wouldn't you.
And who do you think is going to believe you.
Of course you will defend your own department.
You mean you have not considered Wikkin's work? That is a serious omission.
Discussion
Attacking the Person is a form of distraction, forcing them into defense and away from their argument. Most people, when personally attacked, respond with a fight-or-flight reaction and so either jump to their own defense or cognitively flee (and in doing so, drop any argument they are making).
Attacking people in public frames you as an aggressive person who attacks those who oppose you. Other people there will consequently be less likely to attack you or use strong arguments against you, for fear of being attacked by you, hence strengthening your power position.Fallacies of Relevance
Examples
Many of the familiar informal fallacies are fallacies of relevance, for example:
Personal attacks (arguments ad hominem) attempt to discredit a point of view by discrediting the person that holds it. The character of the person that holds a view, though, entails nothing about the truth of that view. Such arguments therefore commit a fallacy of relevance.
Appeals to consequences attempt to persuade someone to accept a position based either on the good consequences of their accepting it or on the bad consequences of their not accepting it. There is no guarantee, though, that the position that has the best consequences is true. Again, then, such arguments commit a fallacy of relevance.

11. Fallacy of Appeals to Emotion
Patriotic - asserts that a certain stance is true or correct because it is somehow patriotic, and that those who disagree are unpatriotic
Needs/Desire – tells the audience what it wants to hear to 'get them on side.'
Love – someone tries to induce acceptance of a claim by challenging love of a person or family
Anger - someone tries to induce acceptance of a claim by arousing indignation or anger
"Draping oneself in the flag." This argument asserts that a certain stance is true or correct because it is somehow patriotic, and that those who disagree are unpatriotic.
The best way to spot it is to look for emotionally charged terms like Americanism, rugged individualism, motherhood, patriotism, godless communism, etc. A true American would never use this approach. And a truly free man will exercise his American right to drink beer, since beer belongs in this great country of ours.
Appeal to needs/desires - speaker appeals to the basic needs, (food, work, security, health) growth needs (esteem, creativity etc.) and desires of the audience (love and approval, neighborhood, nation). He or she tells the audience what it wants to hear to 'get them on side.'
Appeals to the love of a person for his / her family. 'If you really love your children you will ….'
Appeals to your anger. She implies that 'you can't let this happen.'

12. Bandwagon Fallacy
The bandwagon fallacy is committed by arguments that appeal to the growing popularity of an idea as a reason for accepting it as true
“Everybody is doing it.”
If something is believed to be true by a lot of people then it must be true.
A variant is where the probability of truth is assessed by the number of people making the assertion (especially when you can see who is voting for and who is voting against the idea).
Example
Oh come on, everyone is saying that this is the right thing to do.
Your family all like the car...
In a survey, 8 out of 10 doctors agreed that this drug is dangerous.
Discussion
When we are uncertain about something, we turn to other people and assume they know what they are doing. We do the same with beliefs. The more other people believe something, the more likely we will be to accept that it is true (especially if we tend towards black and white thinking).

13. Straw Man Arguments
This fallacy includes any lame attempt to "prove" an argument by overstating, exaggerating, or over-simplifying the arguments of the opposing side. Such an approach is building a straw man argument. A straw man argument is one that misrepresents a position in order to make it appear weaker than it actually is, refutes this misrepresentation of the position, and then concludes that the real position has been refuted
Description
You have a several arguments for your case. I disprove one of those arguments, therefore the whole case is false.
Rather than attack the strongest argument, go for a weak one that is easier to attack.
Seek to change their real position to that where you can attack it.
Example
Astrology may be unproven, but neither has it been proved to be false.
You said the common man is important, so show me this 'common man'.
You want to spend less on education. Do you really want to cripple this country's future?
Discussion
By picking on a weak part of the argument and making a big deal of it, attention is distracted from the stronger reasons that should be the main part of the discussion.
The basic assumption is that if one small part of an argument can be proved false then, by association, the whole argument is also false.
A weak argument is one made of straw that is easily knocked over. Hence the name 'strawman'.